ABT.8 REVISION OF THE FLY GENUS BELVOSIA ALDRICH 



15. Pollen of second and third abdominal segments gray, that of fourth deep 



golden, strongly contrasting (northern species) 16. 



Pollen of second and third abdominal segments velvet black, that of fourth 



pale golden (Brazil) wiedemanni, new species. 



Pollen not as described 17. 



16. Thorax indistinctly striped, male with orbitals ; front in both sexes translu- 



cent yellow, shining, not pollinose (eastern United States). 



Tinifasciata Robineau-Desvoidy. 



Thorax very distinctly striped; male without orbitals; front much darker 



(Virginia, Maryland) omissa, new species. 



17. Large blackish species; male with large pulvilli 18. 



Moderate-sized species ; male with small pulvilli except possible in vittata 20. 



18. Third abdominal segment wtih broad, deep yellow uninterrupted pollinose 



band matching the fourth and leaving only the apical quarter black 



(Mexico, Brazil) mexicana, new species. 



Third segment not as described (compare canalis also) 19. 



19. Third abdominal segment with very narrow basal pollinose band ; male with 



outer forceps brown, not swollen (Mexico, Costa Rica; analis of authors). 



ciliata, new species. 



Third abdominal segment with interrupted pollinose band covering basal 



half; male with outer forceps yellowish except at tip, distinctly swollen 



(South America, Panama, West Indies) ciliata var. formosa, new. 



20. Thorax very distinctly striped ; third antennal joint of male very long, seven 



or eight times the second (Paraguay) vittata, new species. 



Thorax indistinctly striped ; third antennal joint not so long 21. 



21. Third antennal joint red, hairs of cheeks pale yellow (Brazil). 



frontalis, new species. 

 Third antennal joint black, hairs of cheeks blackish but delicate (Brazil). 



elusa, new species. 



22. Third abdominal segment with complete dense golden pollinose band cover- 



ing all but the apical fourth or fifth, which is black 23. 



Third abdominal segment wholly golden pollinose to the apex on the sides, a 

 narrow hind margin along the middle of the dorsum black (Alberta, 

 Middle West) canadensis Curran. 



Third abdominal segment with narrower or distinctly interrupted cross- 

 band 27. 



Third segment entirely black, the only pale pollen being on the fourth 

 (Brazil, Venezuela) leucopyga Van der Wulp. 



23. Cheeks with very thin pollen, the black ground color showing through ; para- 



frontals shining black (Manitoba, Illinois, Kansas) splendens Curran. 



Cheeks with dense white pollen 24. 



24. Front calypter blackened, frequently the hind one also; wings blackish; 



very large forms 25. 



Front calypter white or barely yellowish; wings brown; not so large 26. 



25. First and second abdominal segments with three pairs (rarely two) of 



median marginals ; male with front pulvilli long, much longer than last 

 tarsal joint. The largest species of all (United States, mostly northeast). 



borealis, new species. 

 First and second abdominal segments with only a single pair each of median 

 marginals ; male with front pulvilli short, not equalling last tarsal joint 

 (if with long pulvilli see mexicana) (United States, Guatemala). 



bifasciata Fabricius. 



