48 OUT OF DOORS. 



winter have passed away, so that the fingers of the 

 searcher are not chilled into uselessness, a circumstance 

 which is very apt to occur when the enthusiastic ento- 

 mologist pursues his task in mid-winter. Moreover, 

 towards the spring a vast number of tree-inhabiting 

 insects become developed, and make their way towards 

 the open air before they undergo their last change, so 

 that at this time of year we may find almost imme- 

 diately under the bark many insects which at other 

 times would be buried deeply in the Wood. 



Taken roughly, all the creatures which are found 

 under the bark may be divided into two classes, 

 namely, those which have resorted there for shelter 

 during the cold months of winter, and those which 

 feed upon the bark or the substance of the tree itself. 

 The former can always be found under the bark of old 

 trees, especially oaks and willows. The latter, how- 

 ever, are the most prolific in insect life. In many old 

 willows the bark is slightly separated from the trunk 

 for many feet, and although no external sign be given of 

 this fact, the hollow sound which is returned when the 

 outside of the tree is tapped is a sufficient proof. On 

 carefully removing one of these sheets of bark from 

 the tree a most extraordinary sight is often presented. 



The space between the bark and wood is a vast 

 camp of insect armies, their white and glittering tents 

 being set so closely together that there is not room 

 for a finger's tip between them. Under the bark also 

 flourish certain colonies of flat white cryptogams, 



