40 



true to-morrow, for no one can tell what 5^ear or in what part of the 

 country any one of these, even the one that seems the most insignifi- 

 cant, may suddenl}' come to the front and commit serious depredations 

 over a considerable area. Besides this, tlie}^ are all of them so obscure 

 in appearance and their effect on the plants they attack so subtile and 

 hidden from the eyes of the farmer that he is unaware of his loss until 

 on threshing his grain he finds that it does not turn out well and the 

 kernels are light and shriveled. It is like the thefts of a trusted ofl5- 

 cial — they are not missed until, by accident, perhaps, the defalcations 

 are discovered, when we are struck with amazement at their magni- 

 tude and ask ourselves and each other how it is possible for such 

 things to go on continually through a long series of years and escape 

 detection. The financial loss occasioned by an unusually disastrous 

 outbreak of these pests can be estimated, but it is a mistake to sup- 

 pose that such losses constitute more than a very small percentage of 

 the amount annually filched from the farmers by these insidious foes 

 of his crops. It is not so much the big losses that occur at rare inter- 

 vals, and of which we read much in the public press, but the infinite and 

 perpetual leaks from this source that pull down the farmer's profits — 

 leaks that, as has been shown, he may readily prevent in a most inex- 

 pensive manner. It is for the very reason of their obscurity and 

 insidious attacks, coupled with the magnitude of the losses caused by 

 them through a long series of years, that has prompted a study of 

 their habits and the publication of the facts in the present form. 



THE TWO-WINGED GRAIN AND GRASS FLIES. 



The insects included under this head are true flies, having only two 

 wings and their young are maggots without feet, eyes, or jaws. They 

 belong to the famih' Oscinida?, containing a large number of species 

 with variable food haV)its, some of them not attacking plants, but living 

 on the cast skins of other insects, shells of insect eggs, and in the bur- 

 rows made in plants hy other insects. Some of them are leaf-miners, 

 others live in galls on grasses, while still others live underground on 

 the roots of plants. Still others, that are known to live in the stems 

 of grain and cause more or less destruction by their attacks, will be 

 here considered, though it must not be supposed that there are not 

 still others of such depredators of which we as yet know nothing. 



Our grain-affecting species are to be found in the genera Meromyza, 

 Chlorops, Elachiptera, and Oscinis. It is to the last that the very 

 destructive frit-fly (Oscinis frit) of England and Europe belongs and 

 which is so terribly destructive to grain crops in those countries. The 

 habits of Meromyza americana have been pretty well studied and we 

 now have a fairly good knowledge of its life history and habits; but of 

 the most of the other species belonging to the above genera we only 



