130 ON THE CATERPILLARS 



long jaws, in both which respects it differs from the pupa 

 of the moth, although the cocoon is almost identical both in 

 form and texture with the cocoons of those moths which are 

 called Eggers. The jaws are of the greatest use to the enclosed 

 insect, as it is by their aid that it is enabled to make its 

 escape out of its cocoon ; the moths, it is true, are enabled, 

 without such jaws, to effect their escape, by emitting a 

 peculiar fluid which softens the threads of the cocoon, and 

 thus allows their escape; but the saw-fly is provided with 

 no such fluid, and is obliged to pierce the cocoon near one 

 of its ends with the point of one of its jaws, after which it 

 works them conjointly like a pair of scissors, and so cuts off 

 a small circular cap at the end of the cocoon, and thus effects 

 its escape, which it does immediately after assuming the 

 winged state, the wings extending to their full size on 

 the insect gaining its liberty. It now resembles a large, 

 rather long, hairy, brown bee, with the abdominal part 

 of the body soldered to the thorax. 



The leaves of the raspberry plant are often covered with 

 large blotches in July, which are caused by the fleshy portion 

 of the leaf being eaten away, leaving the two surfaces entire; 

 within these blotches will be found one, or, occasionally, two, 

 or even three, small dirty greenish caterpillars, haying three 

 pairs of jointed legs, six pairs of ventral and a pair of anal 

 prolegs ; the segment next the head is dark brown in front, 

 the head itself fulvous, the 2nd, 3rd and 4th segments having 

 a black dot on the underside, and the anal prolegs surrounded 

 at the base with a black ring. These caterpillars shed their 

 skins several times, leaving the exuviae within the blotch ; 

 when full grown they eat their way out of the blotch, which by 

 that time nearly occupies the entire leaf, and then descend to 

 the earth, where they make their cocoons, the perfect insect 

 appearing at the beginning of August, in the shape of one 



