GYMNOPTERNUS. 95 



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

 ttye 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 Gymnopternus. 



20. G. deMlis LOEW. $ and 9 Viridis, modice nitens, facie et 

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

 busque pallide flavis, alls ex flavo cinereis, lamellis hypopygii parvis, 

 pallide flavescentibus. 



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

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

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

 Long. al. 0.12. 



SYN. Gymnopternus debilis LOEW, Neue Beitr. VIII, 35, 19. 



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

 ish, front with yellow-grayish dust. Antennas 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. Tenter not. yellow. Pleura? wholly gray, without yellow 

 posterior margin. Coxae and feet pale yellowish. Tarsi towards 

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

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

 la? black. Wings only with a slight yellow-grayish tinge. Third 

 and fourth longitudinal veins towards their end almost entirely 

 parallel. The small lamellae of the hypopygium are pale-yellow- 

 ish and fringed with little black hairs. 



Hob. Pennsylvania. (Osten-Sacken.) 



Observation. G. debilis can easily be distinguished from 

 G. opacus by its smaller size and smaller antenna? ; likewise 

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

 terior margin of the pleura? not being yellow. From G. politus 

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

 &c. &c. 



21. G. crassicauda LOEW. % and 9. Viridis, modice nitens, an- 

 tennis rufis apicem versus fuscis, pi en ram m manrine postico, ventre, 

 coxis pedibusque pallide flavis, hypopygio uiaris valde iucrassato. 



