GYMNOPTERNUS. 91 



fringed on the margin with small black hairs. The interior ap- 

 pendages plain. Cox9B and feet yellowish. Middle coxa? on the 

 outside as far as somewhat beyond the middle, blackish. The 

 usual row of bristles on the upper side of the fore tibiae is com- 

 plete, and consists of comparatively large bristles. The usual 

 short hairs upon the last third of the upper side of the hind tibia? 

 are not only a little denser, but also visibly longer, than in the allied 

 species. Tarsi towards the end a little blackish. Cilia of the 

 tegulae black. Wings tinged with gray. Third and fourth longi- 

 tudinal veins towards the end a little more approximated, arid 

 therefore a little more converging, than in the allied species. 

 Hob. Middle States. (Osten-Sacken.) 



15. G. difficilis LOEW. $ . Viridis, antennis nigris, facie et fronte 

 albido-pollinosis ; pedibus flavis ; tarsis apicem versus dilute infuscatis, 

 alarum venis longitudinalibus tertia et quarta perfecte parallelis ; 

 lamellis hypopygii pallide flavescentibus. 



Green, antennae black, face and front covered with a whitish dust, feet 

 yellow, tarsi brownish only towards the tip, third and fourth longitudi- 

 nal veins perfectly parallel ; lamellae of the hypopygium pale-yellowish. 

 Long. corp. 0.12. Long. .al. 0.12. 



SYN. Gymnopternus difficilis LOEW, Neue Beitr. VIII, 33, 14. 



Is so extremely like the preceding species, that the statement of 

 the differences will be sufficient for its recognition. They consist 

 in the following : the usual row of bristles on the upper side of 

 the fore tibias consists of much smaller bristles. The hairs on the 

 upper side of the hind tibiae are, towards their end, less dense and 

 long ; the third and fourth longitudinal veins are perfectly parallel 

 towards their end, and all the longitudinal veins have a paler 

 coloring. 



Hab. New York. 



16. G. nigritoarbus LOEW. $ . Nigro-seneus, thorace cserulescente, 

 subopaco, inferS, faciei parte pilis nigris barbata. 



Bronze-black, thorax rather blue and somewhat dull, the lower part of the 

 face bearded with black hairs. Long. corp. 0.09 0.10. Long. al. 0.12. 



SYN. Gymnopternus nigribarbus LOEW, Neue Beitr. VIII,. 33, 15. 



Bronze-blackish, thorax rather blue, and rather dull on account 

 of a dense, brown-gray dust. Face covered with a whitish-gray 

 dust, rather broad, upon its inferior portion convex and beset with 



