56 AN A ceo UNT OF BRITISH FLIES. 



above the second joint." This seems to be generally the case, but 

 ic is not at all uncommon to find them as high as the fourth joint, 

 and as low as the first. They never are present in the ear. The 

 "ribbon-footed corn-fly" {Chlorops tccniopiis) feeds in the ears of 

 corn, and has very often been mistaken for the maggot of the 

 Hessian fly. 



The attack of this insect is easily seen in a field of wheat, the 

 straw bending down just above the abode of the maggot or maggots, 

 for there may be several in very bad attacks at one point. It is not 

 unusual to find a gall, or swelling, above the infested part. 



The larvce living on the juices of the plant weaken the stem, and 

 although the ear and upper part of the straw may become stunted, 

 the infested part becomes so weak that the upper part with the ear 

 bends dovvn, as if beaten down by rain and wind, thus doing 

 immense damage to the crops. Hundreds of acres of wheat and 

 barley are destroyed in this way in America, but at present we have 

 not suffered much from its ravages, the loss in infested areas in 

 England being from one to twelve bushels per acre. 



This insect, which is two-brooded in America, has only one brood 

 in England, and so here we are only subject to one attack. Young 

 autumn-sown wheat, which is so much devastated on the American 

 continent, is free from the attack here. This second form of attack 

 is very different to the former. The maggot, which has developed 

 from the autumn brood, lies just above the root, at the surface, and 

 before assuming the " flax-seed " state it comes to lie between the 

 leaves and the stalk. This second form of attack may be known by 

 the dark colour of the leaves, their great breadth, and the absence of 

 the central leaf. The whole wheat plant becomes stunted and rank- 

 growing. The first brood appears in May and June, the second in 

 August and September. According to Professor Riley the Hessian- 

 fly " is very injurious only under conditions where two annual genera- 

 tions are pretty uniformly produced ; and he is satisfied that in 

 England, as a rule, only one generation will be produced."* The 

 same entomologist, in " Insect Life," says that " there is very little 

 danger of any such injury in England as is suffered in America and 

 in portions of Continental Europe." Whether this is correct time 

 will show ; certainly the climatic conditions of our island are favour- 

 able to its increase. 



The distribution of C. desfniciorh very wide ; in America it extends 

 from the Atlantic to Kansas and from the Gulf of Mexico to the 

 St. Lawrence, doing an immense amount of damage. It was known 



* Griffiths' " Diseases of Crops," p. 114. 



