478 ARTICULATED ANIMALS. 



the thorax in the Myriapoda ; but it is distinct in all the other insects which are fur- 

 nished with six legs. It incloses the viscera, the sexual organs, and exhibits nine or 

 ten segments, but of which some are often concealed, or very considerably reduced in 

 size. The organs of generation are situated at its posterior extremity, except in the 

 Dragon- flies and luli. The terminal segments of the abdomen compose, in many 

 females, an oviduct (oviscapt, Marcel de Serres), which is either retractile or always 

 exserted, and more or less complicated, and which is employed as a borer or augur. 

 It is replaced by a sting in the females [and neuters] of many Hymenoptera. 



After coupling, which ordinarily takes place but once, the female deposits her eggs 

 in the places best suited for their preservation, so that when the young are hatched they 

 find themselves in the midst of suitable food. The female also frequently collects pro- 

 visions for them. These maternal cares often excite our surprise, and most clearly 

 exhibit to us the instinct of insects. In the very numerous societies of many of these 

 creatures — such as the Ants, White Ants, Wasps, Bees, &c. — the individuals com- 

 posing the majority of the assembly, and which, by their labours and vigilance, support 

 these societies, have been considered as neuter individuals, or without sex : they have 

 been consequently named workers, or mules. It is, however, now ascertained that 

 they are females, of which the sexual organs, or ovaries, are not fully developed, but 

 which may become fruitful if a modification of their food, at a certain period of their 

 early existence, takes place, whereby these organs are developed. 



The eggs are sometimes hatched in the abdomen of the mother, which is then termed 

 viviparous. The number of generations in a year, of a species, depends on the dura- 

 tion of each : more commonly, there is but one or two in the year. A species, under 

 similar circumstances, is the more common in proportion as its generations succeed 

 each other in rapidity, and the female is more fruitful. 



A female Butterfly, after coupling, deposits her eggs, from which are hatched, not 

 Butterflies, but animals with a very long body, divided into rings, a head provided with 

 jaws, and several little eyes, having very short legs, of which six are scaly and pointed, 

 placed in the front of the body, and the others, variable in number, membranous, and 

 attached to the hind rings. These animals, called Caterpillars, live a certain time in 

 this state, and change the skin several times. At length, however, a period arrives, 

 when, from this skin of the Caterpillar, issues a very different being, of an oblong form, 

 without distinct limbs, and which soon ceases to move, and remains a long time appa- 

 rently dead, and dried up, under the name of a Chrysalis. On regarding it, however, 

 mere closely, we perceive, in relief, upon the outer surface of this Chrysalis, the lines 

 which represent all the parts of the Butterfly, but in proportions difi^erent from those 

 which these parts will, at a future day, acquire. After a longer or shorter period, the 

 skin of the Chrysalis bursts ; the Butterfly comes forth, moist, soft, with flaccid and 

 short wings, but in a few instants it dries, its W'ings grow, become stronger, and it 

 becomes fitted for flight. It has six long legs, antennae, a spiral proboscis, composite 

 eyes : in a word, it does not in the least resemble the Caterpillar from which it had 

 sprung, for it is ascertained that the changes in its state are nothing else than succes- 

 sive developements of the parts contained within each other. Such are the metamor- 

 phoses of insects. The first state is named the larva, the second the nymph \j)upa], 

 and the third the perfect state limagol. It is only in the last- mentioned state that the 

 insect is fitted for propagation. 



