WHEAT FLIES 261 



on the outside of the ear; but as impatient of bright 

 light, sheltering themselves from the sun's rays 

 among the husks. 



Our English naturalists were for many years of 

 opinion, that the insect called the Hessian-fly, so 

 destructive to wheat crops in America, belonged to 

 the same family (Muscidce) with the common house- 

 fly; and Mr Mark wick, an intelligent naturalist, by 

 a series of observations on a British fly (Chlorops 

 pumilionis, MEIGEJN) which attacks the stems of 

 wheat, created no little alarm among agriculturists. 

 Mark wick 'a fly is less than a fourth of an inch in- 

 length, with dark shoulders striped with two yellow 

 lines, and the maggot is white. He planted roots of 

 wheat containing larvas 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.* 



, The Hessian fly (Cccidomyia d'strurtor); 5, Markwick fly 

 ((. htoreps fmmilionii,} magnified. 



It now appears that Markwick was altoget her 

 mistaken in identifying his insect with the Hessian 

 fly (Cecidomyia destructor, SAY), which has been 

 accurately described by Mr Say in the ' Journal of 

 the Academy of Natural Sciences of Philadelphia' 



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



