138 Mr. F. Walker's Characters of undescrihed Diptera 



groups ; a few of them appear also in North Africa and West 

 Asia, one in North America, and one in Hindostan. The group 

 Exoprosopa, which comprises most of the species of Anthrax in 

 warm regions, appears along the south-east and south borders of 

 Europe. 



NORTH AMERICA 



Contains about forty described species, which form seven 

 groups. 



MEXICO. 



Some of the North American species extend to Mexico, besides 

 which it is inhabited by nine species and five groups. 



WEST INDIES. 



Five groups and fourteen species, two of which also inhabit 

 Brazil, and one is said to have been found in New Guinea. 



SOUTH AMERICA. 



Ten groups and fifty-five species. 



Group 3. Dipt. Saund. 1G6. 

 Anthrax convexa. 



Picea, capite argenteo, antennis pedibusque nigris, thorace 



fulvo-piloso, scutelli margine ferrugineo, abdomine fasciis 



duabus albidis, fasciculis duobus basalibus, apice argentea, 



femoribus fulvis, alis cinerascentibus, basi costaque fuscis. 



Piceous ; head silvery ; proboscis and antennae black; thorax 



with tawny hairs in front and along each side ; scutellum with a 



ferruginous border ; abdomen with slight whitish bands, one near 



the base more distinct than the otliers, a tuft of white hairs on 



each side at the base, tip silvery ; legs black, femora mostly 



tawny ; wings greyish, brown at the base and along three 



quarters of the costa. 



Length of the body 4 lines ; of the wings 10 lines. 

 Valley of the Amazon. 



Anthrax dorsalis, 



Testacea, thoracis disco nigro, scutello fulvo, abdomine fasciis 

 tribus contiguis nigris, alis dimidio basali fusco testaceo-notato 

 incisuris quatuor. 



Testaceous ; disk of the thorax black ; scutellum tawny ; 

 abdomen with three short contiguous black bands ; wings brown. 



