762 
ANNUAL REPORT OF NEW YORK 
MIDGE. PLY. EFFECT OF HEAT AND COLD ON IT. 
few instances, and these, so far as I can recollect, havo always 
been where wheat was reared upon the adjoining lands the year 
before. Collectors will probably supply themselves with the 
males most readily, by searching for them in the last year’s 
wheat fields, at the time when the females first begin to appear 
abroad. 
Each fly probably lives about three weeks, under ordinary cir¬ 
cumstances. Thus they continue to be seen abroad about a 
month, their numbers lessening in July till towards the middle 
of that month, when the last ones disappear. But in years when 
this fly is very numerous, and especially if the season be a very 
wet one, they continue much longer. Thus, in the year 1845 a 
few of them continued to be met with upon the window panes, 
almost daily, until the sixteenth day of August. 
Many persons have the idea that these insects always come 
abroad at a particular time in the year, regardless of the state 
of the atmosphere. Hence, when warm genial weather brings 
vegetation rapidly forward in May or the early part of June, we 
frequently hear it remarked, that the wheat will hereby be so 
much forwarded, probably, that it will escape injury from the 
midge. But the truth is, the same temperature which advances 
or retards the progress of vegetation operates similarly and to 
an equal degree upon the insect tribes. A warm season hastens, 
a cold season retards insects and vegetation alike. Consequently 
each particular insect comes forth at the very time when the 
vegetation on which it preys is so advanced as to be adapted to 
its wants. Of this, as a general law of nature there is the full¬ 
est evidence. And that these small delicate insects are no excep¬ 
tion to this law is quite certain. 
In order to demonstrate the influence of temperature in matur¬ 
ing and bringing forth this group of insects to which the wheat 
midge pertains, on the sixteenth of March, when the Willow gall 
midge (Cecidomyia Salicis, Fitch) was passing from its larva into 
its pupa state, I gathered a quantity of the galls containing this 
insect, and inclosed them in three glass bottles, putting ten galls 
in each bottle. One of these bottles I placed in a room warmed 
night and day to a temperature of about 70 degrees of Fahren¬ 
heit’s scale ; the second I placed out doors, in the shade; the third 
bottle was placed on the surface of ice in an ice house. In ten 
days six flies had hatched from the galls in the warmed room, the 
