xI] Flies 149 
Wheat Midge (Cecidomyia tritict). 
This pest damages wheat by injuring the grain 
and causing it to become very shrivelled. In an 
ear that is attacked we shall find inside the chaff a 
number of small yellowish or orange coloured legless 
grubs about 4 inch long. These suck the juice of 
the grain. Just before harvest some of the grubs go 
down into the soil and pupate, forming orange coloured 
pupae. Others remain in the ears and are harvested; 
on threshing these may be found in the screenings. 
The flies come out about June and lay their eggs 
usually in the evening on the developing flowers. 
The flies have yellowish bodies and very noticeable 
black eyes. 
Remedial Measures. 
Deep ploughing has proved effective in checking 
this pest, as the delicate fly is unable to make its way 
through the soil. All infected screenings should be 
burnt. 
Warble Fly. 
The well-known warbles on cattle are caused by the 
maggots of flies known as Hypoderma lineata and 
Hypoderma bovis. The affected cattle have lumps or 
abscesses on their backs. Each of these lumps contains 
the maggot of a warble fly. 
The life history of the warble fly has not yet been 
worked out in all its stages. It was formerly supposed 
that the fly laid its eggs on or in the backs of cattle, 
and that the maggot bored its way into the skin or was 
