222 THE CANADIAN ENTOMOLOGIST. 



second cubital cell triangular ; ventral plate in ^ armed with a 

 spine Harpactophilus, Smith. 



4. Abdomen with the petiole never longer than the hind coxae 5. 



Abdomen with the petiole longer than the hind coxse ; mandibles 



3-dentate. 



First cubital cell receiving both recurrent nervures, or the second 

 recurrent is interstitial with the first transverse 



cubitus ; Cemonus, Jurine. 



^Diplebus, Westw. 

 First and second cubital cells each receiving a recurrent 

 nervure ; second cubital cell large, usually quad- 

 rate Pemphredon, Shuckard. 



5. Hind tibiae along the outer face spinous or subserrate 6. 



Hind tibise along the outer face smooth, unarmed. 



Head armed with a spine or tubercle between the antennae ; labrurn 



not triangularly produced Ceratophorus, Shuckard. 



Head unarmed ; labrum triangularly produced . . Passaloecus, Shuck. 



6. Head seen from in front wider than long ; clypeus at apex emarginate ; 



abdomen ovate, not longer than the head and thorax united, the 



petiole very short , Diodontus, Curtis. 



Head seen from in front elongate, longer than wide ; clypeus not 

 emarginate ; abdomen elongate, slender, cylindrical, longer than the 

 head and thorax united Polymistus, Saussure. 



North American Species. 



(i) Ammoplanus, Girard. (4) S. fulvipes, Fox, 5 . 



(i) A. columbianus, Kohl., ? . (5) S. parallelus, Say, ? . 



(2) A. constrictus, Prov. (Ana- (6) S. podagritus, Kohl, p. 



crabro), ?. (7) S. montivagus. Cam., p. 



(3) A. laevis, Prov. (Anacrabro), (4) Harpactophilus, Smith. 



p. (5) Cemonus, Jurine. 



(2) Spilomena, Shuckard. (0 C. inornatus. Say. 

 (i) S. pusilla, Say, $. (2) C. bipartior. Fox, p. 

 (2) S. Foxii, Ckll. (3) C. tenax. Fox, p ^. 



(3) Stigmus, Jurine. (6) Pemphredon, Shuckard. 

 (i) S. americanus. Pack., 9 c?- (0 P- concolor. Say, ^ <^ . 



(2) S. inordinatus, Fox, ? c? • (2) P- angularis, Fox, p ^. 



(3) S. fraternus, Say, ? (? . (3) P. nearticus, Kohl, p ^. 



