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THE FLY-WEEVIL. 



290 



xtH 



the gentlemaa in Angumois does not mention to happ^-n 



For a few days after the chryfalides are mc- 



rope. 

 tamorphofcd into flies, thefe flies copulate, and impregnate 

 more found grams of wheat with their eggs, which again 

 produce worms, chryfaHdes, and new parent flies; where- 

 by the number of worms is fucceffively multipUed, and the 

 mifchief increafed during thew^irm weather, but ceafes in 

 cold, and returns again in the fpring. The fpring flies 

 are fuppofed to proceed from worms, hatched at that time 

 it) eggs, preferved in the grain through the winter; be- 

 cauie they are preceded by worms, are fliort lived, and 

 never feen 'till the feafon is become warm; and becaufe 

 very cold -winters have been obferved to lefl'en the number 

 of flies the enfuingfummer, which is fuppofed to be from 

 the eggs being frozen, and deftroyed in the grain. The 

 gardeners in Europe preierve their fruit trees, and fruit, 

 by carefully deftroying the nefls of thofe infe£ts which in^ 

 jure them, and when the eggs of infesSs are depofited in 

 ■any known place, or thing, it certainly would not be im- 

 prad:icablc to prevent any mifchief arifing from them 

 Therefore in tliis enquiry it may be ufeful to know, how 

 and where the wheat fly is preferved; if in the wheat, it 

 may be difcovered by the following experiments. Expofe 

 to fevere frofl a quanty of wheat, that had been fly injured 

 in the fall; afterwards put this wheat, and an equal quan 



tity of the fame parcel, that had not been froiled, into dif 

 ferent veffels, and keep them a due time in the degree of 

 warmth requifite to hatch the eggs. If the fads are as 

 above fuppofed, living worms will be found in the latter, 

 but not in the former. 



The eggs of thefe flies have fometimes hatched, when 

 the feafons have been extreme hot and moifl, in the corn 

 flanding in the field. ' But this rarely happens 'till after it 

 is flacked or houfed, and a fermentation cnfues. 



The common method of preferving wheat from harvcft 

 till it is threflicd, efpecially in places moil fubjedt to the 

 flieS) is in Hacks in the field. Thefe flacks afford a re- 



' markable 



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