HYMENOPTERA — SAW-FLIES, ETC. 179 



Table of Genera.^ 



Anterior wings with simple radial cell. 



Lanceolate cell widely contracted in the middle. 



Second and third cuhital cells each receiving a recurrent vein. 

 Third to fifth, sometimes sixth and seventh, antennal joints 

 of the male with a more or less prominent branch at the 

 tip ; antennae of the female somewhat compressed, and 

 with sharp projection at tip of basal joints 



Cladius, Illig. 

 Joints of antenniie without projections at tip ; third antennal 

 joint curved at the base, in the male with a short, blunt 

 fork beneath, and in the female with a sharp projection 



Trichiocampus, Htg. 

 Lanceolate cell petiolate. 



Third transverse cubital wanting . . Euura, Xewm. 



Third transverse cubital present. 



Claws bifid, clypeus usually emarginate. 



Tip of the eighth dorsal segment of the male with a small, 

 blunt, more or less awl-shaped projection ; antennae of 

 female filiform, small species 2 to 5 mm. long ; stigma 

 often having clear base ; sheath often pointed at tip ; 

 gall inhabiters . . . Pontania, Cost. 



Eighth dorsal segment of male broader, obtusely pointed, 

 or not at all produced at tip ; antennae distinctly taper- 

 ing toward tip ; stigma not lighter at base ; sheath not 

 pointed at tip ; body more robust. 



Last ventral segment of male obtusely triangularly 

 produced at tip ; sheath of female of the usual 

 form ; posterior tibiae simple. 



jNIesonotum and pleuraa shining ; antennae 

 long and slender, usually lighter coloured 

 beneath ; head, viewed from the front, 

 almost round ; labium but slightly pro- 

 jecting ; sheaths usually narrow and 

 delicate . . . Pteronus, Jur. 



1 Adapted from 'Revision of the Nematiuw of Nortli America,' bj- C. L. 

 Marlatt. Washington : 1896. In this table three or four genera are omitted, 

 as they are not, so far as hitherto recognised, associated with forest insects. 



