
IMPORTANT INSECTICIDES: DIRECTIONS FOR 
THEIR PREPARATION AND USE. 
INTRODUCTORY. 
Without going minutely into the field of remedies and preventives 
for insect depredations it is proposed to give in this bulletin brief 
directions concerning a few of the insecticide agents having the widest 
range and attended with the greatest usefulness, economy, and ease 
of application. These are not covered by patents, and in general it is 
true that the patented articles are inferior, many of the better of them 
being 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 insects will be included as are 
necessary to illustrate the principles underlying the use of the several 
insecticide agents. 
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 exceptional 
forms 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, viz, whether the insect is a biting (mandibulate) or a suck- 
ing (haustellate) species. Each group involves 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 grasshoppers. (See fig. 1.) 
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