284 INSECT LIFE 



XX 



air, quite unsheltered, the nest will undergo the heat 

 of summer suns which will turn every cell into an 

 oven ; then will come the autumn rains which will 

 slowly eat away the masonry, and then winter frosts 

 which will crumble what the rain may have respected. 

 However hard the cement may be, can it resist all 

 these attacks, and if it can, will not the larvae, shel- 

 tered by so thin a wall, suffer from over-heat in 

 summer and too keen cold in winter ? 



Without having gone through all these argu- 

 ments, the bee acts wisely. When all the cells are 

 completed she builds a thick cover over the whole 

 group, which, being of a material impermeable to 

 water and almost a non-conductor, is at once a 

 defence against heat and cold and damp. This 

 material is the usual mortar, made of earth and 

 saliva, only with no small stones in it. The bee lays 

 it on, — one pellet after another, one trowelful and 

 then a second, — till there is a layer a centimetre thick 

 over all the cells, which disappear entirely under it. 

 The nest is now a rude dome, about as big as half 

 an orange ; one would take it for a clod of mud, 

 half crushed by being flung against a stone where 

 it had dried. Nothing outside betrays its contents — 

 no suggestion of cells — none of labour. To the 

 ordinary eye it is only a chance splash of mud. 



This general cover dries as rapidly as do our 

 hydraulic cements, and the nest is almost as hard as a 

 stone. A knife with a strong blade is needed to cut 

 it. In its final shape the nest recalls in no degree 

 the original work ; one would suppose the elegant 

 turrets adorned with pebble work, and the final 

 dome, looking like a bit of mud, to be the work of 



