64 ACADEMY OP NATURAL SCIENCES 



short spine on the superior surface rather beyond the middle, and 

 a small oblong-ovate denuded space on the inner surface. The 

 wing nerNTires arc arranged as in Dioctria and Dasypogon. 



Genus DASYPOaON Meig. 



1. D. 6-FASCiATUS. — Cinereous; abdomen black, with a white 

 band on each segment. 



Inhabits iMissouri. 



Body black, densely covered with short cinereous hair ; head 

 with longer silvery hair ; antennas black ; nervures fuscous ; ter- 

 gum black, polished, each segment with a white band at tip, a 

 little dilated in the middle, and occupying about one-third of its 

 proper segment ; thighs and tibia testaceous at base ; halteres pale. 



Length seven twentieths of an inch. 



[The genus Dasypogen formed of the most heterogeneous ele- 

 ments, has been subdivided by Prof. Loew, into seventeen groups 

 or subgenera, comprising the European species only. The Amer- 

 ican species for the most part belong to new groups, as yet unde- 

 fined. Those of Say's species which I know to belong to one of 

 Loew's groups, I refer to them, leaving the others in the genus 

 Dasypogon in Meigen's acceptation. — Sacken.] 



2. D. ABDOMiNALis. — Yellow ; thorax cinereous ; wings dusky. 

 Inhabits Pennsylvania. 



Body cinereous; head with an impressed line between the an- 

 tennae ; antenna; and rostrum black ; thorax with an abbreviated, 

 brown line before and a lateral interrupted one ; wings dark brown 

 immaculate ; abdomen bright-yellow, very slightly tinged with ru- 

 fous, immaculate ; feet pale rufous, tibia [51] dusky at tip, tip of 

 the posterior ones dilated, and first joint of the posterior tarsi also 

 dilated and as long as the three following segments united. 



Length less than three-tenths of an inch. 



The head is very wide, the eyes being proportionally very large, 

 the vertex deeply concave, and the stemmata placed on a common 

 elevation. 



[This is a D iscocrphala Macq. Synonymous with D. rujlven- 

 trig Macq. — Sacken.] 



3. D. trifasciatus. — Cinereous; tergura black, trifasciate 

 with whitish. 



Inhabits Pennsylvania and Maryland. 



[Vol. in. 



