INTRODUCTION. 11 



ceous ground-beetles {CarahidcB), the diving beetles (DyfiscidcB), the 

 lady-birds {CoccinelladcB), and some others, are eminently serviceable 

 by preying upon caterpillars, plant-lice, and other noxious or destruc- 

 tive insects. The water-lovers {Hydrophilida;), rove-beetles (^Staphy- 

 liiiidoi), carrion-beetles (Silphadce), skin-beetles {Dermestadce, Byr- 

 rhidcB, and Trogida), bone-beetles (some of the NitiduladcE. and de- 

 rides), and various kinds of dung-beetles (Sphceridiadce, HisleridcB, 

 Geoirupidcz* , Coprididce*, and Ap/wdiadcB*), and clocks {Pimeliadce 

 and Blaptidm), act the useful part of scavengers, by removing car- 

 rion, dung, and other filth, upon which alone they and their larvae 

 subsist. Many Coleoptera (some Staphylinidce and Nitiduladce, Dia- 

 perididcE, some Serropalpidce, MycetophagidcB, Erofylidce, and En- 

 domychidcB) live altogether on agarics, mushrooms, and toadstools, 

 plants of very little use to man, many of them poisonous, and in a 

 state of decay often offensive ; these fungus-eaters are therefore to 

 be reckoned among our friends. There are others, such as the stag- 

 beetles (LucanidcE), some spring-beetles (Elateridce), darkling beetles 

 (TenebrionidcB), and many bark-beetles {Helopidce, CisteladcB, Serro- 

 paJpidce, (EdemeradcB, Cucujadcc, and some Trogositadcs), which, liv- 

 ing, under the bark and in the trunks and roots of old trees, though 

 they may occasionally prove injurious, mu§t, on the whole, be consid- 

 ered as serviceable, by contributing to destroy, and reduce to dust, 

 plants that have passed their prime, and are fast going to decay. And, 

 lastly, the blistering-beetlbs (CantharididcB) have, for a long time, 

 been employed with great benefit in the healing art. 



2. — Orthoptera (Cockroaches, Crickets, Grasshoppers, 

 &fc). Insects with jaws, two rather thick and opake upper 

 wings, overlapping a little on the back, and two larger, thin 

 wings, which are folded in plaits, like a fan. Transformation 

 partial. Larvae and pupae active, but wanting wings. 



All of the insects of this order, except the camel-crickets (Manii- 

 dce), which prey on other insects, are injurious to our household pos- 

 sessions, or destructive to vegetation. 



3. — Hemiptera {Bugs, Locusts, Plant-lice, ^c). Insects 

 with a horny beak for suction, four wings, vi'hereof the up- 

 permost are generally thick at the base, with thinner extremi- 



* All the Scarabffiidaj of my Catalogue, from Aleuchus to Geotrupes inclusive, 

 to which may be added many included in the genus ScarabcBus. 



