35 



The Leaf-rolling Sawfly (Blennocampa pnsilla). 

 Very frequently on wild Roses we notice a curious 

 lateral folding over of the leaves. This is due to the 

 larvae of a sawfly. During the past two years quite a 

 number of instances of this insect attack have been re- 

 ported upon cultivated Roses. In some cases to such 

 an extent that no blossom was produced. This was 

 especially noticeable in Marechal Niels. This folding 

 over of the leaves is not only disfiguring but the leaves 

 lose their proper function, and soon shrivel and die. 



If one of the folds is opened we find inside one or 

 more green larvae. This folding of the leaves is mainly 

 accomplished by the larvae, and as far as I can see it is 

 done by them when immature. Cameron, however, says 

 that they are aided by the incisions made by the females 

 when they lay their eggs. The deformity produced in 

 the leaves varies, but the rolls are always more or less 

 cylindrical. When the leaf dies the larvae move to 

 another. 



In the only cases observed personally it was noticed 

 that the attack was most severe when suckers had been 

 allowed to grow, and the attack had apparently started 

 there. At the same time I have had it reported from 

 Stockport and district, from places in Somerset and Kent, 

 where no such evils were allowed. Both Teas and hybrids 

 have been mentioned as suffering severely. 



LIFE-HISTORY AND HABITS. 



The sawfly appears in May and June ; the colour is 

 black and shiny ; the legs, black with whitish knees, 

 tibiae and tarsi ; wings dusky and irridescent. Length 



