FC ORES — NYSSONIDiK 117 



2.— "Second submarginal cell receiving the first recurrent iiervure at al)out the 

 rniddle, and the second between the middle and apex ; first discoi- 

 dal cell very long and narrow, much longer than the first submar- 

 ginal cell ; submedian cell of posterior wings oblique or sinuate at 

 tip. 

 Submedian cell of posterior wings as long or nearly as long as the median 

 cell on the externo-medial nervure; face generally broad, not nar- 

 rowed towards the clypeus, which is transverse; antennte inserted 



near the base of the clypeus Gorytes Latr. 



Submedian cell of posterior wings longer than the median cell on the 

 externo-medial nervure ; face narrowed towards the dyjicns, which 

 is generally subtriangular ; antennee inserted higher up above the 



clyi>eus HopliHUMSt. Farg. 



Second submarginal cell broad, receiving the second recurrent nervure very 

 near the tip, the first recurrent nervure uniting with the first trans- 

 verse cubital nervure ; first discoidal cell diamond shaped, broad in 

 the middle and not longer than the first submarginal cell on the 

 dividing nervure ; submedian cell of posterior wings much shorter 

 than median cell on the externo-medial nervure, truncate at tip ; 



abdomen siibpetiolate, first segment nodose EuMpongns St. Farg. 



3. — Abdomen subsessile ; prothorax subquadrate, narrower than the mesothorax ; 

 posterior femora with a stout tooth near the tip ; apical joint of % 



antenna? crescent-shaped Alyson Jur. 



Abdomen sessile ; prothorax transverse, as broad as the mesothorax. 

 Three submarginal cells. 



Posterior tibia; serrate; lateral margin of scutellums strongly reflexed, 

 postscutellum bilobed ; apex of % abdomen generally with four 



teeth Paranysson Guer. 



Posterior tibiae not serrate ; lateral margin of scutellums not reflexed, 

 , postscutellum narrow, not bilobed ; apex of % abdomen with not 



more than two teeth Mysson Latr. 



Two submarginal cells Hypoiiysson Cress. 



The genera Gorytes and Hoplkus are closely allied, differing prin- 

 cipally in the neuration of the posterior wings ; of the twenty-five 

 species which have been described under the former genus, fourteen 

 are known to belong to Hoplisiis. 



Exu<pongm, a very <listinct genus, is represented by a single species, 

 bipuiidatiis Say, a siiiiill insect of unconnnon occurrence. 



The genus Alyson, characterized by the subquadrate prothorax, 

 petiolate second submarginal cell and toothed posterior femora, con- 

 tains three species, generally rare in collections. 



Of the remaining genera, Paranysson, which has two species from 

 Texas and the far Western States, differs chiefly by the serrate pos- 

 terior tibiae and form of the scutellum ; while Hyponysson, which 

 closely resembles Nysson, differing only by having two submarginal 

 cells instead of three, is represented by a single species of small size 



