GYMNOFTERXUS. 95 



Observation. — It is remarkable that the circle of short thorns on 

 the tip of the abdomen of the female, which belongs to allied spe- 

 cies, is wanting- here. This species, however, cannot be located 

 in any other genus; on the contrary, it coincides most perfectly 

 in all other respects with the species of Gymnoptemus. 



20. ii. rietoilis Loew. % and 9. — Viridis, modice nitens, facie et 

 fronte cinereo-pollinosis, antennis rufis apicem versus nigris, coxis pedi- 

 busque pallide flavis, alis ex fiavo cinereis, lainellis hypopygii parvis, 

 pallide flavescentibus. 



Green, moderately shining ; face and front grayish-dusty, the red antenna? 

 black at the tip ; coxse and feet pale-yellow ; wings yellowish-gray ; the 

 small lamellae of the hypopygiuni pale-yellowish. Long. corp. 0.12. 

 Long. al. 0.12. 



Syn. Gymnoptemus debilis Loew, Neue Beitr. VIII, 35, 19. 



Green, only moderately shining ; face covered with white-gray- 

 ish, front with yellow-grayish dust. Antennae red, of middle size : 

 third joint quite distinctly hairy, at the tip black-brown and pro- 

 vided with a sharp angle ; arista with a short, but distinct pubes- 

 cence. As far as I can perceive, the cilia? of the inferior orbit 

 are black. The upper side of the thorax, on account of some 

 yellow-grayish dust, rather dull. The scutellum seems to be 

 bare. Venter not. yellow. Pleurae wholly gray, without yellow 

 posterior margin. Coxa? and feet pale yellowish. Tarsi towards 

 their end a little nifuscated. The usual row of bristles on the 

 upper side of th*> fore tibiae rather prominent. Cilia of the tegu- 

 lae black. "Wings only with a slight yellow-grayish tinge. Third 

 and fourth longitudinal veins towards their end almost entirely 

 parallel. The small lamella? of the hypopygiuni are pale-yellow- 

 ish and fringed with little black hairs.- 



Hab. Pennsylvania. (Osten-Sacken.) 



Observation. — G. debilis can easily be distinguished from 

 G. opacus by its smaller size and smaller antennas; likewise 

 from G. erassicauda by not having a yellow venter and the pos- 

 terior margin of the pleurae not being yellow. Prom G. politus 

 it differs by a more light-green color, less brightness, smaller size, 

 &c. &c. 



21. ii. crassicamla Loew. % and 9.— Viridis, modice nitens. an- 

 tennis rulis apicem versus fuscis, pleurarum margine postico, ventre. 

 coxis pedibusque pallide flavis, bypopygio man's valde inorassato. 



