Asiobaccha Violovitsh
Creators: name: Mengual, Ximo
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Syrphidae
Asiobaccha

description: Key to the species of Asiobaccha Violovitsh    
1. Alula broad or reduced but always present (Figures 1, 3a, 8a).................................... 4  
 – Alula absent, anal lobe reduced (Figure 9d).......................................................................... 2   
 2. Cell C almost completely bare, microtrichose on apical 1/5. Face with white pollinosity (Figure 10f). Abdomen dark; tergum 1 dark (Figure 10a, b) (New Guinea)................................................................................................................... A. selsi Mengual sp. nov.   
 – Cell C entirely microtrichose. Face with yellow pollinosity (Figure 9f). Abdomen black with yellow markings on terga 2 and 3, sometimes also on tergum 4 (Figures 6c, 9c, d); tergum 1 usually yellow, not always.................................................................... 3   
 3. Pleuron dark: meron, metaepisternum and metacoxa dark brown (Figure 9d). Metatibia yellow-brown (Figure 9c, d). Scutellum unicolor, between yellow-brown to black (Taiwan, Vietnam, Sulawesi and Luzon)............................ A. sauteri (Kertész)   
 – Pleuron lighter: meron, metaepisternum and metacoxa yellow (Figure 6d). Metatibia yellow with medial broad, black annulus (Figure 6c, d). Scutellum yellow with medial dark area (Sumatra and Malay Peninsula)...................................................................................................................................... A. maculosa Mengual & Thompson sp. nov.   
 – [Note: A. maculosa has a narrow, linear alula but it is absent in all the paratypes; A. sauteri has no alula. This species is keyed out in couplets 3 and 8]   
4. Scutellum yellowish (Figures 5c, 10c). Abdomen usually with yellow or orange markings (Figures 5c, 7a, 10c). Face bright yellow (Figures 5e, 8e)............................ 7  
 – Scutellum and abdomen entirely black (Figures 3c, 8c). Face variable: black to dark yellow (Figures 3f, 8f)....................................................................................................................... 5   
 5. Metatarsi yellowish white, except metabasitarsomere dark on basal 1/5 (Figure 3c, d). Alula mostly bare, microtrichose only on anterodistal quarter, narrower than cell BM (Solomon Islands).......................................................................... A. albipeza Mengual sp. nov.   
 – Metatarsi dark, black or dark brown (Figures 8d, 9b). Alula microtrichose on apical half or more, as broad as or broader than cell BM............................................................ 6   
 6. Cell BM bare on basal half or more, cells R and CuP bare basally, costal cell bare on basal half or less (Vanuatu, New Caledonia, Fiji, Tonga)................ A. praefica (Bezzi)   
 – Wing entirely microtrichose except alula bare very basally (Samoa).................................................................................................................................. A. samoaensis Mengual sp. nov.   
7. Scutellum variable, usually entirely yellow or dark brown, never with a medial, round black macula. Tergum 4 different................................................................................. 9  
 – Scutellum yellow with a medial, isolated dark/black macula surrounded by yellow (Figure 11a). Tergum 4 with two longitudinal yellow vitta reaching anterior margin (Figure 11a)........................................................................................................................................... 8   
 8. Alula broad, broader than costal cell. Tergum 3 with a submedial, triangular yellow fascia, not divided medially (Figure 11a). Male: Frontal triangle densely yellow pollinose dorsally (Figure 12f). Female: frons yellow pollinose on dorsal 3/4 (between anterior ocellus and antennal base), laterally joining pollinosity of face; and ocellar triangle shiny (Figure 11e) (Borneo, Malay Peninsula, Sumatra, Java, Vietnam).................................................................................................. A. tinctiventris (Meijere)   
 – Alula narrow, as narrow as or narrower than costal cell (Figure 6c). Tergum 3 with two broad yellow maculae, not medially joined (Figure 6c). Male: Frontal triangle shiny, not pollinose (Figure 6f). Female: frons yellow pollinose only on dorsal 1/2 or less (between anterior ocellus and antennal base), isolated from facial pollinosity; and ocellar triangle pollinose (Figure 12e) (Sumatra and Malay Peninsula)............................................................................................. A. maculosa Mengual & Thompson sp. nov.   
9. Mesonotal fringe or collar absent on anterior part of scutum (Figures 4d, 10e). Alula narrower than costal cell, at most as broad as costal cell (Figure 14c, d)............. 17  
 – Mesonotal fringe or collar well-defined on anterior part of scutum (Figures 3b, 4b). Alula usually broader than costal cell in the apical part (Figure 14a, b)................ 10 [NOTE: A. tinctiventris has no mesonotal collar but alula broader than costal cell. This species is keyed out in couplets 7 and 8]   
 10. Wing entirely microtrichose, except alula bare on posterior margin (Figure 3a, b) (Solomon Islands).................................................... A. aea Mengual & Thompson sp. nov. – Wing bare basomedially; cell BM bare basally (Figures 4a, 5c)................................... 11   
11. Abdominal tergum 1 black or brownish, sometimes yellowish on lateral margins (Figure 4a); tergum 2 black with two pairs of yellow maculae: one basally, which may join medially, and another medially; tergum 3 with two triangular maculae or with a broad yellow fascia not reaching anterior margin (Figures 4a, 8a)............. 14  
 – Abdominal tergum 1 yellow with or without narrow dark fascia on posterior margin (Figure 12a); tergum 2 yellowish, brownish posteriorly, with a dorsomedial brownish macula; tergum 3 with broad yellow fasciate maculae reaching anterior margin (Figures 5c, d, 7c)............................................................................................................. 12 [Note: A. virtuosa does not totally comply with any options of the couplet 11, as it has tergum 1 yellow, but yellow macula on tergum 3 does not reach anterior margin. For this reason, it appears twice in the key]   
 12. Cell R entirely microtrichose posterior to spurious vein (Figure 14b). Tergum 4 with two subtriangular/rectangular yellow maculae, isolated from anterior margin (Figure 12a, b).............................................................................................. A. virtuosa (Curran)   
 – Cell R bare basally, posterior to spurious vein. Tergum 4 black, or with yellow markings reaching anterior margin (Figures 5d, 7c)........................................................ 13   
 13. Abdominal tergum 4 black, sometimes with two diffuse round yellow maculae on anterior margin; tergum 5 black (Figure 5c, d). Stigma brown, not contrasting with colouration of subcostal cell or cell R1 (Figure 5d) (New Guinea)........................................................................................................................................... A. doesburgi Mengual sp. nov.   
 – Abdominal tergum 4 black with a broad yellow fascia on anterior 1/2, slightly emarginated medially on posterior margin; tergum 5 black with two basal elongate yellow maculae on anterior margin (Figure 7c, d). Stigma darker, contrasting with subcostal cell and cell R1 (Figure 7c) (Australia)............................................................................................................................................ A. notofasciata Thompson & Mengual sp. nov.   
 14. Abdominal tergum 4 black with two subtriangular/rectangular yellow maculae, broadening laterally and not reaching the lateral margin, on basal half of the tergum (Figure 12a); golden yellow pollinosity on posterior anepisternum, katepisternum and katatergum; cell R entirely microtrichose posterior to spurious vein (Figure 14b) (Malay Peninsula, Sumatra and Borneo).................. A. virtuosa (Curran)   
 – Abdominal tergum 4 black, at most with two round very small yellow maculae on the anterolateral margin of the tergum (Figures 4a, 8a, 12c); white or golden pollinosity on posterior anepisternum, katepisternum and katatergum; cell R bare on basal 1/3 or more, posterior to spurious vein (Figure 14a).................................... 15 [NOTE: Some specimens of A. nubilipennis from Sumatra have the cell R almost entirely microtrichose, although they have tergum 4 black and key out to couplet 16]   
 15. Metatarsus entirely black; scutellum black, sometimes posterior margin tawny (Figure 4a, b) (Philippines)............................ A. aquila Thompson & Mengual sp. nov.   
 – Metatarsus pale (white-yellow), except metabasitarsomere black on basal 2/3; scutellum yellow-brown (Figures 5a, 8b).............................................................................. 16   
 16. Abdominal tergum 3 with two medial subtriangular yellow maculae, pointing anteriorly and not reaching lateral margins; metafemur mostly dark brown; pleuron with yellow golden pollinosity (Figure 5a, b) (Sumba).......... A. bimaculata (Keiser)   
 – Abdominal tergum 3 with medial broad yellow fascia (about 1/3 to 1/2 of tergum length) reaching lateral margins, sometimes also with two laterobasal small yellow maculae (Figures 8a, 12c); metafemur yellow with medial dark annulus (Figure 8b); pleuron with white or yellow pollinosity (widely spread: from Sri Lanka, India to Japan, south to Indonesia).............................................................. A. nubilipennis (Austen)   
 17. Scutum, scutellum, pleuron and legs yellowish orange; abdomen mostly yellowish orange basally (Figure 10c). Male genitalia large, with epandrium and hypandrium enclosed under sternum 4 (Figure 10d) (Solomon Islands)............................................................................................................................................................. A. taronja Mengual sp. nov.   
 – Scutum darker dorsally, scutellum yellowish (Figure 11c), pleuron yellow with two black vittae (from dorsomedial anepimeron to mesocoxa and on metaepisternum) and legs partly yellow (Figure 7b). Male genitalia small, epandrium and hypandrium exposed and not covered by sternum 4................................................................. 18   
 18. Abdominal tergum 4 black on posterior 2/5 with yellow fascia on anterior 3/5, emarginate posteromedially and broadening laterally (Figure 7a); antennal base with lateral lobular expansions on each side (Figure 1) (Sulawesi)........................................................................................................................................... A. marissae Mengual sp. nov.   
 – Abdominal tergum 4 entirely black, sometimes with purple gloss (Figures 6a, 11c); antennal base normal, without lateral expansions........................................................... 19   
 19. Wing entirely microtrichose: cell BM microtrichose; anal lobe and cell CuP microtrichose (Figure 6a); alula mostly bare (New Guinea, Sumbawa and Luzon)................................................................................................................................................ A. loriae (Meijere)   
 – Wing bare basomedially: cell BM bare on basal 1/5 or more; cell CuP and anal lobe bare basally (Figures 11c, 14c, d); alula mostly bare........................................................ 20   
 20. Cell R entirely microtrichose; cell BM bare on basal 1/3 – 1/2 (Figures 11c, 14d) (Kai Islands, Misool, New Guinea, New Ireland, and Woodlark islands).............................................................................................................................................................. A. tripartita (Walker)   
 – Cell R bare on basal 1/3 – 1/2; cell BM bare on basal 1/2 or more (Figures 4c, 14c) (Moluccas (Maluku and North Maluku Provinces), New Guinea, New Ireland, and Australia)............................................................................................................ A. bicolor (Austen)
description: Published as part of Mengual, Ximo, 2016, A taxonomic revision of the genus Asiobaccha Violovitsh (Diptera: Syrphidae), pp. 2585-2645 in Journal of Natural History 50 on pages 2638-2641, DOI: 10.1080/00222933.2016.1206634, http://zenodo.org/record/3994636