360 INSECTA. 



ORDER V. 

 COLEOPTERA. 



Coleopterous Insects have four wings, the two superior of which 

 resemble horizontal scales, joining in a straight line along the inner 

 margin; the inferior wings are merely folded transversely and co- 

 vered with others, which form cases or covers for them, usually de- 

 nominated the elytra. 



Of all Insects, these are the most numerous and the best known. 

 The singular form and brilliant colouring of many species, the vo- 

 lume of their bodies, the greater solidity of their teguments, which 

 facilitates their preservation, the numerous advantages, which the 

 study derives from the various forms of their external organs, &c., 

 have secured to them the particular attention of naturalists. 



Their head presents antennae of various forms, and almost always 

 composed of eleven joints; two compound eyes, but none simple; 

 and a mouth consisting of a labrum, two mandibles, usually of a 

 scaly substance, two jaws, each furnished with one or two palpi, and 

 of a Idbium formed of two pieces, the mentum and the ligula, and 

 accompanied by two palpi, commonly inserted into the latter. 

 Those of the jaws, or when they have two, the exterior ones, never 

 consist of more than four joints; those of the lip usually have three. 



The anterior segment of the trunk, or that which is before the 

 wings, usually called the thorax, bears the first pair of legs, and is 

 much larger than the two other segments. The latter are intimately 

 united with the base of the abdomen, and their inferior portion or 

 pectus gives insertion to the second and third pairs of legs. The 

 second, on which the scutellum is placed, is narrowed before, and 

 forms a short pedicle which fits into the interior of the first, and 

 serves as a pivot, on which it moves. 



The elytra and wings arise from the lateral and superior edges 

 of the metathorax. The elytra are crustaceous, and when at rest, 

 join along their internal margin, and always horizontally. They 

 almost always conceal the wings, which are wide and transversely 

 folded. Several species are apterous, but the elytra still exist. 

 The abdomen is sessile or united to the trunk in its greatest width. 

 It is composed externally of six or seven annuli, membranous above, 



