INSECTS. 



Schaefter, Scopoli, Geoffrey, Walckenaer, and Blainville, the 

 last two of whom derive the characters of the divisions from 

 the number of the legs ; and many writers, British as well as 

 foreign, have employed their pens and pencils in the description 

 and delineation of the animals of this extensive class. A list 

 of the chief of these will be found at the end of this volume. 



Latreille divides the class of Insects, as now restricted, into 

 eleven orders, of which, as his arrangement is followed in the 

 following summary, the characters will be given in their proper 

 place. The Parasita and Thysanoura, which Latreille pre- 

 viously arranged with the Arachnides, Dr Leach first added 

 to the class of Insects ; and the order Rhipiptera of Latreille 

 was originally instituted by Messrs Kirby and Spence, under 

 the name Strepsiptera, (from sr^ig, a turning or twisting, 

 and wng^r.) 



I. APTERA. 



ORDER I. THYSANOURA, ORDER III. SIPHONAPTERA. 

 II. PARASITA, 



II ALATA. * 



ORDER IV. COLEOPTERA, ORDER VIII. HYMENOPTERA, 

 V. ORTHOPTERA, IX. LEPIDOPTERA, 



VI. HEMIPTERA, X. RHIPIPTERA, 



VII. NEOROPTERA, XL DIPTERA. 



The body in insects is divided into three principal parts, the 

 head, the thorax, and the abdomen. The head, of which the 

 surface bears many names, according to the position of its parts, 

 such as the vertex, the forehead, the nose, the hood, and the 

 cheeks, supports the antennae, the eyes, and the mouth. The 

 antennas vary much in their composition and form. The ap- 

 terous insects, which form the first three orders, and the Cole- 

 optera, have never more than one kind of eyes ; but many of the 

 other orders, besides their compound eyes in facets, possess mi- 

 nute smooth ones (ocelli) in the form of brilliant points, sometimes 

 to the number of two, generally three, disposed in a triangular 

 form on the top of the head. These organs are always im- 

 movable. The mouth is composed of six principal pieces, of 

 which four are lateral, disposed in pairs, and moving transverse- 

 ly ; two other parts, opposed to one another, and filling up the 



