568 DIPTEBA. 



mucli smaller and more common species, inhabiting the 

 locust-tree. During the month of August, some of the 

 leaves of this tree will be found to have one edge thickened 

 in substance and rolled over, so as to form an oblong cavity, 

 cylindrical in the middle, and tapering at each end. This is 

 the work of the larvae or young Cecidomyians, two or three 

 of which will sometimes be found in each cavity, where also 

 they complete their transformations. The larva is a maggot 

 of a whitish color, faintly tinged with orange, particularly 

 towards the head. The pupa or chrysalis is not contained 

 within a cocoon. The fly measures three twentieths of an 

 inch in length. It is orange-colored, with dusky antennae 

 and wings, three dusky lines on the thorax, and two dusky 

 spots on the sides of the body. An apparent interruption 

 in one of the veins of the wings, noticed by Professor Hal- 

 deman, is not peculiar to this insect, but may be seen, more 

 or less distinctly, in our other species of Cecidomyia. 



The Hessian fly was scientifically described by Mr. Say, 

 in 1817, under the name of Ceci- 

 rig ' ~ '" domyia destructor* (Fig. 257). It 



obtained its common name from a 

 supposition that it was brought to 

 this country, in some straw, by the 

 Hessian troops under the command 

 of Sir William Howe in the war 

 of the Revolution.! This supposi- 

 tion, however, has been thought to 

 be erroneous, because the early in- 

 quiries made to discover the Hessian 

 fly in Germany were unsuccessful ; and, in consequence 

 thereof, Sir Joseph Banks, in his report to the British gov- 

 ernment, in 1789, stated that " no such insect could be found 

 to exist in Germany or any other part of Europe." £ It 



* Journal of the Academy of Natural Sciences of Philadelphia, Vol. I. p. 45. 

 t Dobson's Encyclopaedia, Vol. VIII. p. 491. 



+ Encyclopaedia Britannica, and Dobson's Encyclopaedia, Vol. VIII., Article 

 Hessian Fly. 



