52 ACADEMY OF NATURAL SCIENCES 



giderable rapidity, constantly advancing its long anterior feet 

 Its bite is pungent. 



BEKIS Latr. Meig. 



B. FUSCiTARSis. — Thorax piceous-black, polisbed; tergum 

 reddish-brown, inclining to yellowish on the disk, and with brown 

 incisures. 



Inhabits Pennsylvania. 



Wing hyaline with a pale-brown stigma and nervures, origin 

 yellowish-white; thorax with the posterior angles piceous; feet, 

 anterior and intermediate pairs yellowish-white ; tarsi, excepting 

 the base of the first joint, fuscous, posterior pair reddish-brown, 

 first joint of the tarsi yellowish-white. 



Length one-fifth of an inch. 



The scutel of my specimen i« wanting ; I sannot, therefore; 

 ascertain its number of spines, 



NEMOLETUS Geofl^. Latr. Meig. 



N. PALLIPES,— Greenish-blaek, thorax tinged with green; ner- 

 Tures ^hitish. [30] 



Inhabits Pennsylvania. 



Rostelliform process blued-black, polished ; antennae brown, 

 situate at the base of the rostelliform process ; front with a tri- 

 angular white spot above the antennae ; thorax punctured, a tes- 

 taceous line before the wings, and another each side on the basal 

 edge; poisers and scale pure yellow-white; costal nervures 

 whitish ; feet yellowish, base of the thighs and middle of the pos- 

 terior edges of the segments of the venter rufous. 



Length thres-twentieths of an inch, % . 



XYLOPHAGUS Meig. 



X. TRIANGULARIS. — Black, sub-glabrous ; thorax plumbeotrs 

 with a black line ; feet testaceous. 



Inhabits Missouri. 



Body black ; head pale plumbeous ; antennas and paJpi black ; 

 proboscis pale rufous ; trunk black polished ; thorax, disk pale 

 plumbeous, with a longitudinal polished black line, gradually 

 and slightly dilating behind ; nervures fuscous ; halteres white • 

 feet testaceous, tips of the tarsi and of the posterior thighs and 



[Vol. III. 



