THE LILAC LEAF-MINER. 37 



The observations and experiments were made on nine trees 

 about five feet in height and growing five or six feet apart. 



The moths of the first brood were noted on May 24th, rather 

 later than in 1904. The eggs were noticed on both the upper and 

 under surfaces of the leaves a few days later, 2/th and 28th, and 

 the caterpillars hatched out on June 4th. They at once made their 

 ^vay into the leaves, and commenced to feed upon the soft parenchy- 

 inatous tissue between the upper and lower epidermis. The largest 

 numbsT found in any one leaf was thirteen. Sometimes the whole 



FIG. XX - LEAVES OF LILAC ATTACKED BY LEAF-MINER. 



oi one side of the leaf was tunnelled; in other cases the basal half 

 was blistered before the apical ; whilst in others the blisters were 

 irregular and scattered over the leaf. 



The young larvae are almost transparent and glossy; a little 

 later they have a faint yellowish tinge, with a narrow median green 

 line caused by the green chlorophyll in the intestine. After feeding in 

 the leaf for about three weeks, they creep out on to the surface and 

 commence to feed on the epidermis, the leaves rolling up laterally 

 or from the apex. About ten days later they become full-fed, and 

 are slightly over a quarter of an inch in length, with a prominent 

 brown head. Here they remain for about ten days, then leaving the 

 rolled leaves and pupating in the axils of the leaves or branches, 



