ORDER DIPTERA 



267 



The eggs are laid on the surface of the leaf and the young 

 maggots eat their way into the interior of the leaf where 

 they form their mine. The larvae are gregarious. Twenty- 

 eight larvae have been found within a single leaf of garden 

 pea. They produce small irregular blotch mines usually on 



Fig. 86. The cabbage leaf -miner, Scaptomyza adusta. 1, larva; 2, 

 mine on young cabbage leaf. 



the upper side of the leaf, close to the mid rib, mining the 

 veins as well as the leaf itself. The mine is often digitate 

 with finger like projections in which the frass is deposited. 

 Pupation takes place within the mine. The larvae may 

 mine down the petiole and transform there. There are 



