58 INSECT ARCHITECTU 



made seems not to be very clearly understood. M 

 Latreille says, that after constructing her nest of the 

 down of quince leaves, she deposits her eggs, together 

 with a store of paste, formed of the pollen of flowers 

 for nourishing the grubs. Kirby and Spence, on the 

 other hand, tell us, that " the parent bee, after 

 having constructed her cells, laid an egg in each, and 

 filled them with a store of suitable food, plasters 

 them with a covering of vermiform masses, appa- 

 rently composed of honey and pollen; and having 

 done this, aware, long before Count Rumford"s expe- 

 riments, what materials conduct heat most slowly," 

 she collects the down from woolly plants, and " sticks 

 it upon the plaster that covers her cells, and thus 

 closely envelops them with a warm coating of down, 

 impervious to every change of temperature." " From 

 later observations," however, they are " inclined to 

 think that these cells may possibly, as in the case of 

 the humble-bee, be in fact formed by the larva pre- 

 viously to becoming a pupa, after having eaten the 

 provision of pollen and honey with which the parent 

 bee had surrounded it. The vermicular shape, how- 

 ever, of the masses with which the cases are sur- 

 rounded, does not seem easily reconcilesible with this 

 supposition, unless they are considered as the excre- 

 ment of the larva *.'' 



Whether or not this second explanation is the true 

 one, we have not the means of ascertaining; but we 

 are almost certain the first is incorrect, as it is con- 

 trary to the regular procedure of insects, to begin 

 with the interior part of any structure, and work out- 

 wards. We should imagine, then, that the down is 

 first spread out into the form required, and afterwards 

 plastered on the inside to keep it in form, when pro- 



* introduction to Entomology, vol. i., p. 435, 5th edit. 



