278 [Senate 
sowing as securing the crop from injury. Though I did not see the 
fly abroad until the 16th of June, it was then present in such swarms, 
and had already deposited its eggs so profusely, that I think it must 
have commenced appearing quite early in that month. It, moreover, 
continued to be abundant until about the middle of July, and speci¬ 
mens were occasionally met with a month longer. Certainly if it is 
usual for it to be spread out over such an extent of time, it will be 
vain to rely upon the time of sowing to insure a crop against its rava¬ 
ges. Some observations in the foreign accounts also throw light upon 
this subject. Mr. Shirreff says, in 1829 the fly appeared June 21st j 
“ and from the vast numbers of them then seen, it is probable a few of 
them may have been in existence some days previous.” Their eggs were 
seen June 23d, and must therefore have been deposited on the evening 
of the 22d. “ The flies were observed depositing eggs on the 28th, 
and finally disappeared on the 30th of July, thus having existed 
through a period of thirty-nine days,” and depositing eggs during thir¬ 
ty-seven of these days. I know not how Mr. S. could be certain that 
the fly had disappeared for the season on the 30th of July, for his ac¬ 
count is dated the first day of August. For a few days only after 
their first appearance, he tells us, they frequented the couch-grass as 
well as the wheat. Was not this because there was not at that time a 
sufficient quantity of wheat in bloom to accommodate the number of 
insects that were then out 1 And Mr. Markwick distinctly states that 
it was after the grain had been harvested, that he found the larva; in 
the wild oats. Were not the parent flies then obliged to resort to this 
plant, because all the wheat had become mature ere they had comple¬ 
ted depositing their eggs 1 These facts certainly make it appear as 
though the fly is often abroad before the wheat commences blossoming, 
and continues till after it becomes mature. 
Is there then, no mode by which the flowering grain can be shield¬ 
ed from the ravages of the fly 1 This is a subject on which I have 
bestowed much thought; and I am not now prepared to tell the rea¬ 
der what he must do , but I will briefly inform him what I shall do, 
upon the first occasion that calls for it. A method is sometimes re¬ 
sorted to abroad, for saving grain fields from the depredations of cer¬ 
tain insects of peculiar habits. A rope is drawn along over the 
grain by two men walking at a brisk pace ; which rope thus knock¬ 
ing against the heads of the grain, causes the depredators to drop 
