020 list of diptera. 



16. Erax ambiguus. 



Niger ; thorax cinereus vittis nigris ; abdomen fasciis albidis, 

 ano brevi ; pedes testacei, femoribus subtus nigris ; aUe sub- 

 fiavescentes. 



Erax ambiguus, Macq. Dipt. Exol. Suppl. 1, 84, 34. 



Texas. Merida de Yucatan. 



17. Erax Dascyllus. 

 Asilus Dascyllus, Cat. of Diptera, Pt. 2, 401. 



18. Erax notabilis. 



Mas. Ater ; abdominis latera et venter cinerea, segmenta duo 

 apicalia albida ; pedes riifi ; alee snbrufescentes, dilatattc ; 

 furca cubitalis antica ramulo nullo. 



Erax uotabilis, Macq. Dipt. Exot. i. 2, 110, 6, pi. 9, f. 8. 



North ? America. 



19. Erax argyrogaster. 



Thorax cinereus, vittis nigris ; abdomen argentum, maculis dorsa- 

 libus nigris ; pedes testacei ; alee subfiavescentes. 



Erax argyrogaster, Macq. Dipt. Exot. Suppl. 1, 84, 35. 



Merida, Yucatan. 



Mexico. 



Group 1. 



Corpus longe et dense pilosum. Facies valde convexa. Mys- 

 tax densissimus. Proboscis robusta, lauceolata. Thorax gibbosus, 

 carina hirsutissima. Pedes validi, birti, spinosi. Mas. — Abdomen 

 alas ncn superans. Sexualia maxima. Fcem. — Abdomen alas longe 

 superans, triente apicali stylata. 



Cubital vein forked at very much beyond half its length ; forks 

 slightly curved, converging towards each end ; fore fork forming at 

 its base an obtuse angle, wbicb emits no branch. First and second 

 externo-medial veins nearly straight ; third very slightly curved, 

 forming a sligbtly obtuse angle with the prsebrachial, joining the 

 fourth far from the border. Subanal joining the anal at a short 

 distance from the border. Male. — Wings dilated in front towards 

 the tips ; dilated part ribbed transversely. 



