Helina Robineau-Desvoidy, 1830

Michelsen, Verner, 2023, Macaronesian Muscidae (Diptera). IV. The genus Helina Robineau-Desvoidy, and description of the male of Spilogona maderensis Michelsen, Zootaxa 5293 (2), pp. 251-276 : 273

Key to the Macaronesian species and subspecies of Helina Robineau-Desvoidy

1 Meron with fine setulae. Scutellum with setulae beneath lateral setae............................................ 2

- Meron bare. Scutellum bare beneath lateral setae............................................................ 9

2 Vein C dorsally bare. Prealar seta short. Scutellum with setulae along lower lateral margin........................... 3

- Vein C dorsally setulose. Prealar seta long. Scutellum bare along lower lateral margin......... 5. Helina lundbladi Tiensuu

3 Notopleuron without setulae............................................................................. 4

- Notopleuron with setulae around posterior seta........................................... 1. Helina evecta (Harris)

4 Males .............................................................................................. 5

- Females............................................................................................. 7

5 Frons at narrowest point c. same width as anterior ocellus and with contiguous fronto-orbital plates. Hind tibia with 2(‒3) ad setae and 4 av setae, all being shorter than hind tarsomere 2. Abdomen broadly ovoid with distinct paired dark marks on tergites III and IV........................................................................................... 6

- Frons at narrowest point 2.5‒3 times as wide anterior ocellus and with fronto-orbital plates separated by frontal vitta. Hind tibia with ad and av setae abundant and generally longer than hind tarsomere 2. Abdomen slender ovoid, with indiscernible paired dark marks on tergites III and IV …................................................. 4. H. grancanariae sp. nov.

6 Abdomen bluish-black subshining through thin grey pruinosity; paired dark marks on tergites III and IV small, only visible in oblique posterior aspects............................................. 2. H. obscurisquama obscurisquama (Stein)

- Abdomen bronze-black subshining; paired dark marks on tergites III and IV larger and more distinct............................................................................... 3. H. obscurisquama pseudonivalis (Santos Abréu)

7 Abdominal grey pruinosity with a bluish-grey tinge.......................................................... 8

- Abdominal pruinosity with a bronze-grey tinge...................... 3. H. obscurisquama pseudonivalis (Santos Abréu)

8 Dark grey pruinosity of thorax with a brownish hue differing from the bluish tinge of the abdominal pruinosity............................................................................. 2. H. obscurisquama obscurisquama (Stein)

- Dark grey pruinosity of thorax with a bluish tinge similar to that of the abdomen.............. 4. H. grancanariae sp. nov.

9 Hind tibia without pd seta(e). Dorsocentral setae 2 + 3....................................................... 10

- Hind tibia with a short, but distinct pd seta in basal third..................................................... 12

10 Longest aristal branches at least two-thirds as wide as width of postpedicel. Scutellum and abdomen in part translucent ochre brown to yellow. Katepisternal setae 2 + 2................................................................. 11

- Longest aristal branches c. one-third as wide as width of postpedicel. Body wholly dark. Katepisternal setae 1 + 2......................................................................................... 6. H. rufitibialis Hennig

11 Larger, wing length normally 6.5‒8.0 mm. Mesonotum with 1 st postsutural pair of dorsocentral setae inserted outside median brownish black mark …................................................................7. H. clara (Meigen)

- Smaller, wing length normally 5.0‒ 6.4 mm. Mesonotum with 1 st postsutural pair of dorsocentral setae inserted on a pair of submedian brownish black marks................................................. 8. H. sexmaculata (Preyssler)

12 Dorsocentral setae 2 + 3............................................................................... 13

- Dorsocentral setae 2 + 4.............................................................................. 14

13 All femora extensively ochre yellow. Male frons narrow, contiguous fronto-orbital plates without orbital setae. Vein C bare on dorsal surface..................................................................... 12. H. vilissima Hennig )

- All femora extensively black. Male frons with a broad, deep brown frontal vitta and 2 reclinate orbital setae on fronto-orbital plate. Female with vein C setulose dorsally in distal two-thirds (these setulae less regular or even absent in the male)...................................................................................... 13. H. atlantica (Tiensuu)

14 Longest aristal branches about same length as width of postpedicel. Male: Hind femur without pv setae near middle; sternite V without enlarged pair of setae. Female: Mid and hind femora mainly dark, ochre yellow on less than distal half.......... 15

- Longest aristal branches c. 1.5 times as long as width of postpedicel. Male: Hind femur with 1 pv seta near middle; sternite V with enlarged pair of setae. Female: Mid and hind femora extensively ochre yellow, dark on less than basal third......................................................................................... 11. H. parcepilosa (Stein)

15 Fore tibia with 0 p seta. Paired dark marks on tergites III and IV medium-sized, oval, widely separated from anterior and posterior margins of respective tergites. Male: Abdomen slender ovoid.......................... 9. H. reversio (Harris)

- Fore tibia with 1 p seta. Paired dark marks on tergites III and IV large, subrectangular, almost extending entire length of respective tergites. Male: Abdomen broadly ovoid......................................10. H. santosabreui sp. nov.