Tlie Progress of the Hessian Fly. 
443 
or brushed off with the stubble. A few of these self-sown corn- 
plants, calletl " volunteer " in America, may serve to infest a 
whole district ; therefore it is of little use taking steps to de- 
stroy stubble unless self-sown corn-plants are eradicated at the 
same time. 
Here it will be convenient to remark that rye is subject to the 
attack of the Hessian Fly in America and in Russia. From 
this it may be reasonably inferred that it will infest rye-plants 
in Great Britain. Rye is sown very early in the autumn for 
horse-food in the spring, and sometimes for ewes and lambs. 
It would be very dangerous to sow rye in the vicinity of in- 
fested fields, as the plants would serve to carry on the insect 
throughout the winter. Though it has not been found upon 
rye-plants in this country, there is a strong presumption that it 
would be harboured upon them, and due precaution should 
be taken. The same remarks apply to winter barley for 
early food for ewes and lambs and other sheep, which is 
put in generally at the end of August, thus affording a suit- 
able host for the eggs of the insect. If winter barley is sown 
in infested localities, it is of no use postponing the sowing of 
wheat. 
Many pupa-cases have been seen among the cleanings, 
cavings, and short refuse straw, after thrashing and dressing 
infested wheat and barley. From some of these, kept in glass 
bottles, flies have come, and in the greater part of the pupa- 
cases the pupBC appeared to have full vitality, though they had 
been in ricks upon the straw from August until March. In 
threshing and cleaning wheat and barley from fields known to 
have been infested, or from fields near to those infested, close 
examination of the refuse from the threshing and dressing 
machine should be made. In the event of pupa-cases being 
found, all this should be at once burnt. Straw from infested 
fields should be stacked as closely as possible and used only for 
litter, and in the winter months. In the recommendations 
published by the Agricultural Department it is also urged that 
if wheat and barley upon the straw of which pupa-cases are dis- 
covered, are threshed out in the fields, infinite care should be 
taken to destroy all the cleanings and cavings, and to stack 
the straw tightly together, or remove it at once and use it for 
litter. When ricks are made near fields, their outsides should 
be trimmed with shears according to the practice of neat farmers, 
and the short straws burnt. 
Where wheat-plants show symptoms of failing and of losing 
plant in the late autumn and winter, they should be examined. 
If larv.T, or pupa-cases, are seen, it would be well to put sheep 
upon the wheat as soon as possible in the spring, that they may 
