COLLECTING AND PRESERVING INSECTS HANKS. 



33 



female abdomen shows an ovipositor with pieces having a sawlike 

 edge. The larvae have three pairs of true legs, and often numerous 

 prolegs. They feed on plants, and some species make galls on willow. 

 There are two families, Tenthredinidae and Uroceridae. 



The Parasitica , which includes an enormous series of species, the larvae 

 of which live in caterpillars or 

 otherinsects (seefig. 139). They 

 are therefore very beneficial. 

 These have the abdomen slender 

 at base, forming a pedicel, the 

 first segment connected to the 

 thorax. The trochanters are 

 usually of two pieces. Many 

 are slender insects with fairly 

 long legs, and among them are 

 many minute forms, some so 

 small that one may be crawling 

 across this page unseen by the 

 reader. 



The Proctotrypidae are the 

 tiniest of these forms : the young FlG - C "-~ A sawmy, eeiocampoides umacina: a, fly; 



..... i> 1 6, f, CATERPILLAR OR SLUG; (?, EATEN LEAVES. 



usually live m the eggs or other 



insects. The Chalcididae (figs. 66, 67 ) are very numerous, and of variable 

 habits; some live in the seeds of various plants, the joint worms in the 

 stems of grasses, but most are parasitic on other insects. In some 

 cases, although the parent lays but one egg in a caterpillar, several 

 hundred flies may develop from it. The Ichneumonidae (fig. 68) and 



Braconidae (fig. 69) 

 are closely related, 

 and include the 

 largest species. All 

 are parasitic on 

 otherinsects; many 

 are prettily colored. 

 The females of 

 many species have 

 long, p rominent 

 ovipositors, some- 

 t imes much longer 

 than the body. 

 Sometimes one of 

 these parasites has 

 a parasite upon it, the latter being called a "liyperparasite." 



The Cynipidae, or gallflies (fig. 70), are small insects, many making 

 galls upon the leaves and twigs of plants, the larva- living and devel- 

 oping therein. 



The Heterogyna, or ants (Formicidae) , include a number of well- 

 known insects whose industry and intelligence have excited the 



Fig. 66. — A Chalcis-fly, EuPELMtrs llmnerle. 



