The Proctotrypoid Parasites 



parasitic Hymenoptera. In the Proctotrypoidea a curious hyper- 

 metamorphosis occurs in certain egg parasites in which there are 

 three distinct forms of the larva of the same species, one form 

 resembling the little aquatic animals of the genus Cyclops. 



The eggs of the Proctotrypoids are ovate, with a peduncle 

 at the end. Nearly all of the larvae live within other insects. 

 Very many of them live in insect eggs, undergoing their trans- 

 formations within these eggs, sometimes a half-dozen or more 

 being found within a single egg-shell. Still others live within 

 the larvae or the pupae of insects, in which case they gnaw their 

 way out before spinning cocoons, or sometimes transform within 

 the body of the host, in which case there is usually no cocoon, 

 the skin of the host giving ample protection. The insects of 

 one genus, Trichacis, develop in the nervous system of the larvse 

 of one of the little gall midges, while the larvae of another genus, 

 Polygnotus, develop in the diges- 

 tive tract of the same insect. 



As just stated, many of them 

 develop in the eggs of other in- 

 sects, such as butterflies, moths and 

 true bugs, as well as grasshoppers. 

 Many times students interested in 

 rearing butterflies from the egg will 

 be disappointed, instead of hatching 

 out caterpillars to find numbers of 

 the extremely minute black four- 

 winged flies of the Proctotrypoid 

 genus Telenomus, which make their 

 appearance through minute perfora- 

 tions in the egg-shell. The eggs 



Fig. 26. Baeus americanus. 

 (Author's illustration.) 



of the mourning-cloak butterfly (Eu-vanessa antiopa) are espe- 

 cially apt to suffer in this way. 



Other Proctotrypoids live in the larvae of gall-flies, gall-gnats, 

 of many kinds of flies, of butterflies and moths and beetles, and 

 in plant-lice, and the eggs of spiders, as well as of bugs, butter- 

 flies and moths. Some of the species (of the genus Bceus) which 

 live in spider eggs are very curious, wingless creatures of 

 simple form. 



The curious family Pelecinidae is placed in this super-family 

 by Ashmead, and it forms an exception to the remainder of the 



5 1 



