CLASS I. INSECTA. 



637 



imperceptible without the aid of a microscope. You now view it furnished with wings capable 

 of rapid and extensive flights ; of its sixteen feet, ten have disappeared, and the remaining six are 

 in most respects wholly unhke those to which they have succeeded; its jaws have vanished, and 

 are replaced by a curled-up proboscis, suited only for sipping liquid sweets; the form of its head 

 is entirely changed ; two long horns project from its upper surftice ; and instead of twelve invis- 

 ible eyes, you behold two, very large, and composed of at least seventeen thousand convex lenses, 

 each supposed to be a distinct and eff"ective eye ! 



" Were you to push your examination further, and by dissection to compare the internal con- 

 formation of the caterpillar with that of the butterfly, you would witness changes even more ex- 

 traordinary. In the former you would find some thousands of muscles, which in the latter are 

 replaced by others of a form and structure entirely different. Nearly the whole body of the 

 caterpillar is occupied by a capacious stomach. In the butterfly it has become converted into 

 an almost imperceptible thread-like viscus ; and the abdomen is now filled by two large packets 

 of eggs, or other organs not visible in the first state. In the former, two spirally-convoluted 

 tubes were filled with a silky gum ; in the latter, both tubes and silk have almost totally van- 

 ished, and changes equally great have taken place in the economy and structure of the nerves 

 and other organs. 



"What a surprising transformation! Nor was this all. The change from one form to the 

 other was not direct. An intermediate state not less singular intervened. After casting its skin, 

 even to its jaws, several times, and attaining its full growth, the caterpillar attached itself to a 

 leaf by a silken girth ; its body greatly contracted, its skin once more split asunder, disclosing 

 an oviform mass, without exterior mouth, eyes, or limbs, and exhibiting no other symptom of 

 life than a slight motion when touched. In this state of death-like torpor, and without tasting 

 food, the insect existed for several months, until at length the tomb burst, and out of a case not 

 more than an inch long and a quarter of an inch in diameter, proceeded the butterfly before you, 

 which covers a surface of nearly four inches square. Almost every insect which you see has un- 

 dergone a transformation as singular and surprising, though varied in many of its circumstances." 

 From these striking and beautiful general views, we must pass to a particular description of 



the wonderful races under consid- 

 eration. Insects, in their perfect 

 state, are distinguished from the 

 other articulate animals by the 

 possession of six legs and two an- 

 tennae, and by the division of the 

 body into three distinct regions, 

 the head, thorax, and abdomen, as 

 exhibited in the annexed figure. 



The second of these divisions 

 bears the organs of motion. In- 

 sects respire by trachea?, are gen- 

 erally furnished with wings, and 

 almost always undergo a series of 

 transformations or metamorjihoscs 

 before arriving at their mature 

 and reproductive form. 



Their bodies are composed of 

 distinct rings or segments, and 

 these are generally of a horny con- 

 sistency, united to each other by 

 I a membraneous skin which gives flexibility to the whole. In some cases, however, the skin is 

 j of a softer texture ; but even in these it presents sufficient firmness for the attachment of the 

 I muscles, and the tubes composing the limbs are generally of a harder consistence than the rest 

 i of the integument. The number of segments of which the body of an insect is normally com- 

 VoL. II. — 68 



Antennae 

 Eyes 



1st pail- of Legs 



1st pair of Wings 

 2d pair of Legs 



2d pairof Wings 



3d pair of Legs 



Head. 



Thorax 



Abdomen. 



Tarsus 



ANATOMY OP THE EXTERNAL SKELETON OP AN INSECT. 



