HYMEN OP 'TEKA. 



611 



is composed of two segments (Fig. 737, b), while in the 

 Stinging Hymenoptera it consists of a single segment. 

 There may be exceptions to this characterization among the 

 minute members of the Terebrantia ; but the beginning 

 student will hardly undertake the study of these. 



Family TENTHREDINID,E (Ten-thre-din'i-dae;. 



The Saw-flies. 



In this family the head and thorax are wide ; the base 

 of the abdomen is not slender, as in most Hymenoptera, but 

 broadly joined to the thorax (Fig. 743, j) ; and the abdomen 



Fig. 743. — The Locust saw-fly, Nemattis similaris : <z, egg ; 3, young larva ; c, full- 

 grown larva ; d, anal segment of full-grown larva ; e, cocoon ; _/", adult. (From the 

 Author's Report for 1879.) 



of the female is furnished with a pair of saws. The larvae 

 look like caterpillars and feed upon leaves (Fig. 743) ; but 

 they have, ordinarily, from twelve to sixteen prolegs, while 



