HABITATIONS OF INSECTS. 435 



Cells composed of a similar membranaceous substance, 

 but placed in a different situation, are constructed by 

 Anthidium manicatum a . This gay insect does not exca- 

 vate holes for their reception, but places them in the 

 cavities of old trees, or of any other object that suits its 

 purpose. Sir Thomas Cullum discovered the nest of 

 one in the inside of the lock of a garden-gate, in which I 

 have also since twice found them. It should seem, how- 

 ever, that such situations would be too cold for the grubs 

 without a coating of some non-conducting substance. 

 The parent bee, therefore, after having constructed the 

 cells, laid an egg in each, and filled them with a store of 

 suitable food, plasters them with a covering of vermiform 

 masses, apparently composed of honey and pollen ; and 

 having done this, aware, long before Count Rumford's 

 experiments, what materials conduct heat most slowly, 

 she attacks the woolly leaves of Stachys lanata, Agro- 

 stemma coronaria, and similar plants, and with her man- 

 dibles industriously scrapes off the wool, which with her 

 fore legs she rolls into a little ball and carries to her nest. 

 This wool she sticks upon the plaster that covers her 

 cells, and thus closely envelops them with a warm coat- 

 ing of down impervious to every change of temperature 5 . 



The bee last described may be said to exercise the 

 trade of a clothier. Another numerous family would be 



a Curtis Brit. Ent. t. 61. 



b Mon. Ap. Angl. i. 173. Apis. **. c. 2. a. From later observa- 

 tions I am inclined to think that these cells may possibly, as in the 

 case of the humble-bee, be in fact formed by the larva previously to 

 becoming a pupa, after having eaten the provision of pollen and ho- 

 ney with which the parent bee had surrounded it. The vermicular 

 shape, however, of the masses with which the cases are surrounded, 

 does not seem easily reconcileable with this supposition, unless they 

 are considered as the excrement of the larva. 



2*2 



