INSECTA. 561 



and, when at rest, their mesial margins join by a straight 

 suture. In some genera the elytrae are inseparably united 

 at their suture, and, in others, the elytrae at the base of the 

 suture are in contact, or lap over each other, while at the 

 extremity they recede from each other. The inferior pair 

 of wings are membranaceous, strengthened by anastomosing 

 ribs, and when at rest they are folded obliquely and trans- 

 versely and concealed under the elytra. When the insect 

 is about to fly, the elytra are raised, and remain fixed, while 

 the under wings unfold and execute their motions. In some 

 species, the under wings are imperfectly developed, or near- 

 ly obliterated, and in such cases the elytra are cemented at 

 the suture. The abdomen consists of six or seven rings, more 

 or less covered by the elytra, each having two sigmata, one 

 on each side. The antennae exhibit a great variety of cha- 

 racter in their situation, length, form, and number of the 

 joints. The eyes are compound, and two in number. 

 Each eye, in some, is divided by the continuity of the mar- 

 ginal band of the head. There are no ocelli. The instru- 

 menta cibaria are formed for cutting and masticating solid 

 substances. The food, however, which is consumed by 

 them, differs greatly, according to the species, in kind and 

 consistence, so that all the parts of the digestive system ex- 

 hibit extensive modifications of form. All the species are ovi- 

 parous. The larva is lengthened, frequently destitute of 

 antennae and eyes, having twelve or thirteen rings, a scaly 

 head, with the parts of the mouth similar to the perfect in- 

 sect. It has usually six feet. After continuing months, or 

 even years, in the larva state, the insect changes into a pupa 

 obtecta, through the skin of which the different members may 

 be distinctly perceived. The Coleoptera, in their perfect 

 state, require a regular supply of food, and live to a greater 

 age than other insects. They are very numerous in species 

 VOL. II. N n 



