CHAPTER III 
THE CLASSIFICATION OF INSECTS 
As has been explained in the preceding chapter, insects are primarily classi¬ 
fied on the basis of their postembryonic development. Insects with incom¬ 
plete metamorphosis, that is, those which do not undergo a non-feeding, 
usually quiescent, pupal stage in their development are believed to be more 
nearly related to each other than to any of the insects which undergo a so- 
called complete metamorphosis. So they are spoken of collectively as the 
Hemimetabola, while all the insects with a distinct pupal stage are called 
the Holometabola. But when one has collected an adult insect, as a fly 
or moth or grasshopper, and wishes to classify it, this primary classification 
based on character of development often cannot be made for lack of informa¬ 
tion regarding the life-history of the particular insect in hand. The next 
grouping is into orders, and this grouping is based chiefly on structural 
characters, and corresponds to one’s already more or less familiar knowledge 
of insect classification. Thus all the beetles with their horny fore wings 
constitute one order, the Coleoptera; the moths and butterflies with their 
scale-covered wings another order, the Lepidoptera; the two-winged flies 
the order Diptera, the ants, bees, wasps, and four-winged parasitic flies 
the order Hymenoptera, and so on. So that the first step in a beginner’s 
attempt to classify his collected insects is to refer them to their proper orders. 
Now while entomologists are mostly agreed with regard to the make-up 
of the larger and best represented orders, that is, those orders containing 
the more abundant and familiar insects, there are certain usually small, 
obscure, strangely formed and more or less imperfectly known insects with 
regard to whose ordinal classification the agreement is not so uniform. While 
some entomologists incline to look on them simply as modified and aberrant 
members of the various large and familiar orders, others prefer to indicate 
the structural differences and the classific importance of these differences 
by establishing new orders for each of these small aberrant groups. Most 
entomologists of the present incline toward this latter position, so that whereas 
Linnaeus, the first great classifier of animals, divided all insects into but 
seven orders, the principal modern American * text-book of systematic entp- 
* Comstock, J. H., A Manual of Insects, 1898. 
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