570 DIPTEEA. 



In a communication by Mr. J. W. Jeffreys, published in 

 the sixth volume of Buel's " Cultivator," it is stated, that 

 soon after the battle of Guilford, in North Carolina, the 

 wheat crops were destroyed by the Hessian fly in Orange 

 County, through which the British army, composed in part 

 of Hessian soldiers, had previously passed. Although it is 

 possible that, in this instance, the chinch-bug may have been 

 mistaken for the Hessian fly, the remark shows how preva- 

 lent was the belief respecting the introduction of the latter. 

 The foregoing statements, taken in connection with the 

 habits of the Hessian fly, induce me to think that the com- 

 mon opinion relative to its origin is deserving of some 

 credit. 



The head, antenna?, and thorax of this fly are black. 

 The hind body is tawny, more or less widely marked with 

 black on each ring, and clothed with fine grayish hairs. 

 The egg-tube of the female is rose-colored. The wings are 

 blackish, except at the base, where they are tawny and very 

 narrow ; they are fringed with short hairs, and are rounded 

 at the tip. The legs are pale red or brownish, and the 

 feet are black. The body measures about one tenth of an 

 inch in length, and the wings expand one quarter of an inch, 

 or more. After death, the hind body contracts and becomes 

 almost entirely black. 



The Hessian fly is a true Cecidomyia, differing from Lasi- 

 optera in the shortness of the first joint of its feet, and in 

 the greater length of its antennae, the bead-like swellings 

 whereof are also more distant from each other, especially 

 in the males. According to Mr. Herrick, the number of 

 the joints of the antennae varies " from fourteen to seven- 

 teen, besides the basal joint, which appears double." As 

 in other species of Cecidomyia, the form of the joints differs 

 according to the sex; those of the male being globular, 

 and those of the female, except at base, oblong oval. In 

 both they are surrounded with whorls of short hairs. The 

 difference in the antennae of the sexes has been pretty well 



