HYMENOPTERA. 



17 



wounds being subsequently closed with a viscid secretion which protects the eggs. 

 As many as twenty eggs may thus be deposited in a single needle. When young, 

 and also just before turning into pupa?, the grubs are very susceptible to sudden 



FEMALE AND MALE OF GIANT-TAILED WASP (nat. size). 



cold or heavy rain, which will kill off thousands. In addition to these destructive 

 agencies, nearly forty different kinds of parasites infest the grubs, while mice 

 devour numbers of the pupae. The illustration below shows all the stages of de- 



1, pine saw-fly, larvae on pine needles, and also pupse cases shut and open ; 2, broad-bodied saw-fly, 



with larvae and nest. (All nat. size. ) 



velopment, one of the grubs being drawn in the act of endeavouring to ward off the 

 attacks of a parasite by the ejection from its mouth of an offensive fluid. To the 

 same family belongs the turnip saw-fly (Athalia spinarum), which is one of the 

 vol. vi. — 2 



