336 BEES' NESTS. 



cave, and rolling them up so as to form a case : in 

 this she deposits an egg. The mouth of the cave 

 is then covered with five or six circular patches of 

 leaves ; fragments of wood like saw-dust are then 

 lodged over them, and the remainder of this chan- 

 nel filled up with other patches of the leaf, requir- 

 ing, perhaps, twenty or more to accomplish it. 

 This requires no great effort or time to effect, the 

 active workman labouring with great assiduity ; 

 but the conveyance of the fragments which form 

 the nest seems to be attended with much fatigue, 

 for I have often seen this bee, with its burden 

 drawn between its legs, retire to rest against the 

 bole of a tree, or upon a wall, the abdomen con- 

 tracting and dilating with rapidity, like the sides 

 of a creature after exertion. Having acquired 

 strength, her labours are resumed. All these 

 layers and saw- dust are designed to secure the 

 larva from punctures by the ichneumon fly, 

 which is constantly seeking for caterpillars of 

 various insects, in which to deposit her egg : this 

 hatches and grows with their growth, feeding on 

 their vitals, consuming them and perfecting itself. 

 But all these guards effectually prevent the purport 

 of the fly, the larva remaining safe in its asylum 

 until sufficiently matured ; it then penetrates through 

 all these layers, assuming the form of the parent 

 bee. I believe the rose and the cytisus laburnum 

 only are made use of for these circular layers. In 

 this specimen the larva was perfected ; but at an 

 earlier period, an egg would have been found, with 



