112 DISEASES OF CROPS. 



is one of the most formidable foes of wheat and barley- 

 crops; but it does not attack oats. This dipterous fly 

 has been known in the northern continent of America 

 for over a hundred years. The earliest recorded attacks 

 of the true Hessian fly in England was in the summer 

 of 1886 ; although, according to Dr. K. Lindeman {Die 

 Ilessenfliege in RusslandP), it was first observed in Russia 

 six years earlier than in Great Britain. As C. destructor 

 is often the cause of a wholesale destruction of the wheat 

 crops in America, it has earned the name of the " North 

 American scourge " ; but up to the present date the 

 Hessian fly has not done much damage in our islands, 

 where it has confined its attacks to the eastern coun- 

 ties. Although this fly is " an insect of moist climates 

 and mild latitudes," Dr. C. V. Riley says : " that there 

 is very little danger of any such injury in England as 

 is suffered in America and in portions of Continental- 

 Europe." ^ Since the visitation of this fly in Great 

 Britain, the damage done by it has been estimated at a 

 loss of one to twelve bushels of grain per acre. The 

 female fly lays its eggs upon the stems of wheat and 

 barley, i.e., between the stem and the leaf-sheath. The 

 eggs (pointed at both ends) are about the one-fifteenth of 

 an inch in length, and of a red colour. The female ^ de- 

 posits singly about eight eggs, and then takes flight. 

 These eggs are glued together by means of a sticky 

 secretion. The white larvae, which are devoid of legs, 

 are hatched from the eggs in fourteen days. After estab- 

 lishing themselves, as a rule, just above the second joints, 



' Bulletin de la Society ImpSriale des Naturalistes de Moscou, 1887. 



2 Insect Life, vol. i. p. 133. 



' Each female lays about 230 eggs in a season. 



