HYMENOPTERA : ICHNEUMONID^E. 375 



feed upon the larvae of those upon whom they have in- 

 truded. 



PROCTOTRUPID^E, Latr. This Family comprises a vast 

 number of minute hymenoptera with rather long, slender 

 bodies, wings without nervures, and covered with minute 

 hairs, and the antennae often haired on the joints. Scarce- 

 ly any of these insects exceed a quarter of an inch, and 

 most are very minute, hardly distinguishable by the un- 

 trained eye. They are generally black, varied with brown. 

 They prey upon other small insects by ovipositing in their 

 eggs or in their larvae. 



The Genus Platygaster contains a species which lays 

 its egg in those of the canker-worm moth. It is only one 

 twenty-fifth of an inch long. 



CHALCIDID.E, Spinola, OR CHALCIS FAMILY. This 

 Family also comprises a great number of parasitic hymen- 

 optera of small size, but of brilliant colors. Their anten- 

 nas are geniculate, and wings often deficient in nervures. 

 Some species prey upon plant-lice, others lay their eggs 

 in the nests of bees and wasps, and others consume the 

 larvae of the Hessian Fly, and of those insects which pro- 

 duce galls. Some species are parasites on other para- 

 sites ; as, for instance, Aphidius of the next family, which 

 is parasite on the plant-lice, has itself parasites which are 

 members of this family. 



ICHNEUMONID.E, Latr., OR ICHNEUMON FAMILY. This 

 Family, the most extensive in numbers of the hymen- 

 optera, comprises insects with the body long and narrow, 

 the antennae long, ovipositor generally long, Fig 

 and protected by two threads or sheath- 

 pieces of the same length, and the anterior 

 pair of wings always exhibiting perfect 

 cells upon their disk. The color is gen- 

 erally black, varied with red, yellow, or 



. . . , , ,, , Ichneumon, /. sur- 



white. They attack almost all other in- turatis, Say. 



