248 CLASS viii. 



which Cuvier, as stated above (p. 33), divided the entire Animal 

 Kingdom. We allude to the Type of Articulate Animals, which 

 may be separated into two divisions. The first division includes 

 articulate animals without jointed feet (apoda, the Annulata), the 

 other articulate animals with feet (Condylopoda] . Again, articulate 

 animals with limbs (Insects of LINNAEUS) are divided into three 

 classes, of which the first, immediately to be treated of, retains the 

 name of Insects; the two other classes, those of the Arachnids and 

 of the Crustaceans, comprehend those animals which LINNJEUS con- 

 sidered as wingless Insects. 



Insects (in the narrower meaning of modern systematic Zoology) 

 are mostly provided with wings ; but the presence of these organs 

 of motion does not constitute the character of the class. That is to 

 be sought for in the head distinct from the trunk, to which two 

 antennae are attached, and in the Respiration by means of air-canals 

 distributed internally through the body and generally divided into 

 very fine branches. The first of these characters distinguishes the 

 Insects from the Arachnids in which the head and thorax form a 

 single piece, and which have no antennas, the other distinguishes 

 them from the Crustaceans, whose respiratory organs are gills or 

 other external appendages. 



The names Insecta, notched animals, and in Greek evro^a, have 

 all the same meaning. From the last is derived the word Entomo- 

 logy (Insect- Science). 



The species belonging to this class are very numerous : in this 

 respect no other class can be compared with Insects. In treating 

 therefore of this class we must keep within strict limits, that we may 

 not too greatly extend our work in the estimation of those who take 

 less interest in this special part. 



We will first describe the external structure of these creatures a 

 little more precisely The body of the six-footed Insects, which 

 make up by far the largest portion of this class, is separated into 

 three parts : head, trunk, and abdomen. On the head, besides the 

 parts about the mouth, the antennae and eyes are distinguished. 



By Antennce are understood moveable jointed threads, which, 

 unconnected with the oral organs, are attached to the head, usually 

 close to the eyes. The number of joints is very different; in But- 

 terflies, for instance, very large, in Beetles, mostly eleven, &c. All 

 insects in the perfect condition or last period of life have two 



