4 
E. A. ORMEROD—PREVENTION OF INSECT-INJURY. 
by clearing off hairy larvae ; and many others would probably be 
utilized much more if we had some short account to show the many 
amongst us who are not practical Ornithologists the points where 
they help us, and also in cases of unusually large appearance of 
birds, as of titmice brought together by aphis-presence, rooks 
searching for grubs in the pastures, sea-gulls, starlings, or others, 
how to be able to distinguish between friends and foes, or species 
which are devoting themselves temporarily to good service. 
Where there is a great amount of insect-attack, or where it may 
reasonably be supposed that insect-presence is doing harm although 
unseen, there the aggregation of birds should by all means be 
protected; but as a general thing the amount to which the insecti¬ 
vorous birds should be encouraged and increased beyond the natural 
balance, is a very difficult subject. It is often overlooked that these 
insectivora feed on the insect-parasites of our insect-pests as well as 
on the pests themselves, and consequently kill our allies as well as 
our enemies. This point is brought forward in the lteport of the 
Agricultural Commission of Ontario, a work replete with useful 
information and suggestion, and deserves serious consideration. 
Yarious kinds of parasitic Hymenoptera are of such service in 
keeping down the caterpillars of various pests, as for instance the 
maggots of the ichneumon flies which hold the cabbage-butterfly in 
some sort of check, that their special protection and multiplication 
is advised; and not to go too much into detail, we may refer to 
ladybirds that keep down the aphides, dipterous flies that also 
serve us, and many other species. All these have their uses, and 
we should soon feel the want of them. 
Other kinds of insect-feeders have their uses also, such as the 
mole, the bat, the shrew, and even the squirrel, in destroying the 
“ cased” larvae and pupae of the pine saw-fly; but nevertheless 
it seems to me that any movement to decidedly increase the number 
of the insect-destroyers beyond the natural balance is not certainly 
desirable. 
Of course when attack is present any means of getting rid of it 
is useful, and a great deal may often be done by working on some 
one special habit, which may frequently be found to exist in very 
different kinds of insects, and different stages of their lives. For 
instance various kinds of beetles, as cockchafers and weevils, also 
the caterpillars of various kinds of moths and sawflies, fall to the 
ground if their food-plant is shaken; and if we look at the large 
class of injury caused to leafage by these pests, we shall find that 
much good might be done by simply shaking or gently striking the 
infested boughs or small trees. 
This is a regular part of German forestry or gardening; in 
America “jarring” the trees is equally looked to as a means of 
getting rid of the pests, and in the case of our vegetable crops also 
there are agricultural methods of carrying out the plan, and it may 
safely be advised whenever any plant (or tree of a size to which 
the plan is applicable) is infested, to try immediately what effect 
a good shaking, syringing, or careful beating will have in clearing 
