Mythenteles silus Evenhuis

Evenhuis, Neal L., 2003, World revision of the microbombyliid genus Mythenteles Hall & Evenhuis (Diptera: Mythicomyiidae), Zootaxa 346, pp. 1-28 : 23-25

Mythenteles silus Evenhuis , sp. n.

( Figs. 11 , 22 , 28, 34)

DIAGNOSIS. Closest in appearance to M. deemingi , sp. n. by virtue of the short proboscis, but can easily be separated from it by the short second antennal flagellomere (less than 1/3 the length of the first flagellomere; about 3/4 the length of the first flagellomere in M. deemingi ), the anepimeron with a spot of yellow color, and the thick labellum (thin in M. deemingi ).

DESCRIPTION. Male. Length: 0.95–1.25 mm. Head. Black; eyes dichoptic, separated at vertex by 1.5 x distance between lateral ocelli; frons depressed medially, yellow to yellow­white; face yellow, tip of oral margin brown; antennae brown; scape minute; pedicel cylindrical, slightly wider than long; first flagellomere ( Fig.11 ) ovoid, length about 1.5 x greatest width; second flagellomere about 1/3 length of first flagellomere, with apical sensillum; occiput and mentum shiny brown; proboscis brown, thick, length slightly longer than head height; labrum sclerotized, stiff, pointed apically, length one­half head height; palpus not evident.

Thorax. Mesonotum and scutellum subshining dark brown to black, with scattered dark hairs; remainder of thorax as in M. deemingi with addition of yellow posterodorsal corner of katepimeron.

Wing ( Fig. 22 ). Hyaline; veins brown; costa ends slightly less than halfway between end of R4+5 and M1; vein Sc incomplete, ending at level about halfway between origin of Rs and end of vein R2+3; origin of vein R2+3 almost perpendicular to Rs; Rs evanescent at connection with R1; R4+5 straight to wing margin, not curved, ending in costa at level before end of vein M1; vein M1 curved basally, then straight toward wing margin; M2 straight to wing margin; crossvein dm­cu closing cell dm present; CuA2 thick along cell dm, thin on apical 2/3 to wing margin; A1 straight to wing margin, not curved or sinuous; fringe of hair on posterior margin of wing rather long.

Abdomen. Dorsum dark brown, with scattered dark hairs; yellow laterally on tergites II–VII, sometimes extending medially as posterior fasciae, especially so on apical tergites; venter paler brown than dorsum, with yellow on posterior portion of segments.

Genitalia (Fig. 28). Gonocoxae higher than wide, ovoid, with finger­like projections on apicoventral surface, with X­shaped sclerotization in dorsal view; gonostylus relatively large, ca. 1/3 length of gonocoxa, bifid apically; epiphallus long, thin, with long thin apodemes connected to aedeagal sheath, upper portion vase­like in ventral view, with bifid apex; aedeagus long, thin, with small aedeagal bulb, aedeagal apodeme shoe­shaped in lateral view, with small lateral vanes; epandrium subrectangular in lateral view, wider than high, with curved pseudosurstylus, cerci small, slightly exerted.

Female. Same as male except as follows: female genitalia ( Fig. 34 ) with vaginal furca U­shaped, with apical processes interrupted medially, medial processes perpendicular to lateral processes; spermathecal reservoir ovate­conical, sclerotized brown; apical spermathecal duct long, thin; sperm pump slightly longer than vaginal furca, flared apically; basal valve not evident, basal duct short, membranous, leading to common duct.

Types. Holotype male and 8 male and female paratypes from UNITED STATES: California: San Bernardino Co: 4 mi. [6.4 km] E of Cushenbury Springs, 7.v.1980, J.C. Hall. Paratypes. MEXICO: Baja California: 1 male, 1 female, Sierra San Pedro Mártir, trail La Joya to La Zanja, 10.vi.1953, P.H. Arnaud, Jr. (CAS). UNITED STATES: Arizona: [Coconino Co:] 1 male, Williams, 7.vi., Barber & Schwarz (USNM). [Cochise Co:] 1 female, Huachuca Mts, Miller Cyn, 4.v.1948, A.L. Melander (USNM). Pima Co: 3 females, Organ Pipe Cactus National Monument, Williams Spr, 15–17.ii.1970, Arnaud (CAS). California: 3 males, 9 females, topotypic, collected with types (BPBM, CAS, UCR, USNM). Alpine Co: 1 male, 1.5 mi. [2.42 km] NE of Red Lake, 25.vii.1955, E.I. Schlinger (UCR). El Dorado Co: 11 females, 2–4 mi [3.2–6.4 km] S of Meyers, 24.vii.1955, E.I. Schlinger UCR). Riverside Co: 1 male, Aguas Caliente Indian Reservation, Palm Cyn, 24.ii.1970, Arnaud (CAS); 1 female, 5 mi [8.1 km] E of Elsinore, R.R. Cyn., 13.iv.1965, C.A. Toschi (UCB); 1 male, 2 females, Elsinore Mts, nr summit on Hwy 74, 24.vi.1964, E.F. Riek & G.I. Stage (UCB); 1 female, Menifee Val, (hills on w end), 1800 ft [548.6 m], 15–30.vi.1980, J.D. Pinto (UCR); 2 females, Ortega Hwy, El Cariso Camp, 26.v.1944, 15.v.1946, Melander (USNM); 1 female, Palm Springs, 15.iii.1955, Melander (USNM). San Bernardino Co: 1 female, nr Adelanto, 23.v.1945, Melander (USNM); 1 female, Barton Flats, 22.vi.1948, Melander (USNM); 1 male, Cajon, 22.v.1945, Melander (USNM); 1 female, Cajon Cyn, 9.v.1944, Melander (UCR); 2 males, 8 females, Camp Angelus, 26–28.v.1947, Melander (USNM); 1 female, Mill Cr. Camp, 20.v.1945, Melander (USNM); 1 female, Morongo Val, 20.iv.1944, Melander (USNM); 1 male, 1 female, Mountain Home, 21.vi.1945, Melander (USNM); 1 female, Oak Grove, 9.v.1945, Melander, on white Ceanothus (USNM); 5 males, 15 females, Sheep Cr. Cyn., 24.v.1945, Melander (USNM); 1 female, South Fork Sta. Ana Riv., 19.vi.1945, Melander, on white Ceanothus (USNM); 1 female, Upper Sta. Ana Riv., 21.v.1947, Melander (USNM); 4 females, Wrightwood, 22.v.1954, Melander (USNM). San Diego Co.: 1 male, Borrego, 5.iv.1949, W.W. Wirth (USNM). Nevada: 1 female, Charleston Mts, Kyle Cyn, 5600 ft [1706.9 m], 4.vi.1944, P.H. Timberlake (UCR); 2 females, Mercury, Nevada Test Site, 6.v.1961, BYU­Atomic Energy Commission Collection (USNM). Holotype male and paratype female deposited in CAS. Other paratypes in USNM, UCR, and BPBM.

Remarks. As in propleuralis , there are numerous individuals of this species that vary in the presence, partial presence, or absence of crossvein dm­cu closing cell dm. Most of the specimens included here in the type series of silus were previously a part of the paratype series of Mythicomyia mutabilis Melander. It should be noted that one specimen with a mutabilis paratype label examined during this study is actually a species (undetermined) of Mythicomyia (Mythicomyia) .

Etymology. The specific epithet derives from the Latin silus = pug­nosed; referring to the short, thick labellum and normally pale­colored proboscis.

Distribution. Mountainous California to Nevada and Arizona and into adjacent areas in Baja California in Mexico. Further collecting may also show it to occur in Sonora, Mexico.

Figures

FIGURES 7 – 12. Mythenteles antennae, diagrammatic to show shapes (all drawn to scale). 7. M. coptopheles Evenhuis, sp. n.; 8. M. deemingi Evenhuis, sp. n.; 9. M. hellenicae Evenhuis, sp. n.; 10. M. hispanicola Evenhuis & Blasco­Zumeta, sp. n.; 11. M. silus Evenhuis, sp. n.; 12. M. wadimurri Evenhuis & Theodor, sp. n.

FIGURES 16 – 23. Mythenteles wings. 16. M. coptopheles Evenhuis, sp. n.; 17. M. deemingi Evenhuis, sp. n.; 18. M. freidbergi Evenhuis, sp. n.;, anal lobe folded over 19. M. hellenicae Evenhuis, sp. n.; 20. M. hispanicola Evenhuis & Blasco­Zumeta, sp. n.; 21. M. infrequens Evenhuis & Blasco­ Zumeta, sp. n., anal lobe folded over; 22. M. silus Evenhuis, sp. n.; 23. M. wadimurri Evenhuis & Theodor, sp. n.

FIGURES 30 – 35. Mythenteles female genitalia. 30. M. coptopheles Evenhuis, sp. n. 31. M. deemingi Evenhuis, sp. n. 32. M. hellenicae Evenhuis, sp. n. 33. M. propleuralis (Melander); 34. M. silus Evenhuis, sp. n.; 35. M. wadimurri Evenhuis & Theodor, sp. n., redrawn from Theodor (1983).