14 
INTRODUCTION. 
Pupa with the cases of the wings and of the legs indistinct, 
and soldered to the breast. 
Some kinds of caterpillars are domestic pests, and devour cloth, 
wool, furs, feathers, wax, lard, flour, and the like ; but by far the 
greatest number live wholly on vegetable food, certain kinds being 
exclusively leaf-eaters, while others attack the buds, fruit, seeds, 
bark, pith, stems, and roots of plants. 
6. Hymenoptera (Saw-flies, Ants, Wasps, Bees, e.). 
Insects with jaws, four veined wings, in most species, the 
hinder pair being the smallest, and a piercer or sting at 
the extremity of the abdomen. Transformation complete. 
Larvae mostly maggot-like, or slug-like ; of some, caterpillar- 
like. Pupae with the legs and wings unconfined. 
In the adult state these insects live chiefly on the honey and 
pollen of flowers, and the juices of fruits. The larva? of the 
saw-flies ( Tenthredinidce), under the form of false-caterpillars and 
slugs, are leaf-eaters, and are oftentimes productive o’f much injury 
to plants. The larva? of the xiphydrians ( Xipkydriadce ), and of 
the horn-tails ( Uroceridce ), are borers and wood-eaters, and con- 
sequently injurious to the plants inhabited by them. Pines and 
firs suffer most from their attacks. Some of the warty excres- 
cences on the leaves and stems of plants, such as oak-apples, gall- 
nuts, and the like, arise from the punctures of four-winged gall-flies 
( Diplulepididce), and the irritation produced by their larvae, which 
reside in these swellings. The injury caused by them is, com- 
paratively, of very little importance, while, on the other hand, 
we are greatly indebted to these insects for the gall-nuts that are 
extensively used in coloring and in medicine, and form the chief 
ingredient in ink. We may, therefore, write down these insects 
among the benefactors of the human race. Immense numbers of 
caterpillars and other noxious insects are preyed upon by in- 
ternal enemies, the larva? of the ichneumon-flies (Evaniadte, Tchneu- 
monida, and Chalcidida), which live upon the fat of their victims, 
and finally destroy them. Some of these ichneumon-flics ( Ichneu - 
mones ovulorunt *) arc extremely small, and confine their attacks 
* Now placed among the Procloirupida. 
