580 
PIPTERA. 
CECIDOMYIIDjE. 
Minute delicate flies. Antennae long, generally with whorls of hair on 
the joints, especially in the male. Legs long and slender ; tihice without 
spurs ; coxce not elongated. Wings broad, rather hairy, with veins jew 
and weak ; the media usually absent. 
These minute flies, though very inconspicuous in the adult condi¬ 
tion, sometimes make their presence severely felt while in their imma¬ 
ture stages from the damage they inflict on various crops in America 
and Europe. The most widely known of these pests is probably the 
4 ‘ Hessian fly, 5 ’ a destructive enemy of wheat in Europe, America, and 
New Zealand. 
The larva of this fly ( Cecidomyia destructor, Say) lives between the 
leaf and the stem of the wheat 
attack that it bends over, 
and gives practically no seed. 
When full grown the animal 
before becoming a pupa exudes 
a substance which stiffens into 
an outer covering, giving it 
rather the appearance of a 
flaxseed, this resting stage being hence often called the “ flax-seed 
stage.” As a general rule preventive measures are difficult, as they 
depend on destroying as far as possible, by hand-picking the affected 
plants containing pupae, the first brood of the flies, which necessitates early 
recognition of the attack. Under natural conditions the flies appear 
to be kept in check by hymenopterous parasites, and probably do 
serious damage only when these parasites are from some cause 
rendered inefficient. 
Besides those forms whose larvae live in the above manner there are 
very many others which lay their eggs in various other parts of plants. 
The presence of the egg or larva, or the injection of some irritating fluid, 
results in a kind of local inflammation which produces a gall on the plant 
and in this gall the larva developes. To facilitate the laying of the eggs 
in the proper place the ovipositor in some species is very much elongated. 
The larvse of Cecidomyiids are somewhat curious ; they are small- 
headed maggots often red or pink, tapering slightly at both ends, with 
