(COCCIDIDÆ).
INTRODUCTORY.
Insects are divided by naturalists into several principal orders, the distinguishing marks of which are generally very well defined—for example, the butterflies and moths belong to the order Lepidoptera, the dragon-flies to the Neuroptera, the common house-flies to the Diptera, and so on. These orders are founded upon the characters and arrangement of the wings. They are subdivided into families, and these again into genera and species. One of the orders is that of the Hemiptera, which is composed of the two following sections:—
Hemiptera-Heteroptera, including the bugs, water-beetles, &c.
Hemiptera-Homoptera, including the crickets, cuckoo-spits, plant-lice (Aphides), leaf-hoppers (Psyllids), scale-insects (Coccids), &c.