VI PREFATORY NOTE 



Downes and Mr. Treherne of the Canadian Dominion Ento- 

 mological Service. Dr. Frost wishes to acknowledge help 

 in the determination of specimens from Dr. J. M. Aldrich, 

 Dr. Adam Boeving and Mr. S. A. Rohwer, all of the U. S. 

 National Museum. 



I, as senior author, wish to assume responsibility for 

 the omission of the name of the describer of the species after 

 each scientific name. 



Our undertaking has been threefold. We have endeav- 

 ored to provide (1) an un technical introduction to the 

 study of leaf-mining insects, intelligible to the general 

 reader; (2) an account of their natural history sufficiently 

 detailed to be useful to the working ecologist; and (3) lists 

 of the leaf-miners, of their food plants, and of technical 

 papers concerning them adequate for the needs of the 

 specialist. Thus we have undertaken to make more avail- 

 able to students, the rich but hitherto widely scattered results 

 of many excellent investigations in this interesting eco- 

 logical field. 



Here there is much that should be of interest to the 

 general biologist. The mandibulate leaf-mining larvae 

 show a convergence in form that is almost without a parallel 

 elsewhere. They also present an unique example of hyper- 

 metamorphosis that hitherto has been almost or quite 

 ignored by all the text books in their discussions of that 

 subject. Leaf -mining moth larvae are not ordinary cater- 

 pillars; at least, the sap-feeders are not. The mouthparts 

 they have developed for shearing and sap drinking and the 

 form of head associated therewith are quite their own. 



Any one with a taste for natural history will find interest 

 in observing how these tiny creatures get their living, find 

 their shelter, keep their dwelling places clean and sanitary, 

 provide for all the shifts of stage and station, and manage 

 the ordinary business of their lives. Their ways are quite 

 unique in the animal world. 



James G. Need ham. 



Ithaca, April 20, 1926. 



