36 



MECHANICAL FUNCTIONS. 



Fig. 25. 



Some insects 



89. The silk worm. Of the silk worm, Fig. 24 repre- 

 sents the full- Fig. 24. 



grown caterpil- 

 lar, and figure 

 25 the chrysalis 

 which it produ- 

 ces, the latter be- 

 ing deprived of its cocoon in order to show 

 its form and size. 



90. 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. 



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. 



91. 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 and 

 sportive, as amply to Fig. 26. 

 compensate for its in- 

 glorious and degraded 



origin. Our insect has 

 now arrived to its imago, 

 perfect, or butterfly state, 

 the moth, of the silk- 

 worm being represented 

 by Fig. 26. 



92. 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 thek beauties, and wanton among the sweets of the 



How long do insects remain in the chrysalis state ? 



