plotcs 0it t|)c Jabits of il^t ^arba of 

 6racillarra Sjimrgtlla* 



By H. J. CHARBONNIER. 



Read at the General Meeting^ October bfh, 1892. 



IF we examine the lilac trees in our gardens in spring, 

 May or June, we shall notice that some of the leaves are 

 disfigured b}^ being mined in large brown blotches. If we 

 open one of these " blotches," we shall find it to be the home 

 of from four to twelve nearly transparent, greenish white 

 larvse, actively engaged in eating the parenchyma of the 

 leaf, the upper and lower cuticles of which act as floor and 

 ceiling of their temporary dwelling. 



As soon as the space between the two cuticles becomes 

 too shallow for the growing larvae, they change their 

 method of working, and, passing out on the under side of 

 the leaf, proceed to roll it upon itself, with the help of 

 numerous silken threads, almost invariably beginning at the 

 tip of the leaf, secure in this retreat. Feeding uj)on the 

 under surface of the leaf, they take care in rolling it to 

 preserve the form of a loose scroll, so that by continuing 

 the rolling they constantly enlarge their habitation. 



As the larvae advance from the tip of the leaf, the in- 

 creasing size and stiffness of the midrib become serious 

 obstacles, to obviate which, the larvse carefully cut notches, 

 nearly, and sometimes quite, through the midrib. These 

 notches are generally at fairly regular distances, nearer 

 together at first, and becoming more distant as the size 



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