326 THE CANADIAN ENTOMOLOGIST. 



Two cubital cells, the first receiving both recurrent nervures 3. 



Three cubital cells 2. 



2. Second cubital cell receiving only one recurrent nervure 4. 



Second cubital cell receiving both recurrent nervures. 



Cubitus in hind wings originating before the transverse median 

 nervure or interstitial with it; hind tibiae usually spinous, but 

 not serrate on hind margin ; scutellum normal ; apex of 



abdomen in ,^ terminating in 2 teeth Nysson, Latreille. 



Cubitus in hind wings originating beyond the transverse median 

 nervure. 



Hind tibiae with feeble spines, never serrate ; lateral margins 

 of scutellum sometimes more or less margined, the post- 

 scutellum normal ; apex of $ abdomen terminating in 2 



teeth Brachystegus, Costa. 



Hind tibiae strongly serrated on hind margin, and also more 

 or less spinous ; lateral margins of scutellum more or less 

 strongly reflexed, the postscutellum bilobed ; apex of $ 

 abdomen terminating in 4 teeth Paranysson, Guerin. 



3. Cubitus in hind wings originating beyond the transverse median 



nervure, the latter short, straight, perpendicular ; hind tibiae on 

 outer face armed vvith 4 teeth ; pygidium very long, with the lateral 



margins denticulate Metanysson, Ashm., n. g. 



(Type N. Solani, Ckll.) 



4. Second cubital cell receiving only one recurrent nervure — the second, 



the first recurrent nervure received by the first cubital cell near its 

 apex ; posterior cox^e armed with a spine or tubercle at apex ; 



abdomen normal Helioryctes, Smith. 



(Type H. melanopyga, Smith.) 

 Second cubital cell receiving only one recurrent nervure — the first, 

 the second recurrent nervure received by the third cubital cell far 

 beyond the second transverse cubitus ; posterior coxje unarmed ; 

 hind tibiae and scutellum as in Nysson; abdomen with ventral 

 segments 4-6 each with a lateral tooth, apex of abdomen in ^ 

 3-dentate Foxia, Ashm. 



5. Second cubital cell triangular, but not petiolate, the first recurrent 



nervure received by the first cubital cell near its apex, the second 

 recurrent interstitial ; metathorax with the superior hind angles 

 produced into strong stout spines Acantho?tethus, Smith. 



