OF pniLADELPniA. 61 



edge ; tergum brilliant silvery at tip, and with a white fascicle 

 each side at base. 



Length seven-twentieths of an inch. 



I am indebted to Mr. August G. Oemlcr, of Savannah, for thie 

 fine species. It belongs to Wiedemann's fifth division. 



'^. A. ALTERNATA. — Body villous, above black, beneath and 

 sides cinereous; tergum fasciate with cinereous. . 



Inhabits the United States. 



Head black ; eyes chestnut ; front, beneath the antenna) bright 

 cinereous ; proboscis concealed in a groove to the tip ; palpi dis- 

 tinct, exterior ; thorax cinereous, tinged with fulvous each side, 

 and at the scutellar suture ; wings dusky, pellucid, nervures [46] 

 bli" kish-brown ; base to the first transverse nervures brown opa- 

 que ; pectus cinereous; feet blackish ; scutel edged with cinereous; 

 abdomen each side with dense long hair, which is cinereous on 

 the first and second segments, but on the remaining segments 

 alternating with black ; tergum with six or seven cinereous 

 lineolar bands; venter cinereous ; segments, particularly the third, 

 bkvk at base. 



Length of body more than eleven-twentieths of an inch. 



Found in Pennsylvania, and also in Missouri. It belongs to 

 Wiedemann's fifth tribe. 



G. A. IRRORATUS. — Black; wings hyaline, with numerous 

 black punctures. 



Inhabits the Rocky Mountains. 



Body deep black, hairy; eyes reddish-brown, tinged with 

 golden ; wings hyaline, with numerous irregular, unequal, dark 

 fiiscous spots, of which those near the costal margin are larger 

 than those near the posterior margin and tip, the spots along the 

 costal margin are quadrate and alternate somewhat regularly with 

 their hyaline intervale. 



Length one-fourth of an inch. 



The nervures of the wings are nearly similar to those of the 

 wing, fig. 22, pi. 17 of Meigen's Diptera Europea. — (Europiiis- 

 chen zweifliigeligen.) 



[This is A. adipus Fabr. ; A. irrorata Macq., is a different in- 

 sect. — Sacken.] 

 1823.] 



