THE PUPA OR CHRYSALIS. 119 



the fine Moth Satumia Spini, and a small Tortrix ; 

 while the Moth of the Silk-worm positively breaks 

 its way out of its silky enclosure by means of its 

 "eyes," these being at the time the only hardened 

 part of its body ; and their raised facets, acting like 

 little files, soon clear a passage for the more tender 

 parts of the body and wings. It is on this account 

 that it becomes necessary to destroy the Moth in 

 its chrysalis, by scalding, when it is wished to pre- 

 serve the silk, which would otherwise be rendered 

 worthless. 



Among Ants, the "Workers" have the in- 

 stinctive duty assigned to them of letting out their 

 congeners from their chrysalides when the proper 

 time arrives. This they do by biting through a 

 ligament which makes the shell so solid, that the 

 young Ant would never be able to make his way 

 out unaided ; and the worker, whose duty it is to 

 attend to this essential business, never mistakes the 

 precisely proper time for this operation. 



The Caddis Worm, when about to pass to the 

 pupa state, covers up each end of its house with a 

 silken tissue. When the time of pupation is over, 

 the insect appears to become furnished with false 

 mandibles, with which it cuts through the silk 

 in front of the head, which it then puts forth, 



