40 



MECHANICAL FUNCTIONS. 



Fig. 25. 



The Silk Worm. Of the silk worm, Fig. 24, represents 

 Fig. 24. the full grown 



caterpillar, and 

 Fig. 25 the chrys- 

 alis which it pro- 

 duces, the latter 

 being deprived 



of its cocoon in order to show its form 

 and size. 



The chrysalis remains in this state 

 for various lengths of time, depending 

 on the species to which it belongs, or 

 on the warmth to which it is exposed. Some Insects 

 continue in this state for years, while others emerge and 

 become perfect in a week, or two. During this time 

 the organs which are to serve them in their future, and 

 more elevated career, are preparing ; although very little 

 change can be observed in the size, or appearance of the 

 chrysalis. 



When the time arrives that these several organs are 

 completely formed, and the butterfly is ready to assume 

 its rank among the beautiful and lively inhabitants of 

 the air, then it is that the insect bursts the shroud in 

 which it has so long been enclosed, and comes forth in 

 form and colors so beautiful, and in spirits, so joyous 

 Fig. 26. and sportive, as amply 



to compensate for its 

 inglorious, and degrad- 

 ed origin. 



Our Insect has now 

 arrived to its imago, 

 perfect, or butterfly 

 state, the Moth, of the 

 Silk Worm being rep- 

 resentes by Fig. 26. 

 Through these several changes do all the butterflies, 

 and a great proportion of the Insects, properly so called, 

 pass. Some of them enjoy their perfect state only for a 

 short time, a few hours ; while others continue to dis- 

 play their beauties, and wanton among the sweets of the 



How long do insects remain in the chrysalis state, 1. 



