HYMENOPTERA 339 



The ovipositor of the females is well developed and complicated in 

 structure. It is fitted for making incisions in the leaves or stems of 

 plants and is more or less saw-like in form. 



The larvae of the Chalastogastra are all plant-feeders. With the ex- 

 ception of those that are leaf-miners they are caterpillar-like in form. The 

 prolegs, however, are not provided with hooks as are those of caterpillars. 



A striking feature of the larvae of this suborder is the possession of a 

 pair of ocelli, one on each side, which in their position and in their struc- 

 ture agree with the ocelli of adult insects, that is, they are primary ocelli. 

 This characteristic distinguishes these larvae from the larvae of Lepidop- 

 tera. 



The members of this suborder are known as sawflies because the 

 ovipositor is saw-like and fitted for making slits in leaves and stems in 

 which to deposit the eggs. 



Family Pamphiliid^ 

 The Web-spinning and the Leaf-rolling Sawflies 



The common names given above were suggested by the fact that the 

 larvae of some species build nests by tying the leaves of their food plants 

 together with a web of silk, and others build nests by rolling the edge of 

 a leaf and live inside the tube so formed. The larvae of some species are 

 gregarious. The larvae of members of this family have long, seven- 

 jointed antennae, well-developed thoracic legs, but lack abdominal prolegs. 



The body of the adult is robust. The posterior margin of the prono- 

 tum is straight or nearly so. The mesonotum is short and never extends 

 much beyond the anterior margins of the tegulae. The anterior tibiae are 

 armed with two apical spurs. The ovipositor of the female is short. 



More than fifty species have been described from America north of 

 Mexico; but the larvae of only a few of these are known; among these 

 are the following. 



The plum web-spinning sawfly, Neurotoma inconspicua. — The larvae 

 of this species feed on the foliage of plum and cherry; they are gregarious 

 and form unsightly nests by spinning webs over the leaves; frequently 

 these webs cover an entire tree. The injury is done in early summer. 

 When full-grown the larvae find their way to the ground, where they pass 

 the remainder of the summer and winter in earthen cells; they transform 

 to pupae in the spring, and the adults emerge in May or June. 



The peach sawfly, Pamphilius persicus. — This pest of the peach is 

 one of the leaf -rolling species. The adults emerge from the ground late 

 in May or early in June and lay their eggs on the leaves; the eggs soon 

 hatch ; each larva cuts a slit in a leaf and then rolls over a portion of the 

 leaf, making a case within which it stays during the daytime, feeding 

 chiefly at night. There is a single generation a year. The larva passes 

 the winter in the ground. 



Family Siricid^e 

 The Horn-tails 



The common name horn-tails is applied to members of this family 

 because the last abdominal segment bears a more or less horn-like pro- 



