20Q HYMENOPTERA. 



wings have a very short, bent costal (radial) vein. C. arma- 

 tum Say was described from Indiana. 



The egg-parasite, Teleas, has the elbowed twelve-jointed an- 

 tennae inserted very near the front of the head, and slightly 

 hairy and simple in the male, but in the female terminated in a 

 six-jointed club. The thorax is short, the legs thickened and 

 adapted for leaping, and the abdomen is pedicelled. Many 

 species have l)een found in Europe. According to Westwood, 

 ''the type of this genus is the Ichneumon ovulorum of Linnaeus 

 (Teleas Linnoii Esenbeck), Avhich Linnaeus and 

 De Geer obtained from the eggs of moths." It 

 has been raised from the eggs of several Bom- 

 bi/cidce. " Bouche observed the female deposit 

 Fig. 134. Jill Qgg in each of the eggs of a brood of Bom- 

 byx neustria. He describes the larva as elliptical, white, 

 shining, rugose, subincurved, and one-third of an inch long." 

 (Westwood.) 



Of the extensive genus Platygaster over a hundred European 

 species are already known. The body, especially the abdomen, 

 is generally flattened, the antenna? are ten-jointed, and in the 

 female clavate. The wing A-eins are absent ; the rather slender 

 legs arc not adapted for leaping, and the tarsi are flve-jointed. 

 A species of Platygaster (Fig. 134) not yet named, oviposits 

 in the eggs of the Canker-worm moth, Anisopteryx vernata, 

 and by its numbers does much to check the increase of this 

 caterpillar. We have seen several of these minute insects 

 engaged in inserting their eggs into those of the Canker- 

 worm. 



Dr. Harris, in spealdng of the enemies of the IIessian-fl3-, 

 states, that "two more parasites, which Mr. Herrick has not 

 yet described, also destroy the Hessian-fly, while the latter is 

 in the flax-seed or pupa state. Mr. Herrick says, that the egg- 

 parasite of the Hessian-fly is a species of Platygaster, that it is 

 very abundant in the autumn, when it lays its own eggs, four 

 or five together, in a single egg of the Hessian-fly. This, it 

 appears, does not prevent the latter from hatching, but the 

 maggot of the Hessian-fly is unable to go through its trans- 

 formations, and dies after taking on the flax-seed form. Mean- 

 while its intestine foes are hatched, come to their growth, spin 



