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 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 FOOD HABITS TO REMEDIES. 
For the intelligent and practical employment of insecticides it is 
necessary 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 distinct principles of food 
economy of insects, viz, whether they are biting (mandibulate) or suck- 
ing (haustellate), 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 injuri- 
ous larve, many beetles, and the locusts. 
For these insects 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, 
