The Classification of Insects 
53 
mology recognizes nineteen distinct ones. This does not mean, of course, that 
twelve new orders of insects have been found since Linnaeus’s time, although 
two or three of the orders are in fact founded on insects unknown to him, 
but means that certain small groups classified by Linnaeus simply as families 
in his large orders have been given the rank of distinct orders by modern 
systematists. And as our knowledge of insects and their relationship to 
each other is certainly much larger now than it was one hundred and fifty 
years ago, we may feel confident that the many-order system of classifica¬ 
tion is more nearly a true expression of the natural interrelationships of 
insects than was the old seven-order system. But not all entomologists 
agree on the nineteen-order system. Few, indeed, still use the Linnsean 
system, but many believe that the division of the insect class into nineteen 
orders gives too much importance to certain very small groups and to some 
others which are not markedly aberrant, and these entomologists recognize 
a lesser number of orders, varying with different authors from nine to about 
a dozen. In this book we shall adopt the nineteen-order system as used 
in Comstock’s Manual. In the first place the author believes that this classi¬ 
fication best represents our present knowledge of insect taxonomy; in the 
second place this is the classification taught by nearly all the teachers of 
entomology in America. 
To determine the order to which an insect belongs we make use of a 
classifying table or key. In the Key to Orders which follows this para¬ 
graph, all the insect orders are characterized by means of brief statements of 
structural features more or less readily recognized by simple inspection of 
the superficies of the body; to determine some of the conditions a simple 
lens or hand-magnifier will be needed. The orders are so arranged in the 
key that by choosing among two or more contrasting statements the student 
may “trace” his specimen to its proper order. Inspection of the Key with 
an attempt or two at tracing some familiar insect, as a house-fly, moth, or 
wasp whose order is already known, will make the method of use apparent. 
It must be borne in mind that young insects, such as caterpillars of moths, 
grubs of beetles, and the wingless nymphs of locusts, dragon-flies, etc., cannot 
be classified by this key. Indeed the young stages of most of the insects 
which we know well as adults are unknown to us, and there is, besides, such 
manifold adaptive variety in the external structure of those forms which we 
do know that no key for the classification into orders of immature insects 
can now be made. 
