INSECTA. 237 



feet those organs at a particular epoch while they are young, 

 they become fruitful. 



The ova are sometimes hatched in the abdomen of the 

 mother ; she is then viviparous. The number of generations 

 in a year depends on the duration of each of them. Most 

 commonly there is but one or two. A species, all things being 

 equal? is so much the more common, as one generation suc- 

 ceeds more rapidly to another, and as the female is more pro- 

 lific. 



A female Papilio or Butterfly, post coitum, lays her eggs, 

 from which are hatched, not Butterflies, but animals with an 

 elongated body, divided into rings, and a head furnished with 

 jaws and several small eyes, having very short feet, six of 

 which are anterior, scaly, and pointed, the rest varying in 

 number and membranous, being attached to. the posterior an- 

 nuli. These animals, called caterpillars, live in this state for 

 a certain period, and repeatedly change their skin. An epoch, 

 however, arrives, when from this skin of a caterpillar issues a 

 totally different being, of an oblong form and without distinct 

 limbs, which soon ceases to move and remains a long time ap- 

 parently desiccated and dead under the name of a chrysalis. 

 By close examination we may discover on the external surface 

 of this chrysalis, lineaments which represent all the parts of 

 the Butterfly, but under proportions differing from those they 

 are one day to possess. After a longer or shorter period, the 

 skin of the chrysalis splits, and the Butterfly, humid and soft, 

 with flabby short wings, issues from it a few moments, how- 

 ever, and it is dry, the wings enlarge and become firm, and 

 the perfect animal is ready for flight. It has six long legs, an- 

 tennae, a spiral proboscis, and compound eyes in a word, it 

 has no resemblance whatever to the caterpillar, from which 

 it has originated, for it is ascertained that these various 

 changes are nothing more than the successive development of 

 parts contained one within the other. 



This is what is styled the metamorphosis of Insects. In 

 their first condition they are called larvas, in their second 



