28 DIPTEEA. 



Eyes glabrous. 



Abdomen with a double spot of a lighter colour on dark ground on the 

 second segment. 



Segments 3-5 of the abdomen red 4. relicta, sp. n. 



Segments 3-5 of the abdomen not red. 



Front femora and tibiae red 5. coarctata, Macq. 



Front femora and tibiae black 6. illucens, Linn. 



Abdomen without the double spot of a lighter colour on the second segment. 



Wings unicolorous, yellowish 7. formica, sp. n. 



Wings darker at the apex 8. pterocausta, sp. n. 



1. Hermetia aurata. 



Hermetia aurata, Bellardi, Saggio &c. i. p. 27 , t. 1. f. 8 \ 

 Hermetia chrysopila, Loew, Centur. x. p. 11. 



Hab. North America, Texas. — Mexico, Northern Sonora {Morrison), Morelia (de 



Saussure 1 ). 



In the single specimen from Sonora the first two abdominal segments show only 

 traces of golden pile ; on the second segment a narrow cross-band of such pile becomes 

 visible near the anterior margin in an oblique light only ; the third segment has a 

 similar cross-band, and its posterior portion is densely clothed with golden pile, but 

 the interval is black. Instead of " abdomen prseter segmentorum singulorum angulos 

 posticos" I would read " anticos " in Loew's description : with this alteration I have but 

 little hesitation in referring our specimen to H. chrysopila (=E. aurata, Bell.). Both 

 Bellardi and Loew have omitted to mention that the eyes of this species are densely 

 hairy : revived on wet sand they showed, on bluish-green ground, two deeply indented 

 zigzag purplish lines running from top to bottom, and between the two a stripe of the 

 same colour, expanded in the middle, and bearing an eye-like blue spot on the expan- 

 sion. The types in Prof. Bellardi's collection are larger, and have more golden pile on 

 the second segment ; nevertheless I believe them to be the same species. 



2. Hermetia comstocki. (Tab. I. fig. 3.) 



Hermetia comstocki, Willist. Canad. Entom. 1885, p. 125. 



Eyes pubescent; wings brown, with a longitudinal hyaline cuneiform stripe, which begins in the third 



posterior cell, and runs towards the anal angle, where it becomes much broader ; thorax and abdomen 



aureo-tomentose. 

 Length 10-14 millim. 



Hab. North America, Arizona (ComstocJc).— Mexico, Northern Sonora (Morrison). 



Face, front, and vertex brownish-red, with brownish spots, sometimes altogether brown, 

 with some reddish spots ; face of a purer yellow in the middle ; a narrow border of 

 yellowish-silvery hairs along the eyes; ocellar tubercle brown; occiput black; first 

 two joints of the antennae, and a portion of the third, yellowish-red, the rest black. 



