LEAF-MINING INSECTS 



of the mine, stowed away behind a screen of white silk. 

 When grown it spins a filmy cocoon of silk, moored to the 

 walls with radiating stay lines of the same material, and 



Fig. 1. Leaf of the white aster, Aster paniculatus, with a mine of the fly 

 Phytomyza albiceps. 



Fig. 2. The white oak leaf-miner Lithocolletis hamadryadella. R, a 

 leaf of white oak bearing a ruptured mine; S f the mine enlarged showing 

 the empty chrysalis protruding; T, the adult moth. (Drawn by C. H. 

 Kennedy.) 



within this it transforms to a pupa. The pupa has a sharp 

 hornlike process on its head with which, when ready for the 

 final transformation, it can penetrate the walls. When 



