Corethrella Coquillett, 1902

Amaral, André P., Mariano, Rodolfo & Pinho, Luiz Carlos, 2023, Description of five new species of frog-biting midges (Diptera, Corethrellidae) from Brazil and examination of new morphological characters with utility for taxonomic and phylogenetic studies, European Journal of Taxonomy 874 (1), pp. 1-120 : 108-120

Key to New World Species of Corethrella Coquillett, 1902 (modified from Borkent 2008)

Males of the following species are unknown: C. amabilis Borkent, 2008 , C. anniae Borkent, 2008 , C. atricornis Borkent, 2008 , C. aurita Borkent, 2008 , C. cabocla Feijó, Belchior, Marialva & Pessoa, 2021 , C. colombiana Borkent, 2008 , C. flavitibia Lane, 1939 , C. fuscifimbria Amaral & Pinho sp. nov., C. fusciradialis Borkent, 2008 , C. globosa Borkent, 2008 , C. gloma Borkent, 2008 , C. grandipalpis Borkent, 2008 , C. hirta Borkent, 2008 , C. ielemdei Feijó, Ramires , Lima & Pessoa, 2021, C. inca Lane, 1939, C. jenningsi Lane, 1942 , C. kerrvillensis (Stone, 1965) , C. kipferi Dorff, Borkent & Curler, 2022 , C. menini Feijó, Picelli, Ríos-Velásquez & Pessoa, 2021 , C. orthicola Borkent, 2008 , C. patasho Amaral & Pinho sp. nov., C. pillosa Lane, 1939 , C. pindorama Amaral & Pinho sp. nov., C. procera Borkent, 2008 , C. redacta Borkent, 2008 , C. truncata Borkent, 2008 , C. unifasciata Amaral & Pinho sp. nov., C. unisetosa Borkent, 2008 , and C. yanomami Amaral, Mariano & Pinho, 2019 . The females of C. munteantaroku Amaral, Mariano & Pinho, 2019 , C. remiantennalis Borkent, 2008 and C. stenostyla Amaral, Bello-González & Pinho, 2021 are also unknown. Figures marked with an asterisk (*) refer to Borkent (2008).

1. Wing with discrete subapical band (*fig. 71a), with no dark scales of this band extending to wing apex (or, at most, with dark scales on R 4+5 reaching wing apex).......................................2

– Wing either completely plain or with banding but if with darkened scales beyond midlength band, these extend along veins R 3, R 4+5, and M 1 to the wing apex (*fig. 71f)...........................6

2. Hind tibia mostly pale, with dark pigmentation restricted to apex (*fig. 54a) .......................... .................................................................................................... C. vittata Lane, 1939 (in part)

– Hind tibia with dark pigmentation at base and apex (*fig. 54b)................................................3

3. Wing with basal band of pigmented scales and membrane (*fig. 70n).......................................4

– Wing without basal band (subbasal band present) (*fig. 71b)......................................................5

4. Halter yellow or very light brown (*fig. 54b); base of R 1 without patch of dark scales (so that R 1 has one group of dark scales on its apical portion) (*fig. 70n); length of male fore Ta3/Ta4 = 0.55–0.64; male gonocoxite long and slender (*fig. 95a); tarsomeres uniformly pigmented (*fig. 54b) ................................................................................................... C. edwardsi Lane, 1942

– Halter dark brown (*fig. 54c); R 1 of female wing with patch of dark scales at about ¼ of its length from base (so that R 1 has a patch of dark scales between the midlength and subbasal band); in a few specimens these dark scales appear continuous with those on R 1 of the midlength band (*fig. 71a); male with length of fore Ta3/Ta4 = 0.76–0.80; male gonocoxite shorter and tapering (*fig. 95b); tarsomeres 2–4 of at least hind leg banded (as in *fig. 55c) ..................................................... ..................................................................................... C. quadrivittata Shannon & Del Ponte, 1928

5. Clypeus with 1 seta (*fig. 18y); hind femur uniformly dark brown or dark brown and with apex even more darkly pigmented (*fig. 54d) ................................................. C. whartoni Vargas, 1952

– Clypeus with 18–28 setae (*fig. 18u); hind femur apically pale, with at most a small, discrete dark spot near its apex (*fig. 53d) .......................... C. belkini Borkent, 2008 (in part)

6. Wing either completely plain and without any differentiated markings of any sort or, if with some darkening or pattern, the scales along the entire anterior margin more or less uniformly pigmented (*fig. 67n) (some adults with slight differentiation but in these it is not very discrete (*figs 69i, 72i); male of C. munteantaroku with somewhat discrete band); male gonocoxite with basal 2–4 setae of the dorsal row of setae stout and expanded and bent subapically (*fig. 87c) or with the dorsal row of setae all slender (*fig. 82)...........................................................7

– Wing with distinct banding, so that the anterior margin of the wing has clearly differentiated patches of pale scales both basal and distal to the dark scales of at least the midlength band (*fig. 71f); male gonocoxite with dorsal row of setae all slender (*fig. 82)...........................................51

7. Hind tibia with distinct and discrete pigmentation, contrasting with paler remainder of tibia (*fig. 52a).....................................................................................................................................................8

– Hind tibia without discrete pigmentation, at most with non-discrete pigmentation at apex (*fig. 42a), or with poorly defined basal and apical pigmentation (*fig. 43b).........................................14

8. Midfemur with pale base, with darker midlength portion, and a darker apex (*fig. 42c); hind tibia with distinct pigmentation at base contrasting with pale remainder of tibia, with at most only slight pigmentation at apex; gonocoxite uniformly pale, with 2 basal dorsal setae expanded and bent sub-apically, with 3 dorsomedial stout setae on a common sclerotized plate (*fig. 86b) ..... ........................................................................................................................ C. alticola Lane, 1939

– Midfemur either uniformly pigmented (*fig. 51c) or with some darker pigmentation only at very apex (*fig. 51d); hind tibia with distinct pigmentation at both base and apex, contrasting with paler remainder of tibia (*fig. 51c); gonocoxite pale with very apex with darker pigmentation (*fig. 79c), with dorsal setae slender and more or less equal in size, with 1 dorsomedial seta (*fig. 93a) (males of C. fusciradialis and C. unisetosa unknown).....................9

9. Head and thorax yellowish; thorax differentially pigmented, with yellow areas and areas of darker pigmentation (*fig. 52a); male with abdominal sternites III–VII each pigmented only along posterior margin (*fig. 79d).................................................................................................10

– Head and thorax dark brown; thorax uniformly pigmented (*fig. 51b); male with abdominal sternites uniformly pigmented (*fig. 79c)......................................................................................12

10. Fore- and hind coxae and trochanters equally dark brown; katepisternum mostly light or medium brown (*fig. 51c) .......................................................................................... C. infuscata Lane, 1939

– Forecoxa and trochanter pale, contrasting with dark hind coxa and trochanter (*fig. 51d); katepisternum mostly pale, with limited ventral portion and dorsal margin with darker pigmentation (*fig. 51d)........................................................................................................................................11

11. Palpus dark brown (*fig. 11g); clypeus with 8–16 setae (*fig. 18n) ............ C. fulva Lane, 1939

– Palpus pale (*fig. 11f); clypeus with 1 seta (*fig. 18m) ................ C. unisetosa Borkent, 2008

12. Wing pale, with some dark scales restricted to posterior margin of wing near very base (*fig. 70b); tarsomeres 2–4 of at least mid- and hind leg banded (*fig. 51b); female with each of flagellomeres I–III elongate (*fig. 29l) ..................................... C. tarsata Lane, 1942

– Wing with dark scales over most of wing, with a small lighter patch centered over or just basal of r-m (*figs 69i, 72i); tarsomeres 2–4 of at least mid- and hind leg not banded (*fig. 49c); female with each of flagellomeres I–III short (*figs 29e, 32g).....................................13

13. Palpus segments I–III as dark as clypeus (*fig. 10f); female flagellomere III relatively short, less than 0.5 of flagellomere IV (*fig. 29e); flagellomeres XI–XII each with two sensilla coeloconica ....................................................................................... C. contraria Borkent, 2008 ♀♀

– Palpus segments I–III lighter than clypeus (*fig. 15a); female flagellomere III relatively long, more than 0.8 of flagellomere IV (*fig. 32g); flagellomeres XI–XII each with one sensillum coeloconicum (male unknown) ............................................................... C. fusciradialis Lane, 1942

14. Scutum light brown with lateral vitta distinctly dark brown; katepisternum uniformly medium brown (*fig. 42b) .............................................................. C. manaosensis (Lane & Cerqueira, 1958)

– Scutum either uniformly pigmented or with varied pigmentation (*fig. 42a) but lateral vitta not distinctively and contrastingly dark brown; if scutum light brown and lateral vittae medium brown, then ventral portion of katepisternum paler (*figs 40d, 43c).........................15

15. Midfemur with slightly (*fig. 43b) to significantly darker (*fig. 43a) pigmentation at very base...16

– Midfemur uniformly or nearly uniformly pigmented (*fig. 44c) or with very base slightly paler (*figs 40d, 42a) than remainder of femur........................................................................................20

16. Thorax dark brown (*fig. 42d), contrasting with pale or light brown halter ........................................ ....................................................................................................................... C. peruviana Lane, 1939

– Thorax yellow (some with pattern of pigmentation) (*fig. 43c) to dark brown (*fig. 43a), halter equal in pigmentation to that of scutellum...................................................................................17

17. Palpus segment III pale, contrasting with light brown palpus segment V (*fig. 7i) ....................... ................................................................................................................. C. inornata Borkent, 2008

– Palpus entirely brown (*fig. 7h).....................................................................................................18

18. Wing uniformly pigmented (*fig. 67l); thorax entirely dark brown or with, at most, slightly lighter and darker patches of pigmentation on scutum (*fig. 43a) ... C. ramentum Borkent, 2008

– Wing with faint band at midlength (*figs 67n, 68a); thorax yellow or light brown (*fig. 43c)....19

19. Female antennal flagellomeres I–III short (*fig. 27f); male wing length = 1.21–1.60 mm (not entirely separable from C. blanda ) ............................................................................... C. pallida Lane, 1942

– Female antennal flagellomeres I–III elongate(*fig. 27g);male wing length= 1.10–1.35mm (not entirely separable from C. pallida ) ................................................................................ C. blanda Dyar, 1928

20. Wing veins with midlength band present (although poorly differentiated along anterior margin) (*figs 70k, 72k).................................................................................................................................21

– Wing veins without pattern of darkened scales, at most with slightly darker scales on basal ⅓ to ½ of wing (*fig. 67h).....................................................................................................................23

21. Four long setae on frons, near ventral margin of eye bridge; anepimeron bare; male genitalia with 2 apically bent and expanded setae in the dorsal row (Amaral, Mariano & Pinho 2019: fig. 2e) ............... C. munteantaroku Amaral, Mariano & Pinho, 2019 (♀♀ unknown)

– Two large setae on frons; anepimeron with setae; male genitalia with simple setae in the dorsal row (*fig. 98d)..................................................................................................................................22

22. Female flagellomere I elongate (*fig. 32i); femora without scales; tarsomeres 2–4 of mid- and hind legs uniformly pigmented (*fig. 60a) .................................................. C. travassosi Lane, 1942

– Female flagellomere I short (*fig. 30i); femora with abundant scales; tarsomeres 2–4 of mid-and hind legs banded (*fig. 53c) .......................... C. melanica Lane & Aitken, 1956 ♀♀ (in part)

23. Male (males of C. anniae , C. globosa , C. grandipalpis , C. kerrvillensis , C. redacta , and C. truncata unknown)..........................................................................................................................................24

– Female (female of C. remiantennalis unknown)..............................................................................34

24. With elongate, thick, apically flattened seta on flagellomere VI or X (*fig. 20b–c)....................25

– Without modified seta on any flagellomere.................................................................................26

25. Flagellomere VI with elongate, thick, apically flattened seta (*fig. 20b) .......................................... ............................................................................................................ C. blandafemur Borkent, 2008

– Flagellomere X with elongate, thick, apically flattened seta (*fig. 20a) ............................................. ......................................................................................................... C. remiantennalis Borkent, 2008

26. Gonocoxite with one thick dorsomedial seta, arising directly from undifferentiated cuticle (*fig. 85c)..................................................................................................................................................27

– Gonocoxite with 2–3 thick dorsomedial setae arising from a sclerotized plate (*fig. 85d)............31

27. Head broad in anterior view; posterior anepisternum divided by a diagonal suture, forming a triangle at inferior portion; abdominal segments I–VII, IX uniformly medium brown, segment VIII pale, at least posteriorly.............................................................................................129

– Head rounded in anterior view (*fig. 6i); ventral portion of posterior anepisternum not differentiated from dorsal portion (*fig. 36b); abdomen uniformly pigmented........................28

28. Four long setae on frons, near ventral margin of eye bridge; flagellomeres I–II moderately elongate (Amaral, Mariano & Pinho 2019: fig. 4h); veins (other than costal and wing margin) only with setae, lacking scales (*fig. 73c); CuP reaching wing margin ............................................................. ...................................................................................... C. xokleng Amaral, Mariano & Pinho, 2019

– Two large setae on frons, near ventral margin of eye bridge; flagellomeres I–II short (*fig. 19i; Caldart et al. 2016: fig. 3c); veins with setae or scales; CuP reaching wing margin or not......29

29. R 2 longer than the stem of R 2+3 (from fork of R 2+3 and R 4+5 to fork of R 2 and R 3) (*fig. 67b) ...... .................................................................................................................. C. rotunda Borkent, 2008

2 2+3 2+3 4+5 2 3 – R shorter than the stem of R (from fork of R and R to fork of R and R) (*fig. 67f).......30

30. CuP reaching wing margin (Caldart et al. 2016: fig. 3g); halter as dark as scutellum ................... ................................................................................................... C. yucuman Caldart & Pinho, 2016

– CuP not reaching wing margin (*fig. 61k); halter slightly lighter than scutellum ........................... ................................................................................................................. C. brevivena Borkent, 2008

31. Dorsal row of setae on gonocoxite only with slender, simple setae (*fig. 85d) ................................. ............................................................................................................... C. carariensis Borkent, 2008

– Basal 2–3 setae of dorsal row of setae enlarged and bent subapically (*fig. 87d).........................32

32. Trochanter of foreleg pale or only slightly pigmented, contrasting with the brown base of the forefemur (as in *fig. 44c) .......................................................................... C. amazonica Lane, 1939

– Trochanter of foreleg brown and with the same degree of pigmentation as the base of the forefemur (as in *fig. 44d)..............................................................................................................33

33. Empodium with one bifid branch, Y-shaped ( Fig. 6E ) ......... C. bifida Amaral & Pinho sp. nov

– Empodium with two bifid branches ( Fig. 21C ) ............. C. davisi Shannon & Del Ponte, 1928

34. Flagellomere I globular (*fig. 26k) to squat (*fig. 27h)..................................................................35

– Flagellomere I moderately (*fig. 27i) to very elongate (*fig. 27j)..................................................37

35. Flagellomere IV much shorter than flagellomere V (*fig. 27h); wing veins with scales (as in *fig. 73d) ............................................................................................................ C. truncata Borkent, 2008

– Flagellomere IV not much shorter than flagellomere V (*fig. 26k–l); wing veins only with slender setae (*fig. 73c).................................................................................................................................36

36. R 2 longer than the stem of R 2+3 (from fork of R 2+3 and R 4+5 to fork of R 2 and R 3) (*fig. 67g) ....... ................................................................................................................... C. globosa Borkent, 2008

– R 2 short, shorter than the stem of R 2+3 (from fork of R 2+3 and R 4+5 to fork of R 2 and R 3) (*fig. 67f) ..................................................................................................... C. brevivena Borkent, 2008

37. Ventral portion of katepisternum completely pale or very light brown, contrasting with medium brown dorsal portion (*fig. 40a)....................................................................................................38

– Ventral portion of katepisternum medium to dark brown (*fig. 40c), with at most dorsal margin pale (*fig. 42a)..................................................................................................................................40

38. Wing with slender scales on all veins (as in *fig. 73b); empodia slender .................................... .................................................................................................................... C. anniae Borkent, 2008

– Wing with setae instead of scales on non-marginal veins (as in *fig. 73c); empodia thick (Amaral, Mariano & Pinho 2019: fig. 4e).....................................................................................39

39. Coronal suture absent (*fig. 16c); two large setae on frons near ventral margin of eye bridge; scutellum pale ..................................................................................... C. kerrvillensis (Stone, 1965)

– Coronal suture present, short (Amaral, Mariano & Pinho 2019: fig. 5a); four large setae on frons near ventral margin of eye bridge; scutellum pigmented ..................................................... ..................................................................................... C. xokleng Amaral, Mariano & Pinho, 2019

40. Head nearly globular in anterior view (*fig. 7a); posterior anepisternum dorsoventrally elongate, posterior portion pale or with only very light pigmentation (*figs 36b, 40b).............41

– Head broader than long in anterior view (*fig. 7e); ventral portion of posterior anepisternum triangular, darkly pigmented (*figs 36c, 44d)................................................................................46

41. Coronal suture short or absent, at most extending only to margin of area between ommatidia (as in *fig. 16e).........................................................................................................................42

– Coronal suture more elongate, extending to area between ommatidia (as in *fig. 16d).........44

42. Vein R 2 shorter than the stem of R 2+3 (Caldart et al. 2016: fig. 2g) ................................................ ................................................................................................... C. yucuman Caldart & Pinho, 2016

– Vein R 2 longer than the stem of R 2+3 (*fig. 67c, e).....................................................................43

43. Wing length = 1.28–1.45 mm; wing scales slender but apically expanded (as in *fig. 73b); flagellomeres X–XII each with 2 sensilla coeloconica ............ C. grandipalpis Borkent, 2008

– Wing length = 0.98–1.07 mm; wing veins only with slender setae (as in *fig. 73c); flagellomeres X–XII each with 1 sensillum coeloconicum ......... C. blandafemur Borkent, 2008

44. Coronal suture incomplete, extending ventrally about midway along area between ommatidia (as in *fig. 16f); halter darkly pigmented (*fig. 40b) ........................... C. rotunda Borkent, 2008

– Coronal suture complete, extending to ventral margin of area between ommatidia ( Fig. 4A ); halter paler than scutellum ( Fig. 4G )...........................................................................................45

45. Mediotergite mostly pale with a dorsal dark spot ( Fig. 4G ); empodia thick ( Fig. 4K ) ................ ............................................................................................ C. pindorama Amaral & Pinho sp. nov

– Mediotergite uniformly medium brown (Dorff et al. 2022: fig. 4); empodia slender ................ .................................................................................... C. kipferi Dorff, Borkent & Curler, 2022

46. Flagellomere II short (*fig. 27i) ............................................................... C. redacta Borkent, 2008

– Flagellomere II elongate (*fig. 27k)..............................................................................................47

47. Two large setae on frons, near ventral margin of eye bridge; clypeus with 3–4 setae on dorsal surface; palpus pale/light brown (Amaral, Mariano & Pinho 2019: fig. 8a) ........................................ ...................................................................................... C. cambirela Amaral, Mariano & Pinho, 2019

– Four large setae on frons; clypeus with 8–41 setae on dorsal surface; palpus brown.................48

48. Femora without scales ........................................................................ C. carariensis Borkent, 2008

– At least midfemur with narrow scales (as in *fig. 74c)..............................................................49

49. Trochanter of foreleg pale or only slightly pigmented, contrasting with the brown base of the forefemur (*fig. 44c); with no anepimeral setae ....................................... C. amazonica Lane, 1939

– Trochanter of foreleg brown and with the same degree of pigmentation as the base of the forefemur (*fig. 44d); with 0–12 anepimeral setae........................................................................50

50. With sensilla coeloconica on each of flagellomeres I–III, V–XIII; empodium with two bifid branches ( Fig. 21C ) ................................................................... C. davisi Shannon & Del Ponte, 1928

– With sensilla coeloconica on flagellomeres I–II, VI–XIII; empodium Y-shaped, with one bifid branch ( Fig. 6E ) .............................................................................. C. bifida Amaral & Pinho sp. nov

51. Anepimeron pale with small, anterior, light brown spot; remainder of thorax nearly entirely pale or very light brown (*fig. 56b) .............................. C. longituba Belkin, Heinemann & Page, 1970

– Anepimeron more extensively pigmented; remainder of thorax from light to dark brown, some with variable pigmentation (*figs 48b, 49b, 50a)..........................................................................52

52. Basal half of hind tibia without any distinct pigmentation, equal in color to lightened apex of hind femur (*fig. 50c) or with base of hind tibia overall very slightly darker than apex of hind femur (without any discrete patch of pigmentation) (*figs 47c, 59d).............................................53

– Basal half of hind tibia with at least light pigmentation, contrasting with paler apex of hind femur (*figs 52c, 56a)...................................................................................................................62

53. Wing with discrete basal and subbasal bands (*fig. 70m) ......... C. vittata Lane, 1939 (in part)

– If wing with some darker scales in area basal to midlength band, then these in a single patch (*fig. 69b).........................................................................................................................................54

54. Basal portion of midfemur distinctly darker than base of hind femur (Almeida et al. 2021: fig. 6a) ......................................................................... C. ielemdei Feijó, Ramires , Lima & Pessoa, 2021

– Midfemur and base of hind femur equally pigmented (*fig. 47c)................................................55

55. Coronal suture elongate, reaching ventral margin of eye bridge; two long setae on frons, near ventral margin of area between ommatidia (Amaral, Mariano & Pinho 2019: fig. 9a); flagellomere I elongate; prescutal suture elongate, reaching dorsocentral row of setae; halter as dark as scutellum ............................................. C. yanomami Amaral, Mariano & Pinho, 2019

– Coronal suture absent, short or elongate; if elongate, then four long setae on frons; flagellomere I short or elongate; if elongate, then prescutal suture short, not extending more than half way to dorsocentral row of setae; halter pale or paler than scutellum....................56

56. Scutellum, most of scutum and of anepimeron pale; ventral portion of posterior anepisternum, katepisternum, and mediotergite medium brown ( Fig. 10G ) .................................................................. ............................................................................................... C. unifasciata Amaral & Pinho sp. nov

– Anepimeron medium to dark brown; scutum, scutellum, katerpisternum and mediotergite light to dark brown......................................................................................................................................57

57. Midfemur completely or nearly completely pigmented, with at most only very apex lighter (*fig. 47c); female flagellomeres I–II short (*fig. 28i)................................................................58

– Midfemur with at least apical 1/7 more lightly pigmented than basal portion (*fig. 50d); female flagellomeres I–II short (*fig. 28j) to elongate (*fig. 29i)........................................................59

58. Mid- and hind leg tarsomere 2–4 banded (*fig. 47c); abdominal segments I–VII light to medium brown, with sternites I–II more darkly pigmented than remaining sternites (*fig. 78e) ............... ...................................................................................................... C. bicolor Borkent, 2008 (in part)

– Tarsomeres uniformly pigmented (*fig. 59d); abdominal segments I–VII uniformly medium brown (male unknown) ................................................................................ C. gloma Borkent, 2008

59. Sternites I and II darkly pigmented, contrasting with remaining pale or very light brown sternites (*fig. 78f) ........................................................................................................ C. badia Borkent, 2008

– Sternites equally pigmented (*fig. 78l).........................................................................................60

60. Abdominal segments I–IX and cercus uniformly dark brown (Almeida et al. 2021: fig. 4c); foretibia mostly dark brown, with only basal 0.1 paler (Almeida et al. 2021: fig. 4a) .. ............................................................ C. cabocla Feijó, Belchior, Marialva & Pessoa, 2021

– Abdomen light to medium brown, with segments VIII and IX dark brown; cercus medium brown; foretibia mostly light brown, with at most apical half darker pigmented (*fig. 50c)....61

61. Female flagellomeres I–III elongate (*fig. 29i); male with a sensillum coeloconicum on flagellomere VIII; female flagellomeres IX–XIII each with only a single sensillum coeloconicum; male with gonocoxite long and slender (*fig. 91d), nearly uniformly light brown, with only very base somewhat darker (*fig. 78l) .................................................... C. lepida Borkent, 2008

– Female flagellomeres I–III short (*fig. 29j); male without a sensillum coeloconicum on flagellomere VIII; female flagellomeres IX–XII each with two sensilla coeloconica; male with gonocoxite short and wider (*fig. 92a), with at least basal third medium brown and lightening apically (*fig. 79a) ........................................................... C. caribbeana Borkent, 2008

62. Midfemur uniformly yellow, contrasting with somewhat darker brown base of hind femur (*fig. 48a)..................................................................................................................................................63

– Base of midfemur with light to dark brown pigmentation equal to that of base of hind femur (*figs 46c, 49c–d)...........................................................................................................................64

63. Katepisternum completely pigmented (*fig. 46d) (male unknown) ...... C. jenningsi Lane, 1942

– Katepisternum mostly pale, with dorsal or posterodorsal portion more darkly pigmented (*fig. 48a) .......................................................................................................... C. douglasi Borkent, 2008

64. Abdomen with medial portion of tergites II–IV and all of sternites II–IV pale, contrasting with medium to dark brown segments V–X (male unknown) ............ C. flavitibia Lane, 1939

– Abdomen uniformly pigmented medium to dark brown or, at most, with sternites I–II and segment IX darker brown than remainder of abdomen (*fig. 78d)............................................65

65. Midfemur with scales (in some, with only narrow scales) (*fig. 74c–d)....................................66

– Midfemur without scales ( C. brandiae and C. hispaniolensis with thick setae)........................73

66. Basal ⅔ of wing primarily with dark scales (*fig. 70k) .................................................................... ................................................................................. C. melanica Lane & Aitken, 1956 ♀♀ (in part)

– Area basal to midlength band on wing with, at most, a band of dark scales restricted to C, R, M and M 4 (*fig. 70g)...........................................................................................................................67

67. Palpus short, dark brown (*fig. 9a); gonocoxite uniformly dark brown (*fig. 78a) (some undescribed species with pale palpi but with uniformly dark brown gonocoxites discussed under C. appendiculata in Borkent 2008) ................................................... C. fuscipalpis Borkent, 2008

– Palpus elongate, pale or light brown (*fig. 11h); gonocoxite either completely pale (*fig. 79g) or with a dark base and lighter apex (*fig. 79h) (male of C. hirta unknown)............................68

68. Femora with narrow scales at least at apex (*fig. 74c); gonostylus with long (*fig. 93b) or short apical setae (*fig. 93c)....................................................................................................69

– Femora with broad scales (*fig. 74d); gonostylus with only short apical setae (*fig. 93d)...71

69. Wing with broad band of dark scales basal to midlength band (*fig. 70g) ... C. hirta Borkent, 2008

– Wing with, at most, some dark scales basal to the midlength band restricted to C, Sc and a few on M (*fig. 70f)...............................................................................................................................70

70. Hind femur more extensively pigmented (male with basal 0.61–0.68 dark, female with basal 0.58–0.67 dark) (*fig. 52b); gonocoxite with dark base, lightening apically (*fig. 79f); gonostylus with long apical setae (*fig. 93b) ................................................... C. squamifemora Borkent, 2008

– Hind femur with less pigmentation(male and female with basal 0.42–0.55dark)(*fig. 52d);gonocoxite light brown to nearly completely pale, with base contrasting with darker tergite IX and rest of abdomen (*fig. 79g); gonostylus only with short apical setae (*fig. 93c) ... C. albicoxa Borkent, 2008

71. Female ............................................................................................ C. appendiculata Grabham, 1906

– Male..................................................................................................................................................72

72. Mediobasal seta positioned more distally, with dorsomedial seta from base/ gonocoxite length = 0.24–0.29 ........................................................................................ C. melanica Lane & Aitken, 1956

– Mediobasal seta positioned more basally, with dorsomedial seta from base/ gonocoxite length = 0.17–0.25 ........................................................................................ C. appendiculata Grabham, 1906

73. Male (males of C. amabilis , C. atricornis , C. aurita , C. colombiana , C. inca, C. orthicola , C. pillosa and C. procera are unknown)..........................................................................................................74

– Female..............................................................................................................................................97

74. Gonocoxite pale or very light brown, strongly contrasting with medium to dark brown segment IX (*fig. 78e)...................................................................................................................................75

– Segment IX and at least base of gonocoxite more or less equally pigmented (*fig. 78i).......79

75. Scutum yellow, contrasting with darker pleura (as in *fig. 47a) ...... C. briannae Borkent, 2008

– All of thorax dark brown (as in *fig. 47b).................................................................................76

76. Abdominal segments I–VIII uniformly brown, with at most sternites I–II slightly darker (*fig. 78b)..................................................................................................................................................77

– Abdominal segments I–VIII lightly pigmented, with at least sternites I–II and VI–VII more darkly pigmented brown (*fig. 78d)..............................................................................................78

77. Foreleg Ta3/Ta4 = 0.91–1.00; segments VIII and IX uniformly brown (*fig. 81a); dark pigmentation on hind tibia not discrete (as in *fig. 57b); subbasal seta short, aedeagus tapering gradually to apex (*fig. 98a) ...................................................................................... C. blantoni Borkent, 2008

– Foreleg Ta3/Ta4 = 0.53–0.67; segment IX darker than segment VIII (*fig. 78b); dark pigmentation on hind tibia discrete (as in *fig. 46b); subbasal seta elongate, aedeagus tapering near apex (*fig. 89c) .................................................................................................... C. ananacola Dyar, 1926

78. Palpus dark brown, contrasting with pale antenna (as in *fig. 9g); hind tibia with basal patch of pigmentation small, faint (as in *fig. 47c) ....................... C. bicolor Borkent, 2008 (in part)

– Palpus and antenna equally pale (as in *fig. 9f); hind tibia with basal patch of pigmentation well-developed, conspicuous (as in *fig. 47b) ..................................... C. brandiae Borkent, 2008

79. Abdominal segment VIII lightly pigmented, contrasting with dark segment IX (*figs 78i, 80l) ..........................................................................................................................................................80

– Segments VIII and IX equally medium to dark brown (*fig. 80e, j).........................................85

80. No more than apical 0.4 of hind femur pale (as in *fig. 57a); hind tibia with basal and apical darker pigmentation not discrete (as in *fig. 57a)........................................................................81

– At least apical 0.5 of hind femur pale (as in *fig. 49b–d); hind tibia with basal and apical darker pigmentation discrete and well-defined (as in *fig. 49b)...............................................82

81. Halter more lightly pigmented than scutellum (as in *fig. 57a) ... C. selvicola Lane, 1939 (in part)

– Halter and scutellum equally dark (as in *fig. 57c) ............... C. incompta Borkent, 2008 (in part)

82. Aedeagus very narrow, rounded apically (*fig. 91a)....................................................................83

– Aedeagus tapered, pointed apically (*fig. 90d)..............................................................................84

83. Wing with dark pigmentation restricted to narrow midlength band and M just basal to r-m (*fig. 63f; more clearly seen in female, *fig. 69h); palpus pale (as in *fig. 10e); halter pale, lighter than scutellum (as in *fig. 49b) .......................................................... C. lopesi Lane, 1942

– Wing with more extensive pigmentation, with broad midlength band and more extensive pigmentation more basally (*fig. 63g; more clearly seen in female, *fig. 69i); palpus dark brown (as in *fig. 10f); halter dark, similar to scutellum (as in *fig. 49c) ....... C. contraria Borkent, 2008

84. Mid and hind leg tarsomeres 2–4 banded (as in *fig. 49d); gonocoxite medium to light brown basally, paler apically (*fig. 78k); flagellomere III without sensilla coeloconica ............................... ........................................................................................................ C. guadeloupensis Borkent, 2008

– Tarsomeres uniformly brown (as in *fig. 48d); gonocoxite uniformly dark brown (*fig. 78h); flagellomere III with a sensillum coeloconicum ........................................... C. cardosoi Lane, 1939

85. Halter and scutellum equally dark brown (as in *fig. 55a).........................................................86

– Halter pale or light brown, paler than dark brown scutellum (as in *fig. 56a)..........................88

86. Flagellomeres X–XII each with two sensilla coeloconica ...... C. incompta Borkent, 2008 (in part)

– Flagellomeres X–XII each with one sensillum coeloconicum......................................................87

87. Flagellomeres IV–X each with numerous sensilla trichodea distal to those of the basal whorl (*fig. 65k) ......................................................................................... C. ranapungens Borkent, 2008

– Flagellomeres IV–X each with few sensilla trichodea distal to those of the basal whorl (*fig. 65l) ............................................................................................................. C. curta Borkent, 2008

88. Hind tarsomeres 2–4 banded (as in *fig. 55c)...........................................................................89

– Hind tarsomeres 2–4 uniformly brown (as in *fig. 55d)..........................................................90

89. Wing with dark scales of subapical band not extending to wing apex (*fig. 64f and as in *fig. 70l) ................................................................................................. C. belkini Borkent, 2008 (in part)

– Wing with dark scales of subapical band extending to wing apex (*fig. 64m) ............................ .................................................................................................. C. hispaniolensis Borkent, 2008

90. Clypeus elongate (as in *fig. 18a–c).............................................................................................91

– Clypeus broad or nearly square (as in *fig. 18a–f)......................................................................92

91. Wing veins with narrow scales (as in *fig. 73b); pigmentation of head, thorax (as in *fig. 56a but figure somewhat darker than in reality) and abdomen light brown ..... C. aridicola Borkent, 2008

– Wing veins with well-developed scales (as in *fig. 73e); pigmentation of head, thorax (*fig. 55d) and abdomen dark brown ........................................................... C. puella Shannon & Ponte, 1928

92. Flagellomeres X–XII each with two sensilla coeloconica............................................................93

– Flagellomeres X–XII each with one sensillum coeloconicum....................................................94

93. Palpus medium brown, with apex of segment III pale, segment IV somewhat lighter (*fig. 14c); antenna medium brown; coronal suture short, extending ventrally about midway along interocular space ................................................................................................ C. wirthi Stone, 1968

– Palpus pale (Amaral & Pinho 2015: fig. 9); antenna light brown; coronal suture elongate, reaching ventral margin of interocular space ............................ C. borkenti Amaral & Pinho, 2015

94. Gonocoxite uniformly dark brown (*fig. 80j); gonostylus with subbasal seta short (*fig. 97b) or elongate (*fig. 97c)..........................................................................................................................95

– Gonocoxite brown basally, pale apically (*fig. 80l); gonostylus with subbasal seta elongate (*fig. 97d)..................................................................................................................................................96

95. Gonocoxite dorsal setae 1–3 expanded subapically (*fig. 97b); gonostylus with apical half very slender, with the subbasal seta very short ............................................ C. brakeleyi (Coquillett, 1902)

– Gonocoxite dorsal setae 1–3 tapering subapically (*fig. 97c); gonostylus with apical half of a similar diameter as near the subbasal seta, with the subbasal seta elongate ........ C. condita Borkent, 2008

96. Flagellomere III with a sensillum coeloconicum .............................. C. selvicola Lane, 1939 (in part)

– Flagellomere III without a sensillum coeloconicum ............................ C. dicosimoae Borkent, 2008

97. Flagellomeres II and III both very short (*fig. 31d).......................................................................98

– Either or both flagellomeres II and III more elongate (*fig. 31b)...............................................100

98. Halter and scutellum equally dark brown (*fig. 55b); hind tibia either uniformly pigmented or with slightly darker, poorly defined pigmentation at base and apex (*fig. 55b) ......................................... ......................................................................................................................... C. curta Borkent, 2008

– Halter more lightly pigmented than scutellum (*fig. 49a) or with both halter and scutellum light brown (*fig. 49b); hind tibia with discrete pigmentation at both base and apex (*fig. 49a)....99

99. Wing with patch of dark scales on M, just basal to r-m (*fig. 69h); flagellomeres X–XII each with two sensilla coeloconica; flagellomere VII without sensilla coeloconica ...... C. lopesi Lane, 1942

– Wing with dark scales basal to midlength band restricted to basal band (*fig. 69g); flagellomeres X–XII each with one sensillum coeloconicum; flagellomere VII with sensilla coeloconica ............ ................................................................................................................... C. amabilis Borkent, 2008

100. Flagellomeres I and II very short, with flagellomere I nearly globular (*fig. 28i) ..................... ................................................................................................... C. bicolor Borkent, 2008 (in part) – Flagellomeres I and II more elongate, with flagellomere I elongate (*fig. 29f)....................101

101. Thorax medium to dark brown, with halter and scutellum equally dark or halter only slightly lighter than scutellum (*fig. 55a)..........................................................................102

– Thorax light (*fig. 56a) to dark brown (*fig. 57d), either uniformly pigmented or with some patterns of pigmentation (*fig. 47a); halter distinctly paler than scutellum (*fig. 60b) or if equal in pigmentation, both light brown..................................................................................109

102. Wing midlength band with dark scales only on the costa, R 1, R 2+3, M (missing in some) and M 4 (none present on R 4+5, CuA) (*fig. 71e); abdominal sternite uniformly brown or with sternites I–II darker than at least sternites III–IV (as in *fig. 78d)...........................103 – Wing midlength band with dark scales on all veins (*fig. 71c); sternites uniformly pigmented...................................................................................................................................................105

103. Four large setae on frons between ventromedial area of ommatida ( Fig. 8B ); wing without subapical dark band ( Fig. 8J ); coronal suture elongate, almost reaching ventral margin of interocular space ( Fig. 8A ) .................................................... C. patasho Amaral & Pinho sp. nov. – Two large setae on frons (*fig. 16e); wing with or without subapical dark band; if present, then coronal suture short, not extending ventrally at interocular space.................................104

104. Wing with patch of dark scales on R and M, about halfway between base of wing and midlength band and a subapical dark band (*fig. 71e); abdominal segments I–VII uniformly medium brown .................................................... C. hispaniolensis Borkent, 2008 – Wing without dark scales halfway between base of wing and midlength band and without subapical band (*fig. 68n); abdominal segments light brown with sternites I–II dark brown (as in *fig. 78d) ................................................................................ C. brandiae Borkent, 2008

105. Femora and tibiae slender (especially on hind leg) (*fig. 48c).............................................106 – Femora and tibiae thick (*fig. 55a).........................................................................................107

106. Hind tibia with basal and apical pigmentation not discrete (*fig. 60c); flagellomeres IX–XII each with two sensilla coeloconica ......................................................... C. procera Borkent, 2008 – Hind tibia with basal and apical pigmentation discrete (*fig. 48c); flagellomeres IX–XII each with one sensillum coeloconicum ............................................ C. orthicola Borkent, 2008 (in part)

107. Flagellomeres IX–XII each with two sensilla coeloconica ............ C. incompta Borkent, 2008 – Flagellomeres IX–XII each with a single sensillum coeloconicum.....................................108

108. Flagellomere XIII without apical bifurcation .................................................................................. ................................................................ C. menini Feijó, Picelli, Ríos-Velásquez & Pessoa, 2021 – Flagellomere XIII with apical bifurcation .................................... C. ranapungens Borkent, 2008

109. Clypeus elongate (*fig. 18a–c)...................................................................................................110 – Clypeus either wide or square (*fig. 18a–g)..............................................................................111

110. Pigmentation of head, thorax, and abdomen light brown (*fig. 56a); with 2–6 anepimeral setae; wing with midlength band with dark scales on R 4+5 (*fig. 71g); wing veins with narrow scales (as in *fig. 73b) ....................................................... C. aridicola Borkent, 2008 – Pigmentation of head, thorax, and abdomen dark brown (*fig. 55d); with 9–19 anepimeral setae; wing with midlength band without dark scales on R 4+5 (*fig. 71f); wing veins with well-developed scales (as in *fig. 73f) ................................. C. puella Shannon & Ponte, 1928

111. Wing with a well-developed subbasal band, extending from anterior to posterior margin of wing, and with scales along the hind margin distinctly pigmented (so that there are two sections of dark scales along the basal ⅔ of the hind margin) (best seen in alcohol specimens) (*fig. 71i) ...... C. brakeleyi (Coquillett, 1902) + C. condita Borkent, 2008 (♀♀ not distinguishable)

– Wing without pigmented scales basal to the midlength band or if these are present, they are either scattered or restricted to the base or anterior veins of the wing (so that the scales along the posterior margin of the wing basal to the midlength band are more or less unicolorous, except for some with somewhat darkened posterior scales at very base of wing) (*figs 71k, 72b)......112

112. Flagellomere III with a sensillum coeloconicum......................................................................113 – Flagellomere III without a sensillum coeloconicum................................................................121

113. Flagellomeres X–XII each with two sensilla coeloconica (these not known for C. inca from Peru, keyed below).....................................................................................................................114 – Flagellomeres X–XII each with one sensillum coeloconicum.............................................116

114. Coronal suture elongate (Amaral & Pinho 2015: fig. 3); flagellomere IV with one sensillum coeloconicum .............................................................................. C. borkenti Amaral & Pinho, 2015 – Coronal suture short (as in *fig. 16f); flagellomere IV without sensilla coeloconica.........115

115. At least mid and hind leg tarsomeres 2–4 with banding (*fig. 46b) ........................................... .................................................................................................. C. ananacola Dyar, 1926 (in part) – Mid and hind leg tarsomeres uniformly pigmented (*fig. 57d) ................. C. wirthi Stone, 1968

116. Hind tibia with basal and apical pigmentation not discrete, blending gradually into light brown midlength portion (*fig. 57a).....................................................................................................117 – Hind tibia with basal and apical pigmentation discrete, distinctly separated by pale area (*fig. 58b).............................................................................................................................................118

117. Wing with dark scales in basal band on C, Sc, R 1 and M (*fig. 71k) .... C. selvicola Lane, 1939 – Wing without any dark scales basal to midlength band other than along posterior margin (*fig. 71l) ....................................................................................................... C. blantoni Borkent, 2008

118. Palpus segment III short, relative to segment IV (*fig. 34m).............................................119 – Palpus segment III elongate, relative to segment IV (*fig. 35s)......................................120

119. Midfemur slender (*fig. 48d) ..................................................................... C. cardosoi Lane, 1942 – Midfemur thick (*fig. 58a) .............................................................................. C. inca Lane, 1939

120. Wing with dark scales basal to midlength band on C, Sc, R 1 and M (*fig. 72d); palpus medium brown (*fig. 14e); all flagellomeres uniformly brown ...... C. atricornis Borkent, 2008 – Wing without any dark scales basal to midlength band other than along posterior margin (*fig. 69k); palpus pale (*fig. 10h); flagellomeres I–VI pale, flagellomeres VII–XIII pigmented ........ ........................................................................................................................ C. pillosa Lane, 1939

121. Forefemur with at least apical 0.3 and midfemur with at least apical 0.3–0.4 paler than bases of fore- and midfemur, respectively (*fig. 48b) ............ C. colombiana Borkent, 2008 – Forefemur uniformly brown (*fig. 47a), with at most, very apex discretely pale and midfemur with, at most, apical 0.2 more pale (*fig. 50b)............................................................122

122. Flagellomeres XII with 2–3 sensilla coeloconica.....................................................................123 – Flagellomeres XII with one sensillum coeloconicum..............................................................124 123. Most of scutum yellow (darker patch anterolaterally), contrasting with darker pleura (*fig. 47a) .................................................................................................... C. briannae Borkent, 2008 – Scutum uniformly dark brown, equal to that of pleura (*fig. 46b) ................................................. ................................................................................................... C. ananacola Dyar, 1926 (in part)

124. Mid and hind tarsomeres 2–4 each banded with darker setae basally and lighter setae apically (*fig. 49d)...................................................................................................................................125 – Mid and hind tarsomeres 2–4 with uniformly pigmented setae (no appearance of any banding) (*fig. 48c)....................................................................................................................................127

125. Wing with dark scales on anterior margin distal to midlength band and on at least apex of R 2, most with additional dark scales in subapical band (*fig. 70l); clypeus with 18–28 setae (*fig. 18u) ............................................................................. C. belkini Borkent, 2008 (in part) – Veins and margin at apex of wing without any dark scales (*fig. 69j); clypeus with 1–4 setae (*fig. 18e)....................................................................................................................................126

126. Midlength wing band with dark scales extending from anterior to posterior margin including on R 4+5 (*fig. 69j); flagellomere I short (*fig. 29f) ................... C. guadeloupensis Borkent, 2008 – Midlength wing band with only pale scales on R 4+5 (*fig. 69l); flagellomere I elongate (*fig. 29h) ......................................................................................... C. aurita Borkent, 2008

127. Hind tibia with basal and apical pigmentation not discrete (*fig. 60b) ........................................ ........................................................................................................... C. dicosimoae Borkent, 2008 – Hind tibia with basal and apical pigmentation discrete (*fig. 48c).........................................128

128. Coronal suture short, extending ventrally about midway along interocular space (as in *fig. 16f); wing with no dark scales distal to midlength band (*fig. 68e) ........................................................ ................................................................................................. C. orthicola Borkent, 2008 (in part) – Coronal suture complete, reaching anteroventral margin of interocular space ( Fig. 9A–B ); wing with apical band of darker scales ( Fig. 9J ) .................. C. fuscifimbria Amaral & Pinho sp. nov.

129. Clypeus with one seta. Posterior anepisternum with anterodorsal margin narrow. Legs brown, except for apex of hin and foretibiae slightly darker. Abdominal segment VIII uniformly pale (Amaral, Mariano & Pinho 2019: fig. 6b–c) ...... C. cambirela Amaral, Mariano & Pinho, 2019 – Clypeus with three setae. Posterior anepisternum with anterodorsal margin thick. Legs brown, except for trochanters and bases of hind and midfemora pale. Abdominal segment VIII pale at distal third (Amaral, Bello-González & Pinho 2021: fig. 2j–m) ...................................................... ..................................................................... C. stenostyla Amaral, Bello-González & Pinho, 2021

Figures

Fig. 6. Corethrella bifida sp. nov., female adult, allotype (MZUSP). A. Left palpus, lateral view. B. Flagellomeres and pedicel, lateral view. C. Cranial setae, anterior and posterior views, and clypeus in anterior view. D. Thoracic setae, lateral view. E. Hind leg claw and empodium, lateral view. F. Head, anterior view. G. Antenna, lateral view. H. Wing. I. Wing veins. J. Abdomen, lateral view. Scale bars: 0.1 mm.

Fig. 21. Corethrella davisi Shannon & Del Ponte, 1928. A. Adult cranial setae, anterior and posterior views, and female clypeus in anterior view. B. Adult thoracic setae, lateral view. C. Hind leg claw and empodium, lateral view. D. Larval exuvia, ventral view. E. Exuvia of larval head, ventral view, except mandible in dorsal view. F. Pupal exuvia, dorsal view. G. Pupal respiratory organ, dorsal view. H. Pupal methatorax and abdomen, dorsal and ventral views. Scale bars: 0.2 mm.

Fig. 4. Corethrella pindorama sp. nov., female adult, holotype (MZUSP). A. Head in anterior view. B. Cranial setae, anterior and posterior views, and clypeus in anterior view. C. Left palpus, lateral view. D. Flagellomeres, lateral view. E. Flagellomeres and pedicel, lateral view. F. Thorax and legs, lateral view. G. Detail of thorax, lateral view. H. Thoracic setae, lateral view. I. Wing veins. J. Wing. K. Hind leg claw and empodium, lateral view. L. Abdomen, dorsal view. Scale bars: 0.1 mm.

Fig. 10. Corethrella unifasciata sp. nov., female adult, holotype (MZUSP). A. Head, anterior view. B. Cranial setae, anterior and posterior views, and clypeus in anterior view. C. Left palpus, lateral view. D. Antenna, lateral view. E. Pedicel and flagellomeres, lateral view. F. Thorax and legs, lateral view. G. Detail of thorax, lateral view. H. Thoracic setae, lateral view. I. Wing veins. J. Wing. K. Hind leg claw and empodium, lateral view. L. Abdomen, dorsal view. Scale bars: 0.1 mm.

Fig.8.Corethrellapatashosp.nov.,femaleadult, holotype.A.Head, anteriorview.B.Cranial setae,anterior and posterior views, and clypeus in anterior view. C. Left palpus, lateral view. D. Antenna, lateral view. E. Flagellomeres and pedicel, lateral view. F. Thorax and legs, lateral view. G. Detail of thorax, lateral view. H. Thoracic setae, lateral view. I. Wing veins. J. Wing. K. Hind leg claw and empodium, lateral view. L. Abdomen, lateral view. Scale bars: 0.1 mm.

Fig. 9. Corethrella fuscifimbria sp. nov., female adult, holotype (MZUSP). A. Head, anterior view. B. Cranial setae, anterior and posterior views, and clypeus in anterior view. C. Left palpus, lateral view. D. Antenna, lateral view. E. Pedicel and flagellomeres, lateral view. F. Thorax and legs, lateral view. G. Detail of thorax, lateral view. H. Thoracic setae, lateral view. I. Wing veins. J. Wing. K. Hind leg claw and empodium. L. Abdomen, lateral view. Scale bars: 0.1 mm.