HYMENOPTERA (SAWFLIES). 



189 



a small glossy black insect, about one-fourtb of an inch in 

 length ; the wings are iridescent, with the middle area smoky 



Fic. 91. — Sltjg-worm of Pear (Eriocampa li-macina). 



black, and are about three-quarters of an inch from tip to tip. 

 The parent fly comes out of the ground beneath the trees in the 

 spring, generally in May. In most cases a single egg only is 

 placed on the under-side of each 

 leaf, its position being easily told 

 by the small pale spot that appears 

 over it. The ovum hatches in two 

 weeks, and the larva escapes to 

 the top of the leaf. At first it is 

 pale and free from slime ; but soon 

 a slimy exudate comes out of its 

 skin and gives it its typical slug- 

 like appearance. Its form is 

 peculiar, being much swollen up 

 at the head-end : it has twenty 

 legs. In four weeks the slug- 

 worm has reached maturity, when 

 it attains the length of half an 

 inch. At the last moult (the 

 fifth) it loses its slimy character, 

 and becomes dry and dirty-yellow 



in colour. It then falls to the ground, where it forms a cell 

 and pupates. In the summer broods, of which there are three 

 in England, the pupal life lasts about fourteen days. It seems 



I. — Pear Sawfly (Erwcavipa 

 limiiciTui)^ finfl cocoon. 



