OP PHILADELPHIA. 57 



the basal one very short and also obsolete ; feet reddish-brown, 

 tibia pale. 



Length a quarter of an inch nearly. 



Nervures of the wings as in albicornis. 



THEKEVA Meig. 



1. T. tergis[sa]. — Wings spotted ; tergum silvery pruinose. 

 Inhabits East Florida. 



Body blackish ; head blackish-brown, with white hair beneath ; 

 antennas, basal joint cinereous with black hair; palpi pale; pro- 

 boscis dusky; thorax [40] blackish-brown; wings slightly tinged 

 with brownish, and with several brown spots, and brown stigma ; 

 feet pale, dusky at the joints ; tergum dull testaceous, darker at 

 base, and with a bright silvery reflection in a certain position, 

 posterior margins of the segments whit€. 



Length more than seven-twentieths of an inch. 



The reflected color of the tergum is very similar to that of 

 Musca anilis Linn. It seems to be closely allied to T. pictipennis 

 Wied., but is larger, destitute of bands on the wings, and the 

 color of the antennae, feet, &c. is diff^erent. 



[Changed to T. corrusra by Wiedemann. — Sacken.] 



2. T. NIGRA. — Black ; incisures of the tergum and lateral spot 

 on the fifth segment gray. 



Inhabits Pennsylvania. 



Head glabrous, polished ; hypostoma and all beneath, with gray 

 minute hair; antennae with minute gray hair, and longer sparse 

 black hair on the basal joint; occiput velvet black; wings pel- 

 lucid, stigmata and nervures brown, costal edge beyond the stig- 

 mata pale, each of the two ultimate pairs of nervures uniting 

 before they attain the edge of the wing ; poisers brown ; scapus 

 pale; pleura, pectus and coxae somewhat glaucous; feet blackish, 

 tibia and tarsi excepting at tip pale, anterior tibia at tip and tarsi 

 blackish ; tergum polished, posterior edges of the third or fourth 

 basal segments gray, spot each side of the fifth segment oblong- 

 oval oblique. 



Length three-tenths of an inch. [41 ] 



1823.] 



