1. Aptera (Fleas and Lice).
2. Diptera (Gnats, Flies, &c.)
3. Hemiptera (Bugs, &c.)
4. Lepidoptera (Butterflies and Moths).
5. Orthoptera (Grasshoppers, Crickets, Cockroaches, &c.)
6. Hymenoptera (Bees, Wasps, &c.)
7. Thysanoptera (Thrips cerealium).
8. Neuroptera (Libellula, or Dragon-fly; Ephemera, or May-fly; Phryganea, or Alder-fly).
9. Coleoptera (Beetles).
We shall commence the history of the various orders by examining the Aptera.
APTERA.
Insects of this order are without wings, and the name is derived from two Greek words, α, privative, and πτερον, wing, indicating the negative character which constitutes this order. [9] It consists of Fleas and Lice. The Flea (Pulex), of which De Geer formed a separate group, and called Suctoria, includes several species.
The common flea (Pulex irritans, [Fig. 17]) has a body of oval form, somewhat flattened, covered with a rather hard horny skin of a brilliant chestnut brown colour. It is the breaking of this hard skin which produces the little crack which is heard when, after a successful hunt, one has the happiness to crush one of these parasites between one's nails.
