Bacchini
Creators: name: Thompson, F. Christian
name: Skevington, Jeffrey H.
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Syrphidae

description: Key to the world genera of the Bacchine and Melanostomine groups
A. Postpronotum pilose (Fig. MND 64) or if postpronotum bare, then face and/or scutellum at least partially yellow................................................................................................... other Syrphidae - Postpronotum bare; face usually and scutellum entirely black................................................... 1
1. Abdomen elongate to oval, as broad as or broader than thorax.................................................. 4
- Abdomen petiolate, at its narrowest (usually 2nd tergum apex), distinctly narrower than thorax........................ 2
2. Arista pilose, with pili much longer than aristal width; abdomen slightly petiolate, with 2nd tergum narrowed apically and distinctly narrower than 3rd tergum and thorax; hind tibia modified....................................... Spazigaster
- Arista bare or at most pubescent, with pili only as long as or slightly longer than basal diameter of arista; hind tibia unmodified .................................................................................................... 3
3. Face with distinct tubercle (Fig. MND 7); metathoracic pleuron bare; scutellum without ventral fringe (not Neotropical).................................................................................................... Baccha
- Face without tubercle, straight or convex; metathoracic pleuron pilose; scutellum with ventral fringe (Neotropical only)............................................................................................... Leucopodella
4. Metacoxa bare posteriorly; mesocoxa bare posteriorly......................................................... 7
- Metacoxa with a tuft of pile at posteromedial apical angle (Fig. MND 77); mesocoxa pilose posteriorly................. 5
5. Metepisternum with several fine subappressed hairs; katepisternum with pile patches broadly separated posteriorly, joined anteriorly.................................................................................. Xanthandrus
- Metepisternum bare; katepisternal pile patches broadly separated throughout...................................... 6
6. Metafemur swollen; antennal pits continuous (Afrotropical only)......................................... Pelloloma
- Metafemur slender; antennal pits separated (Neotropical only)............................................ Talahua
7. 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; male legs slender, without bristles, pile tufts or modified hairs............................................. Melanostoma
- Metasternum entire (cf. Fig. MND 71); face variable, almost straight with weak tubercle or moderately or strongly produced forward ventrally; male sometimes with legs modified, either broadened, or with special bristles, pile tufts or modified hairs .................................................................................................... 8
8. Face not greatly produced anteriorly; basoflagellomere oval or slightly elongate, never more than twice as long as broad... 11
- Face produced greatly anteriorly, usually extending well anterior to antennal base; antenna elongate, as long as or longer than face; basoflagellomere elongate, 4 or more times as long as broad............................................... 9
9. Eye pilose; basoflagellomere elongate, more than 5 times as long as broad; male dichoptic............ Pseudoplatycheirus
- Eye bare; basoflagellomere shorter; male holoptic........................................................... 10
10. Eye normal; gena and ventral occiput small, not enlarged; anterior tentorial pit shallow; facial stripe narrow (Neotropical (Andes)).............................................................................. Tuberculanostoma
- Eye reduced; gena and ventral occiput enlarged; anterior tentorial pit deep; facial stripe broad (Palaearctic (Pamirs))............................................................................................" Tuberculanostoma "
11. Male proleg usually modified, with protibia apically and probasitarsomere expanded, or profemur or protibia with specialized chaetotaxy (Holarctic & Neotropical (Andean))............................................................. 13
- Male legs simple (Neotropical or Afrotropical)............................................................. 12
12. Face with transverse grooves dorsally along tubercle; facial tubercle low dorsally, not distinct; antennal pits separated (Neotropical)................................................................................... Argentinomyia
- Facial tubercle distinct dorsally, without grooves; antennal pits confluent (Afrotropical)...................... Afrostoma
13. Mesonotum smooth or with puncta finer and more widely scattered, not producing a distinct rugose appearance; legs partially pale.................................................................................. Platycheirus ... 15
- Mesonotum distinctly and finely rugose; rugose appearance due to large and closely set puncta, puncta set in irregular rows; legs black........................................................................................... 14
14. Arista bare, inserted near middle of basoflagellomere; face wider ventrally, with sides divergent ventrally; abdomen with pale maculae.................................................................................. Rohdendorfia
- Arista pubescent, with short, appressed pile, inserted basally; face not distinctly wider ventrally, with sides approximately parallel; abdomen entirely black................................................................ Syrphocheilosia
15. Wing shorter than abdomen; abdomen broad or mostly red or black with 2 yellow maculae on 3rd tergum...... Pyrophaena
- Wing longer than abdomen; abdomen narrow, not with such abdominal pattern.................................... 16
16. Male: Protibia apically and/or protarsus expanded, usually with specialized setae; profemur without specialized chaetotaxy........................................................................................ Platycheirus (s.s.)
- Male: Protibia and protarsus simple...................................................................... 17
17. Male: Profemur posteriorly on at least apical 1/2 with row of stiff straight black setae, with apical-most (last) seta longer and with its apex strongly curved.................................................................. Pachysphyria
- Male: Profemur without such specialized chaetotaxy......................................................... 18
18. Face produced ventrally, pollinose with distinct bare puncta; male protibia usually with long black bristles proteriorly (Holarctic and Andean).............................................................................. Carposcalis
- Face not produced, without distinct bare puncta; male protibia without such specialized chaetotaxy (New Zealand only)................................................................................................ Eocheilosia
description: Published as part of 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, pp. 97-114 in Zootaxa 3847 (1) on pages 102-103, DOI: 10.11646/zootaxa.3847.1.5, http://zenodo.org/record/4928795