RAVAGES OF CATERPILLARS. 215 



pseudo-caterpillars of one of the saw-flies (Nematus 

 Ribesii, STEPHENS). The latter insect has a flat yel- 

 low body and four pellucid wings, the two outer ones 

 marked with brown on the edge. In April it issues 

 from the pupa, which has lain under ground from the 

 preceding September. The female of the gooseberry 

 saw-fly does not, like some of the family, cut a groove 

 in the branch to deposit her eggs; c of what use, 

 then,' asks Reaumur, ' is her ovipositor saw?'* In 

 order to satisfy himself on this point, he introduced 

 a pair of the flies under a bell-glass along with a 

 branch bent from a red-currant bush, that he might 

 watch the process. The female immediately peram- 

 bulated the leaves in search of a place suited to 

 her purpose, and passing under a leaf began to lay, 



n a a, Saw-fly of the gooseberry (Nematus -Ribesii, Stephens). 6, its 

 eggs on the nervures of a leaf, d d, the caterpillars eating, c, one 

 rolled up. /, one extended. 



* See Insect Architecture, chap, vii, for a description of this 

 curious instrument. 



