Because they have wings covered with very fine scales: (lepis, a scale - pteron, a wing;) as the butterfly : - 2,570 species.
Because they have reticulated or nerved wings:
(neuron, a nerve - pteron, a wing;) as the dragon-fly:
- 174 species.
Because they have membraneous wings: (hymen, a film - pteron, a wing;) as the bee : - 1,265 species.
Because they are two-winged: (dis, twice - pteron, a wing;) as the common gnat: - 692 species.
Because they have no wings: (a, privative - pteron, a wing;) as the spider and the centipede : - 679 species.
About thirty years ago, the recorded number of insects amounted to about eleven thousand; but a great additional number has since been discovered and described: Humboldt says 44,000.
Because insects must eat, - not solely to satisfy hunger, but also to destroy carrion, to annihilate other insects, to extirpate weeds, etc.; an admirable provision, to the execution of which, besides the almost incalculable number of species, the extremely rapid multiplication of many, the unexampled voracity of others, and the quickness with which digestion is carried on in their very short intestinal canal, all tend to contribute. Thus, it is known, that a caterpillar will, in twenty-four hours, consume more than three times its own weight. - Blumenbach.
Because they are found on almost all warm-blooded animals ; and even the larger insects, as bees, chaffers, etc. are infested by peculiar kinds of lice. There are but few plants, also, (such as, perhaps, the yew, savine, and most tree-mosses,) which do not serve for the abode and support of known insects. Many again, as the oak, are frequented and inhabited by more than a hundred distinct species. Generally, however, as insects are diffused over the earth, the residence of individual species is not less frequently limited to a very small number of animals and plants, or even particular parts of them.
Because some destroy numerous kinds of weeds in the bud, or extirpate them when full grown. Others feed on carrion, live in dung, etc, and thus destroy, disperse, and change noxious animal substances; on the one hand, obviating the infection of the air; and on the other, promoting the fertilization of the earth. It is in this way, for instance, that flies are so serviceable in warm climates. So again, innumerable insects effect the impregnation of plants in a very remarkable manner.