Insects, etc., Injurious to the Pear. 341 



are three pairs of yellow claw-like legs. Tlieie arc no prologs at 

 all, but on the anal segment are two long backwardly projecting 

 spines, looking like antennae. The antenna3 are long. A dark green 

 line shows down the middle of the body, caused by the alimentary 

 canal containing the green leaf substance upon which the larvtc 

 have been feeding. 



Having no prolegs they walk with difficulty when once they have 

 left their web, wriggling much like a worm and progressing backwards 

 with violence if touched, much after the manner of the caterpillar 

 of Ihe Garden Swift {Hepialm Inpulinm). They exude a drop of clear 

 deep coffee-coloured fluid from the mouth and from behind the 

 head and other parts when frightened. This fluid is sometimes 

 quite red and clear, looking like blood. Tliey will expel this when 

 an Ichneumon settles upon them. Its function is evidently to 

 frighten off such enemies. AMien in the webbing they wander 

 about with much ease, usually collecting together in a group vrhen 

 not feeding. The larva;', 

 never seem to actually 

 leave the nest, but 

 when feeding they 

 partly expose their 

 bodies outside the tent 



and devour the leaves ' [/-•. Edemien.. 



all round. They com- fig. ■h^.-i^av.xje of social peau sawfly. 



mence by devouring the 



edges of the leaves and work down to the mid rib, which they 

 generally seem to leave intact. When the leaves around the nest 

 are all cleared they form another tent near the last and commence 

 afresh. As many as six nests may be found on one pear tree, 

 evidently all formed by the same colony. 



There is considerable variation in the time of appearance, for in 

 the same tree fully matured and half' grown larvre may occur. The 

 first date of pupation observed was the l7th of July, but by August 

 many larva? were still alive in 1890. Eoughly speaking, the larvte 

 take five weeks to mature. They then attain the length of 1 inch. 

 When ready to pupate they lower themselves to the ground by a 

 thread of silk, and at once commence to burrow into the earth to a 

 depth of 3 to 5 inches, where they spin a thin cocoon in which they 

 remain all the winter, and in which they pupate in the spring. 

 Miss Ormerod (1) says they do not form a cocoon, but make a smooth 

 cell in the earth ; this is contrary to other observations (2). 



The pupffi seem to be able to suspend development, and may live 



