78 INSECTS AND MAN 



HESSIAN FLY 



One of the most destructive insects, if not the most 

 destructive, taking all the world over, is the Hessian fly, 

 Cecidomyia destructor. A noted pest of wheat, this minute 

 gnat-like insect, less than one-tenth of an inch in length, 

 does not disdain rye and barley when wheat is not to 

 be found. In America alone, it takes toll of the cereal 

 crops, in some parts, to the extent of fifty per cent., and, in 

 1900, its total damage in that country was estimated at 

 $100,000,000. In England this destructive pest is not un- 

 known, but is fortunately rare. Its debut in this country 

 occurred, in 1886, in Essex. The name Hessian fly was 

 given to Cecidomyia destructor in America, because it was 

 thought that it had been introduced, during the war of the 

 Revolution, by the Hessian soldiers, and the belief was 

 probably well founded. Its European range extends from 

 France to Russia, and from Norway to Italy. In 1888, too, 

 it spread to New Zealand. How, one may ask, can such a 

 minute and apparently helpless insect reach America and 

 New Zealand, separated as they are from Europe by thou- 

 sands of miles of ocean ? We shall see that the pupae of 

 this fly, popularly called "flax seeds," are deposited on 

 wheat, which may eventually be converted into straw and 

 used as bedding for horses, or packing for merchandise. 

 The Hessian troops landed near New York in 1776-77, 

 used straw as bedding, and, as the introduction of the fly 

 took place at the same time, it is highly probable that the 

 flax seeds found their way into the country on this bedding. 

 Similarly, it is believed that the pupao were conveyed into 

 New Zealand on straw used as packing material, which 

 was carelessly scattered, instead of being destroyed. 



The fly (fig. 17) belongs to the order Diptera, or two- 

 winged flies, and to the family Cecidomyidce, or gall gnats, 

 so called because the majority attack living plants, with 

 the consequent formation of galls. The female fly is 



