142 ' WONDERS OF ORGANIC LIFE. 



slug those combined conditions of atmosphere and 

 light which are most grateful. All are nocturnal. 

 Spiders, scorpions, and centipedes, etc., hy- 

 bernate ; as also do woodlice, millepedes, etc. ; 

 and the same observation applies to nume- 

 rous insects, not only in their larva and chry- 

 salis state, but in their perfect or imago condi- 

 tion. The housefly, the bee, the humble bee, 

 the wasp, the molecricket, the ant, are familiar 

 examples — to which we may add many beetles. 

 Different species pass the winter in different 

 retreats ; some crowd together, and like frogs 

 become torpid in associated numbers ; some 

 seek a solitary cell. The aquatic beetles bur- 

 row into the mud of their pools. Whatever 

 may be their respective winter-quarters, the 

 selected dormitory is admirably adapted to the 

 constitution, mode of life, and wants of the 

 occupant. The degree of cold which insects in 

 their different states while torpid are able to 

 endure is various. The pupae of the cabbage 

 butterfly, (Papilio brassicce,) exposed to fourteen 

 degrees below the freezing point of Fahrenheit, 

 became converted in a lump of ice ; yet these 

 pupae, after being cautiously thawed, underwent 

 their usual metamorphosis, and became winged 

 butterflies. We must not, however, suppose 

 that the pupse or chrysalides of all butterflies 

 can sustain such a degree of cold with impunity ; 

 yet duly sheltered, the vital principle enables 

 many to endure, not only the winter of our 

 climate, but of more northern latitudes. This 

 shelter the caterpillar ever seeks before changing 



