154 THE CANADIAN ENTOMUlAAUbT. 



Labrum neither large, /ree, nor distinct, usually entirely hidden under the 

 clypeus, or at most with only a part — the tip — exposed ; anterior tarsi 

 in 9 most frequently 7ejii/i a comb ; hind tibice in ? frequently serrate 

 and spinous, or only spinous, more rarely smooth, witJwiit spines, except 

 in males. 



Second ventral segment always luithout a transverse grooved line, 

 impression or emargination ; hind tibi» in $ 7iever serrate, although 



usually spined in both sexes ; stigma rarely well developed 2. 



Second ventral segment in $ with a distinct transverse grooved line, 

 impression or emargination ; stigma well developed. 



Hind tibiae in % most frequently strongly serrate and also spinous, 

 rarely without teeth or indistinctly serrate, in the latter case 

 with a strong longitudinal ridge ; in $ simple, neither serrate 

 nor spinous, the hind tarsi very long, often more or less 

 flattened or compressed, the basal joint long and often bent 

 or more or less curved ; second ventral segment with 

 a transverse grooved line or emargination in both 



sexes Subfamily I., Pepsinte. 



Hind tibise in both sexes smooth, without teeth or spines, at the 

 most with very minute, scarcely perceptible or feeble spines, 

 never with a distinct longitudinal ridge ; second ventral 

 segment with the transverse grooved line present in 5 only, 



absent \\\ $ Subfamily H., Ageniinas. 



2. Hind tibiae in both sexes smooth, without spines, or at most with very 



mifiute, scarcely perceptible or feeble spines 3. 



Hind tibi?e in both sexes always strongly or distinctly spined, the spines 

 always well developed. 



Antennae inserted on the anterior margin of the head on or belozv 

 an imaginary line drawn from the base of the eyes ; head antero- 

 posteriorly very thin, the face, clypeus and temples in $ very 



flat 4. 



Antenna inserted far above such a line, or on or near the middle 

 of the face, or at least considerably above the basal suture of 

 the clypeus ; head normal, or nearly ; front wings with two or 

 three cubital cells. 



Clypeus anteriorly not produced, truncate or emarginate, 

 not wholly covering the mandibles ; pronotum rarely 

 long •» . .Subfamily HI., Pompilinte. 



