THE CANADIAN ENTOMOLOGIST. 307 



name have very little real affinity with that family. On the contrary, 

 taking into consideration their larval characteristics, their narrow elongate 

 shape, and especially the shape of the head, I believe them to be genuine 

 Tenthredinids, sufficiently differentiated from the original type to form a 

 natural group by themselves, although not yet sufficiently divergent to be 

 considered a distinct family. This group may be the phylum from 

 whence originated the Selandriidje. 



The genera are very numerous, but may be recognized with the aid 

 of the following table : 



Table of Genera. - 



Lanceolate cell with a transverse or oblique nervure between the 



contraction and the apex 3. 



Lanceolate cell without such a cross-nervure, simply contracted but still 

 open before the middle. 



Hind wings with two discal cells ; front wings with four submarginal 

 cells. 



Third joint of antennas usually longer than the fourth or of an 



equal length 2. 



Third joint of antennse not longer than the fourth, usually a 

 little shorter; claws simple. 



Anal cell in hind wings much shorter than the submedian ; 

 sheaths usually triemarginate at apex . . . Thinax, Konow. 



2. Head with the frontal area well defined, enclosing the front ocellus; 



anal cell in hind wings a little shorter than the submedian, briefly 

 petiolated ; antennje slender, the first joint shorter than the 

 second ; claws with a strong tooth at bascStromboceras, Konow. 

 Head with the frontal area wanting or subobsolete ; anal cell in hind 

 wings as long as the submedian. 



Antennae shorter, thicker, less distinctly pilose, the scape short, 

 scarcely or rarely thicker than the pedicel ; third joint 

 scarcely longer than the fourth ; claws 



bifid Strongylogaster, Dahlbom. 



AntennjB long, pilose, tapering off toward tips, the scape large, 

 much thicker than the pedicel ; third joint almost as long as 

 joints 4-5 united Waldheimia, Brulle'. 



3. Front wings with three submarginal cells 12. 



Front wings with four submarginal cells. 



