INSECT A. 347 



nity are maintained, have been considered as being of neither sex. 

 They have also been designated by the terms of labourers and mules. 

 It is now known, however, that they are females not fully developed. 



The ova are sometimes hatched in the abdomen of the mother; 

 she is then viviparous. The number of generations in a year de- 

 pends on the duration of each of them. Most commonly there is 

 but one or two. 



A female Papilio, or Butterfly, 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 annuli. 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 appa- 

 rently 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 pos- 

 sess. 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 kw moments, however, and it is dry, the wings 

 enlarge and become firm, and the perfect animal is ready for flight. 

 It has six long legs, antennas, a spiral proboscis, and compound 

 eyes — in a word, it has no resemblance whatever to the caterpillar, 

 from whicli 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 pupce, nymphs or 

 chrysalides, and in the third perfect insects. 



All Insects do not pass through these three states. Those which 

 are apterous issue from the ovum with the form they are always to 

 preserve: they are said to be without a metamorphosis. Of those 

 that have wings, many experience no other change than that of re- 

 ceiving them; these are said to undergo a semi-metamorphosis. 

 Their larva resembles the perfect insect, with the single exception 



