INSECTS INJURIOUS TO VEGETATION. 



tains in 1797; from their progress through the country, having 

 apparently advanced about thirty miles every summer. Wheat, 

 rye, barley, and even timothy grass, were attacked by them; 

 and so great were their ravages in the larva state, that the 

 cultivation of wheat was abandoned in many places where 

 they had established themselves.* In a communication by 

 Mr. J. W. Jeffreys, published in the sixth volume of Bviel'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 prevalent was the belief respecting the 

 introduction of the latter. The foregoing statements, taken 

 in connexion with the habits of the Hessian fly, induce me to 

 think that the common opinion relative to its origin is deserv- 

 ing 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 Hes- 

 sian fly is a true Cecidomyia, differing from Lasioptera 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 seventeen, besides the basal joint, which 

 appears double." As in other species of Cecidomyia, the form 



* " Encyclopaedia Britannica," and Dobson's " Encyclopaedia," Vol. VIII., 

 article Hessiaa Fly. 



