CLASS INSECTS. 387 



light. In another species of lampyris inhabiting Italy, the 

 individuals of both sexes are at the same time winged and 

 luminous; but this singular property is especially remark- 

 able in certain taupins inhabiting the hot regions of America, 

 and which produce, whilst they vault in the obscurity, a 

 natural illumination of the happiest effect ; the women fre- 

 quently place them in their hair as ornaments, and it is 

 asserted that the Indians make use of them to point out the 

 way during the night. In one lampyris, the light comes from 

 certain spots situated over the two or three last rings of the 

 abdomen; whilst in the taupins it comes from analogous 

 spots over the prothorax or corslet. It appears that the 

 insect can vary at will the intensity of the phosphoric light, 

 and that it is connected with the action of the oxygen upon a 

 fatty matter secreted by the phosphorescent organs. 



530. The sexes are distinct in these animals, and there 

 exist often great differences between the male and the female: 

 the common lampyris has already offered us an example 

 (Figs. 366, 367). Almost all insects lay eggs ; nevertheless, 

 some are viviparous. .There often exists at the extremity of 

 the abdomen of the female a dart, a wimble, or some other 

 organ, destined to form holes adapted to receive the eggs ; and 

 by an admirable instinct the mother uniformly deposits these 

 in a place where the young will find themselves in proximity 

 with the food they require, even although it be in most cases 

 not the kind which the parent lives on. 



In youth, insects change their skin several times, and pre- 

 sent almost always a phenomenon of the most remarkable 

 kind, of which, however, we have already seen an example in 

 the batrachia. Most of them, on quitting the egg, neither 

 resemble their parents nor what they will themselves after- 

 wards become, and undergo, before arriving at the perfect 

 state, changes so considerable as to constitute a true meta- 

 morphosis. 



In general, insects pass through three conditions, quite 

 distinct, which have been named the larva state or condition 

 (Fig. 368), the nymph state (Fig. 369), and the perfect state 

 (Fig. 370) ; but the changes they undergo are not always 

 equally great. Sometimes these changes render the animal 

 altogether unrecognizable, at other times they consist only 

 in the development of wings ; and these various degrees of 

 transformation are known by the names of complete meta- 

 morphoses or of semi-metamorphoses. 

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