GENERAL 



25 



greater thickness of stems requires less alteration of the 

 ordinary larval form. 



i' i 



Fig. 13. A leaf-tyer of Southern California that is also a leaf-miner 

 (undetermined). A, a spray of Baccharis viminea, bearing a leaf -tie; 



B, a single leaf detached, its upper portion mined above the entrance hole; 



C, the silken bag containing the larva, removed from the center of the tie. 



The surface of a stem when it is green and covered by a 

 smooth and transparent epidermis, is not very different 

 from that of a leaf. Some observations made by one of us 



