42 MECHANCAL FUNCTXOjrS. 



tigations ! Among the vulgar what eager curiosity, what 

 amazement." 



In the same spirit, Swammardam, who spent most of 

 his life in making observations on Insects, observes on the 

 same subject : " This history is so extraordinary, so ama- 

 zing in all its circumstances, that it might very well pass 

 for a romance, were it not built upon the most firm 

 foundations of truth," 



With respect to the size and appearance of the cater- 

 pillars and of the chrysalids they form, as well as the situ- 

 ations in which they are placed, and the time of remain- 

 ing in the torpid state, there are nearly as many varie- 

 ties as there are species of Insects. Some larvae de- 

 scend deep into the ground before they assume the tor- 

 pid state, and there remain three or four years before 

 they acquire wings. Others weave small cocoons, and 

 having thus covered themselves in beds of silk, then 

 change to chrysalids. These are sometimes construct- 

 ed in the earth, and sometimes attached to the sides of 

 fences, or the side of any vessel in which the worm is 

 confined. If confined in a glass vessel the observer may 

 witness the whole process of weaving the cocoon, and 

 of casting off the old skin, by which the chrysalis be- 

 comes apparent. 



The positions in which the larvae place themselves in 

 order to undergo this change, are also extremely various. 

 One species suspends itself to a leaf with it she ad down- 

 wards, being only fixed by the tail ; another passes a 

 rope of silk around its neck, and thus hangs in an oblique 

 position ; while others are simply glued in a horizontal 

 position, in any convenient place. 



Larva which feeds on the parsnip. There is a com- 

 mon larva which may be seen feeding on the leaves of 

 parsnips in the autumn, and which every one has noticed 

 en account of its handsome appearance, and the fetid 

 odor which it emits on being disturbed. The color is 

 greenish yellow, with bands of velvety black, and when 

 full grown it is nearly two inches long. The younger ones 

 of this caterpillar would at first be taken for a different 



What is said of the positions in which ehry salids are placed ? 



