412 



RAVAGES OF INSECTS, 



British fly ( Chlorops pumilionis, Meigen) whicli attacks tlie 

 stems of wheat, created no little alarm among agriculturists. 

 Markwick's fly is less than a fourth of an inch in " length, 

 with dark shoulders strijDed with two yellow lines ; and the 

 maggot is white. He planted roots of wheat containing 

 larvae in a small flower-pot, and covered them with gauze. 

 Each stem produced one of the above flies. The crop of 

 wheat attacked by this maggot, though at first it appeared 

 to fail, turned out well in consequence of numerous side 

 shoots. It is only the early wheat sown in October that is 

 affected by it.* 



a The Hessian-fly (C'ecido?nyia des(Jv<cio9-); 6, Mark wick fiy ^Chlorops piimiUonis), 

 ' inugnifled. 



It now appears that Markwick was altogether mistaken 

 in identifying his insect with the Hessian-fl}^ (Cecidrmiyia 

 destructor. Say), which has been accurately described by 

 Mr. Say in the ' Journal of the Academ}^ of Natural Sciences 

 of Philadelphia' for 1817. It is a little larger than our 

 wheat-fly, more slender in the body, has longer legs, and is 

 not orange, but black and fulvous. The female deposits 

 from one to eight or more eggs on a single plant of wheat, 

 between the sheath of the inner leaf and the stem nearest 

 the roots ; in which situation, with its head towards the 

 root or first joint, the young larva passes the winter, eating 

 into the stem, and causing it to break.f 



The devastation committed by the Hessian-fly seems to 

 have been first observed in 1776, and it was erroneously 

 supposed that the insect was conveyed among straw by the 

 Hessian troops from Germany. It was first noticed in the 

 wheat fields of Long Island, from which it spread gradually 



* Mag. Nat. Hist., July 1829, p. 292, 



t Ibid., vol. i. p.. 228. 



