Some Accomit of the Wheat Fly, 451 



both fell to the ground. The earwig also destroys the larvae, 

 three of which I successively presented to a earwig, which de- 

 voured them immediately, and fell from the wheat ear before 

 I could offer a farther supply. 



The abode of the pupa during winter is a subject of doubt ; 

 and with a view of determining this point, a quantity of wheat 

 ears was selected which had been ravaged by the larvae last 

 summer, and kept in a round stack through the winter. A 

 portion of the ears was kept in the vinery of Mr. John Ferme, 

 Haddington, and the remainder in Mungoswells dining- 

 room ; but in neither case was a fly obtained. On the 24-th of 

 June, when the flies were extremely numerous, and perhaps 

 when the pupa was assuming the aurelia state, I examined, in 

 the evening, a grass field which had carried a wheat crop, 

 injured by the larvae in the preceding year, and found the fly 

 abounding ; on a grass field adjoining, which had been pas- 

 ture the preceding year, flies were not found; on a potato 

 field, which had been wheat the previous year, many flies were 

 seen ; on one which had been oats, flies were not visible ; and 

 on naked fallow, which had been wheat the previous year, 

 there were many flies ; on that which had been oats, there 

 were not flies : in short, wherever wheat had grown the pre- 

 ceding year, flies were found, and seldom met with in other 

 situations. From such evidence it may be concluded, the 

 pupae remain generally in the soil during winter ; but probably 

 they occasionally pass the winter in wheat ears. Being un- 

 able to devise means for checking the devastations of the wheat 

 fly, and conceiving those that have hitherto been recommended 

 unavailing for the purpose, I am still not without hope that 

 some of your correspondents may be able to supply the desi- 

 deratum. 



Patrick Shirreff, 

 Mungoswells^ East Lothiariy 

 Aug, 1. 1829. 



