

ee ere 
IMPORTANT INSECTICIDES: DIRECTIONS FOR THEIR PREPARATION 
AND USE. 
Without going minutely into the field of remedies and preventives 
for insect depredators, it is proposed to give in this bulletin brief direc- 
tions concerning a few of the insecticide agents having the widest range 
and attended with the greatest usefulness, economy, and ease of appli- 
cation. These are not covered by patent, and in general if is true that 
the patented articles are inferior, and many of the better of them are 
in fact merely more or less close imitations of the standard substances 
and compounds hereinafter described. Only such brief references to 
food and other habits of the insects covered will be included as are 
necessary to illustrate the principles underlying the use of the several 
insecticide agents recommended. 
RELATION OF FOOD HABITS TO REMEDIES. 
For the intelligent and practical employment of insecticides it is nec- 
essary to comprehend, the nature and method of injury commonly due 
to insects. Throwing aside, for the present purpose, the innumerable 
special cases of injury which necessitate peculiar methods of treatment, 
the great mass of the harm to growing plants from the attacks of insects 
falls under two principal heads based on distinct principles of food 
economy of insects, viz, whether they are biting (nandibulate) or suek- 
ing (haustellate), each group involving a special system of treatment. 
BITING INSECTS, 
Under this head comes the injury resulting from the actual consump- 
tion by the mastication and swallowing of the solid substance of some 
portion of the plant, as the wood, bark, leaves, flowers, or fruit. This 
is done by the biting or gnawing insects, such as various larvee and 
certain beetles and locusts, causing an injury at once apparent and 
readily observed and understood. 
For all these insects poisons such as the arsenicals, which may be 
safely applied to the leaves or other parts of the plant attacked and 
which will be swallowed by the insect with its food, furnish the surest 
and simplest remedy. A direct poison should, therefore, be employed 
for all biting insects which feed externally, except where the parts 
attacked are themselves to be shortly used for the food of other ani- 
mals or of man. 
