HIBERNATION. 27 



To the insects which hibernate in the larval state belong, 

 of course, in the first place, all those which exist under that 

 form for more than one year. There are also many larvae 

 which, though their term of life is not a 3^ear, being hatched 

 from the egg in the Autumn, necessarily pass the Winter in 

 that state. Many of these, living in the ground or in the 

 interior of trees, need no other refuge than the holes which 

 the}- constantly inhabit ; some, as the aquatic larvae, merel}^ 

 hide themselves in the sides or muddy bottom of their native 

 pools, while others seek a retreat under moss, dead leaves, 

 stones and the bark of decaying trees. Most of these can 

 boast of no better Winter quarters than a simple unfurnished 

 hole or cavity ; but a few, more provident of comfort, prepai^e 

 themselves an artificial habitation. A very considerable 

 number of insects, especially beetles, hibernate in the perfect 

 state. 



Toward the close of Autumn the whole insect world is in 

 motion. A general migration takes place. The various 

 species quit their usual haunts and betake themselves in search 

 of secure retreats. Different species, however, do not select 

 precisely the same time for making this change of abode. 

 For instance, many lady birds, field bugs and flies are found 

 out of their Winter quarters even after the commencement of 

 frost, while others make good their resting place long before 

 severe cold has been felt. 



The sites chosen by different perfect insects for the period 

 of their repose are very various. Some are content with insin- 

 uating themselves under any large stone, a collection of dead 

 leaves, or the moss of the sheltered side of an old wall or 

 bank. Others prefer for a retreat the lichen or ivy covered 

 interstices of the bark of old trees, the decayed bark itself, 

 especially that near the roots, or bur\- themselves deep in the 

 rotten trunk, and a very great number penetrate into the earth 

 t9 the depth of several inches. The aquatic tribes burrow in 

 the mud of their pools, but some of these are occasionally 

 found under stones. Most insects hiliernate in solitude. 



