THE HOLLY LEAF-MIXER. 41 



THE HOLLY LEAF-MINER. 



Chromatomyia ilicis, Curtis. 



In Sutton Park, and generally throughout the Midlands, the 

 Holly Leaf-Miner abounds, and so numerous has it become tha' 

 it is now quite the exception to find certain varieties of holly free 

 from this pest. 



FIG. XXII. LE.AVKS OF MARGUERITE ATTACKED BY Fi Y. 



LIFE-HISTORY. 



The life-history of this fly was first worked through in 

 1902-3, and again in 1903-4, when it was present in my own garden 

 in small numbers. 



Early in June the female fly deposits her eggs on the under 

 side of the leaves ; so far as my observations go, only a single egg 

 is placed on each leaf, and on the mid-rib close to the leaf-stalk. 

 In seven or eight days the larva hatches out and makes its way 

 into the vessels of the mid-rib, and then commences to slowly 

 travel forwards. In September, October, or November it leaves 

 the vessels, and tunnels its way into the soft, green tissue of the 

 leaf, forming galleries which give the leaf a blistered appearance. 



By the following April the larva is mature, and it now bites 

 through the epidermis in order to provide an exit for the fly. Like 

 many other flies, it retains its last larval skin as a protection for 

 the thin, white pupal case. The pupa is of a flattened oval form 

 and marked by a number of regular transverse segments, the 

 original segments of the larval skin; within this is a second skin, 

 which is the true puparium. 



