
IMPORTANT INSECTICIDES: DIRECTIONS FOR THEIR PREPA- 
RATION 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, aud ease of appli- 
cation. These are not covered by patent, and in general it 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 Foop 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. Omitting for the present purpose the many 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 distinet principles of food economy 
of insects, viz, whether they are biting (mandibulate) or sucking (haus- 
tellate), each group involving a special system of treatment. 
INJURY FROM BITING INSECTS. 
The biting or gnawing insects are those which actually masticate and 
swallow some portion of the solid substance of the plant, as the wood, 
bark, leaves, flowers or fruit. They include the majority of the injurious 
larvee, many beetles, and the locusts. 
- For these inseets direct 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, and should always be employed except where the 
parts treated are themselves to be shortly used for the food of other 
animals or of man. 
