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floAV following on excessive rainfall. Sudden rainfall 
after drought often destroys great numbers of cater¬ 
pillars, sometimes by producing violent purging, but 
whether this is from the external moisture chilling the 
exposed larva, and clogging the breathing pores, or that 
the flow of watery sap disagrees with the larval con¬ 
stitution, is not clearly known. The dew of the evening, 
or a light rainfall, or mist, helps us also, so to say, 
mechanically, for at these times dressings will adhere to 
the insects which otherwise would fall off without 
being of service to us. For this reason the late evening 
or the early morning are the best times for such appli¬ 
cations to many kinds of attacks, and a want of con¬ 
sideration of this is often the cause of the same kind of 
dressing failing, or succeeding, at different times quite 
unaccountably to the operator. This is especially the 
case with Turnip Fly—moisture clogs its leaping-legs, 
and, until it is dry again, the flea-like springs that put 
it out of reach of dressings, or shake off what may fall 
on it, are an impossibility. 
There is often some one portion of the economy or 
habits of an insect by which it falls into our power, and, 
by looking to this point (which sometimes runs through 
many of one family), we may get rid of the visitation 
easily, surely, and without much outlay. We find that 
caterpillars of various kinds of Sawflies make their 
cocoons just below the surface of the ground; therefore 
removing the surface-soil beneath Gooseberry bushes, or 
beneath Pine trees, where the cocoons are usually formed 
(in masses near the trunk) is very serviceable. The 
attack of Corn Sawfly, which goes into pupa in the Corn 
stem at the ground level, may be prevented by collecting 
and burning the stubble. With regard to many larvae 
that feed within the seeds, leaves, or stems, the simple 
plan of burning the infested plants, instead of throwing 
them to rubbish heaps, where the creatures can complete 
their development, or go down for the purpose into the 
earth beneath, would, in the most literal sense of the 
word, 'prevent much coming attack. Wheat Midge in 
