THE CANADIAN ENTOMOLOGIST. 205 



Table of Genera. 



Clypeus elongate, rounded or triangular anteriorly, but not dentate ; 



mandibles long Ischnogaster, Gue'rin. 



(Type I. fulgidipennis, Guer.) 

 Clypeus subemarginate or bidentate anteriorly ; mandibles oblong, 



narrowed, dentate Ischnogasteroides, Magretti. 



(Type I. flavus, Magr.) 

 Subfamily II. — Discoelinae. 

 This group was first separated by Thomson, who called it a tribe. 

 It is readily recognized by the cleft claws and by the shape of the second 

 cubital cell. 



Table of Genera. 



i . Labial palpi three-jointed 2. 



Labial palpi four-jointed 6. 



2. Petiole of abdomen swollen at the middle, and more or less contracted 



at both ends ; antennae inserted just above the clypeus 3. 



Petiole of abdomen elongate, contracted or slender only at the base ; 

 antennae inserted on the middle of the face 5. 



3. Second abdominal segment not contracted into a distinct petiole at 



base 4. 



Second abdominal segment contracted into a distinct petiole at base; 

 expansion of the petiole globularly lengthened. .Didymogastra, Perty. 



(Type D. fusca, Perty.) 



4. Second abdominal segment subsessile or very briefly 



petiolate Zethusculus, Saussure. 



(Type Zethus Jurinei, Sauss.) 



Second abdominal segment sessile or subsessile, enlarged gradually ; 



clypeus transverse, lozenge-shaped, forming a sharp lateral angle 



on each side Heros, Saussure. 



(Type Zethus gigas, Spinola.) 



5. Mandibles short, obliquely truncate Calligaster, Saussure. 



(Type C. cyanopterus, Sauss.) 



6. Petiole neither short, polished, nor campanulate 7. 



Petiole short, polished, campanulate 9. 



7. Mandibles short, stout 8. 



Mandibles rather long, obliquely truncate and 4- 



dentate Discoelius, Latreiile. 



(Type Vespa zonalis, Panz.) 



