246 



LEAF-MINING INSECTS 



had been burned by spray material or by the sun. The 

 mature larvae frequently transform within the mine, al- 

 though they may escape and attach themselves to the sur- 

 face of the leaf or hide away in a curled part of it. 



AGROMYZIDAE 



This is a family of small flies, the habits of many of which 

 are still unknown. The larvae seem to be largely plant 



Fig. 75. The parsnip leaf -miner, Acidia heraclei. a, adult; 6, larva; 

 c, /, h, details of larva; d, puparium; e, details of puparium. (From 

 Chittenden.) 



feeders, and the majority are leaf -miners, stem borers or 

 gall producers. The leaf -mining forms occur in four genera; 

 Agromyza, Phytomyza, Cerodonta and Napomyza. There 

 are approximately 194 species which mine leaves. Many of 

 them are European species. 



The egg. The eggs of this family are soft, white and 

 smooth, and vary in form from broadly oval to sub-cylindri- 

 cal. All, as far as known, are inserted within the tissues 

 of the leaf. 



