NORTH AMERICAN HYMENOPTERA. 59 



Synopsis of* the ^^ortlt Aiiiericaii Siib-raiuilies and 

 Genera of CYXIPID^E. 



BY WILLIAM H. ASHMEAD. 



Family— CYNIPIDJE. 



Head generally (<niall, transverse ; labruni very minute ; mandi- 

 bles short, robust, toothed ; maxillary palpi -Vjointed, labial palpi 2 

 to 4-)ointed ; antennae slender, filiform, or sub-filiform, inserted on 

 the middle of face, 12 to 16-jointed ; thorax generally thick, oval; 

 scutellum large, variable ; wings with few nervures, anterior pair with 

 seldom more than three or four cells, posterior pair with but a single 

 thickened vein, occasionally apterous ; abdomen petiolate or sub-ses- 

 sile, oval, elongate Qval or compressed, and usually with the second 

 or third segment the largest ; ovipositor spiral, hidden within two 

 sheaths or plates ; legs ordinary. 



Classificaiion of ihe North Americroi Species. 



Authors are by no means agreed in their arrangement of the com- 

 plexity of forms recognized as Cynips, and in the present essay will be 

 found a new classification, in accordance with what seems to me the 

 most natural method and for which I am alone responsible. 



The forms peculiar to our fauna seem naturally to divide into two 

 sections, distinguishable from each other by venation and ventral 

 charactei's as follows : 



Section I, Gymxogastri. — Venter visible, or visible for moi'e than 

 half its length ; radial area long and narrow. 



Section II, C-ryptogastri. — Venter not visible, or with the tip 

 alone occasionally exposed ; radial area an equilateral triangle. 



The first section includes the true gall makers or Psenides, the guest 

 flies or Inqul/ines, and the peculiar genus Ihalia. 



Their habits as far as known are phytophagous, although the 

 Ibalite are supposed to be parasitic on wood-boring larvae, and by 

 some authors are placed with the Figltides. Their characters, how- 

 ever, place them naturally with the phytophagic Cynipidse. 



In the second section are included all the parasitic Cynips or Figi- 

 f!flp.<< : all are strictly entomophagous. 



