syrphine

Thompson, F. Christian & Skevington, Jeffrey H., 2014, Afrotropical flower flies (Diptera: Syrphidae). A new genus and species from Kenya, with a review of the melanostomine group of genera, Zootaxa 3847 (1), pp. 97-114 : 101-102

Key to the genera and subgenera of Afrotropical syrphine flower flies

A. Postpronotum pilose (Fig. MND 64); male abdomen with tergum 5 not visible dorsally (Fig. MND 101) (subfamilies Microdontinae & Eristalinae ).................................................................... other flower flies - Postpronotum bare (Fig. MND 65); male abdomen with tergum 5 visible dorsally (Fig. MND 97) (subfamily Syrphinae ).... 1

1. Tergum 1 greatly reduced, frequently almost linear on disc and practically covered by scutellum, sublaterally at most 1/2 as long as tergum 2 (Fig. MND 96); terga not punctate; length 6.7 mm or more....................................... 5

- Tergum 1 well-developed, especially on disc where it is frequently 1/2 as long as tergum 2 and always extends well beyond scutellum, sublaterally about 3/4 as long as tergum 2 (Fig. MND 97); terga minutely punctate; length 7.5 mm or less................................................................................................... Paragus ...2

2. Eye with pile of nearly uniform color, not forming vittae of contrasting color; scutellum entirely black... Pandasyopthalmus

- Eye with pile arranged in 2–5 more or less vertical vitta or contrasting color; scutellum black with apex narrowly yellow or reddish.............................................................................................. 3

3. Scutellum with conspicuous dentis (teeth) on posterior margin; eye in dorsolateral view with two dark and three more distinct white pile fasciae.......................................................................... Serratoparagus

- Scutellum with apical margin simple, without dens; eye with two white pile fasciae among dark pile.................... 4

4. Terga 1–5 completely fused, at least laterally...................................................... Afroparagus

- Only terga 1–2 fused completely................................................................... Paragus

5. Abdomen parallel-sided (Fig. MND 96) to oval, never distinctly petiolate......................................... 7

- Abdomen elongate, strongly petiolate (Fig. MND 95); 2nd tergum narrower than 3rd tergum.......................... 6

6. Laterotergum pilose, at least with a patch of long pile dorsally; postpronotum and/or anterior anepisternum pilose; metepisternum pilose; scutum usually with a well-develop collar of longer pile on anterior margin...................... Allobaccha

- Laterotergum, anterior anepisternum, metepisternum all bare; scutum without pile collar........................................................................................................................ Pseudodoros *** Baccha in our sense does not occur in the Aftropical region, but would run here in this key and is separate from the preceeding genera by a complete metacoxal bridge.

7. Face and scutellum entirely black in background color; abdomen usually without marginal sulcus; metasternum bare; eye bare. Note that one Pelloloma species has an indistinct marginal sulcus on the apical tergum 5............................ 22

- Face or scutellum or both at least partly yellow or yellowish brown in background color, both never entirely black, if in doubt, eye pilose; abdomen, metasternum, and eye variable.......................................................... 8

8. Antenna short, shorter than head; basoflagellomere at most twice as long as broad; scape and pedicel not longer than broad (Fig. MND 7–8)...................................................................................... 10

- Antenna elongate, longer than head; basoflagellomere at least three times as long as broad; scape or pedicel longer than broad (Fig. MND 4)......................................................................................... 9

9. Metafemur and metatibia without pile brushes; eye densely long pilose; scape and pedicel subequal; abdomen strongly convex dorsally, strongly margined; vein R 4+5 sinuate, looped into cell R 4+5; calypter bare......................... Chrysotoxum

- Metafemur and metatibia with brushes of long pile; eye sparsely and short pilose; scape about 3 times as long as pedicel; abdomen not convex nor with marginal sulcus; vein R 4+5 straight; calypter pilose on ventral lobe.................. Afrosyrphus

10. Calypter with lower lobe pilose, especially on posteromedial portion (Fig. MND 62); metacoxa with a tuft of strong pile at posteromedial apical angle (Fig. MND 77)........................................................... Betasyrphus

- Calypter bare; metacoxa without pile tuft.................................................................. 11

11. Anterior anepisternum bare; wing margin without minute closely spaced black maculae on posterior margin............. 13

- Anterior anepisternum pilose at least posterodorsally (Fig. MND 65); wing margin with a series of minute closely spaced black maculae on posterior margin (Fig. MND 61)............................................................... 12

12. Metasternum pilose; metepisternum pilose ventrad to spiracle......................................... Episyrphus

- Metasternum bare; metepisternum bare............................................................ Meliscaeva

13. Abdomen without marginal sulcus....................................................................... 19

- Abdomen with at least a weak marginal sulcus on terga 4 and 5, often with a strong sulcus on terga 3–5................ 14

14. Metapleuron bare ventrad to spiracle; metasternum variable; size and shape variable............................... 16

- Metapleuron with a tuft of fine pile ventrad to spiracle; metasternum pilose; large species with broad flattened abdomens with distinct marginal sulcus................................................................................ 15

15. Mesonotum anteriorly with a distinct collar of longer and denser pile; vein R 4+5 sinuate, distinctly looped into cell R 4+5 ................................................................................................... Asarkina

- Mesonotum without a collar of pile; vein R 4+5 nearly straight........................................... Achoanus

16. Eye densely pilose; metacoxa with tuft of strong pile at posteromedial apical angle (Fig. MND 77)............ Betasyrphus

- Eye bare; metacoxal without such a pile tuft............................................................... 17

17. Metasternum pilose; wing densely microtrichose on apical 1/3; scutum dark laterally; male metacoxa simple...... Eupeodes

- Metasternum bare; wing extensively bare, with only sparse scattered microtrichia on apical 1/3...................... 18

18. Scutum with well-defined bright yellow lateral vitta, extending from postpronotum to scutellum; male metacoxa with ventral spine-like process (widespread)................................................................... Ischiodon

- Scutum with ill-defined yellow lateral vitta; male metacoxa simple (northern Chad only)........................ Scaeva

19. Scutum with lateral yellow vitta extending from postpronotum to scutellum...................................... 21

- Scutum with lateral yellow vitta not extending beyond transverse suture......................................... 20

20. Face with broad black vitta; subscutellar fringe well-developed except on medial 1/3; male genitalia small, with tergum 9 at most 1/2 as wide as abdomen; female 5th tergum with distinct yellow maculae which are isolated from lateral margins................................................................................................. Exallandra

- Face yellow; subscutellar fringe absent; male genitalia large and globose, with tergum 9 as wide as abdomen; female 5th tergum either without yellow maculae or yellow maculae broadly reaching lateral margin.............. Sphaerophoria (s. s.)

21. Subscutellar fringe complete, dense; male holoptic; male genitalia small, inconspicuous, with tergum 9 at most 1/2 as wide as abdomen; female face without carina (widespread, but not St. Helena).................................... Allograpta

- Subscutellar fringe absent; male dichoptic; male genitalia large and globose, with tergum 9 as wide as abdomen; female face with a distinct median carina extending from antenna to tubercle ( St. Helena only)......... Sphaerophoria (Loveridgeana)

22. Metepisternum with some fine subappressed pile; katepisternum with pile patches broadly separated posteriorly, joined anteriorly (Fig. MND 42); metacoxa with tuft of pile at posteromedial apical angle (as in Fig. MND 48)................................................................................................ Xanthandrus (Afroxanthandrus)

- Metepisternum bare; katepisternal pile patches broadly separated throughout (as in Fig. 45); metacoxa with or without pile tuft ................................................................................................... 23

23. Metacoxal with tuft of pile at posteromedial apical angle (as in Fig. MND 48); metafemur swollen, usually about 3 times as broad as tibia; metasternum entire................................................................. Pelloloma

- Metacoxa without posteromedial apical pile tuft; metafemur simple, not swollen, about as broad as tibia................ 24

24. Metasternum greatly reduced, with deep posterior incision laterally so that sclerotized portion consists of a median diamond-shaped area with narrow anterior and lateral strips (Fig. MND 70); face not produced below, with small tubercle (Fig. MND 8)................................................................................... Melanostoma

- Metasternum entire (Fig. MND 71); face almost straight with strong tubercle ( Fig. 1B ), slightly produced forward ventrally.............................................................................................. Afrostoma

Figures

FIGURE 1. Afrostoma quadripunctatum Skevington & Thompson, male (specimen USNM ENT 00036401). A. habitus, dorsal view; B. oblique view of head; C. habitus, lateral view. Scale bars: 1 mm.