250 long's second expedition. 



Inhabits North-west Territory. 



Antennae fuscous, with dark gray hairs ; wings a little dusky 

 nervures fuscous; poisers elongated, whitish, capitulum fuscous; 

 abdomen fuscous, opaque. 



^ Length of the body one-twentieth of an inch. 



V A little larger, with the base of the feet and of the poisers of 

 a darker shade than those of the male. 



SCATOPSE. 



S. atrata. — Deep velvet black; tarsi pale; tip of the an- 

 tennas abruptly compressed. 



Inhabits Pennsplvania. 



Body hardly polished and nearly opaque, immaculate ; poisers 

 color of the body ; Avings hyaline ; marginal nervures but little 

 more than half the length of the wing, fuscous ; furcate nervure 

 attaining the tip ; below the furcate nervure are two parallel ner- 

 vures which do not reach the margin ; beneath the latter is the 

 ordinary undulated nervure. 



I obtained several specimens which were crawling on the glass 

 <:' a window, in September, in Philadelphia. The [368] ner- 

 vures of the wings differ somewhat from those of the S. notata, 

 Linn. Meig. ; the marginal nervures do not approach so near the 

 tip of the wing, and instead of a single nervure between the forked 

 nervure and the undulated nervure, as in the notata, this species 

 lias two. 



BIBIO Latr. Meig. 



B. thoracica. — Black; thighs rufous. 



Inhabits East Florida. 



Body black, somewhat polished ; thorax bright yellowish-ru- 

 fous, with a small black spot on each side of the scutel ; collar, 

 seutel, and metathorax black ; spines of the anterior tibiae pice- 

 ous, the exterior one much larger ; wings fuscous ; the fourth 

 marginal nervure abbreviated, and not attaining to the inner mar- 

 gin. 



Length 9 two-fifths of an inch. 



This is a very large and fine species. On the thorax is some- 

 times an obsolete brown line. 



