STATE AGRICULTURAL SOCIETY. 
763 
MIDGE. FLY. EFFECT OF MOISTURE AND DRYNESS ON IT. 
other galls in this first bottle giving out parasites afterwards. 
In forty-five days after they were inclosed, (May 1st) five flies 
came out in the bottlo out doors, their parasites subsequently ap¬ 
pearing as in the first case. From the bottle in the ice house, 
four galls were now taken and placed out doors in a separate bot¬ 
tle. From these two flies hatched fifteen days afterwards. 
Finally, the bottle in the ice house with the six remaining galls 
was taken thence and placed out doors on the first of June, and 
a fly came out therein on the twelfth of June, nothing more com¬ 
ing from these galls afterwards. 
Thus it will be seen that the Willow gall midge, which natu¬ 
rally comes abroad about the first of May, can by cold be 
delayed in its appearance till some six weeks after that time, or 
by warmth it can be brought out six weeks before its time. 
Indeed, it may be brought out at any time during the winter, by 
placing the galls in a warm room, as I have repeatedly done. 
It is also worthy of notice, that these insects had made no ad¬ 
vance during the ten weeks they were lying in the ice house, as 
the galls were twelve days in giving out their insects in June, 
when the temperature out doors was near what it was within 
doors in March, where they had hatched in ten days time. It 
thus appears that when they are in a temperature which is down 
nearly to the freezing point, these midges and probably most 
other insects remain stationary. 
The most important characteristic of this fly of the wheat 
midge is its extreme sensitiveness to the hygrometric condition 
of the atmosphere. Moisture is its life ; dryness smothers and 
suffocates it. It is •active and perfectly at home in a humid 
atmosphere; a dry atmosphere it cannot breathe, it cannot en¬ 
dure. This statement is confirmed by numerous observations, 
and this simple fact serves to explain most of the other things 
which have been noticed and recorded in the economy and habits 
of these insects. 
In consequence of this sensitiveness the fly is unable to remain 
about the wheat heads during the day time in ordinary weather. 
The warmth of the sun renders the atmosphere so dry there that 
it cannot abide it. It therefore drops itself down to the lower 
part of the stalks of the grain, in which shaded situation the 
humidity arising from the ground renders the atmosphere conge¬ 
nial to it. It there remains at rest during the heat of the day, 
