56 AN ACCOUNT OF BRITISH FLIES. 
above the second joint.” This seems to be generally the case, but 
it 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 teniopus) 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 larve 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 down, 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. destructor is 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. 
