3o8 INSECT LIFE xxn 



terpretation of the facts does not involve this. 

 Tlie conclusion appears to be that she retains a 

 tenacious impression of the spot occupied by the 

 nest, returning there with an indefatigable obstinacy 

 when the nest is gone. But of the nest itself she 

 has a very vague notion — does not recognise her own 

 masonry kneaded with her own saliva, nor the honey 

 paste she had collected. Vainly does she visit her 

 work, the cell ; she abandons it, not acknowledging 

 it any more, since the place where lies the pebble is 

 no longer the same. 



We must own that insect memory is a strange 

 one, so lucid in general knowledge of locality, 

 so limited as to its home. I should be disposed to 

 name it topographical instinct ; the creature knows 

 the localities, but not the dear nest — the dwelling. 

 The Bembex led us to a like conclusion. The nest 

 being laid open, she cared nothing for the family — for 

 the larva writhing distressfully in the sun unrecog- 

 nised. What they do recognise, what they seek, and 

 find with marvellous precision, is the place where no 

 longer exists anything of the entrance door — not 

 even a threshold. 



If any doubt remain as to the powerlessness of 

 Chalicodoma muraria to know her nest except by the 

 place which the pebble occupies on the ground, this 

 may set it at rest. I substituted a nest of one mason 

 bee for that of another, as alike as might be, both in 

 masonry and storage. Of course this exchange and 

 those of which I shall speak later were made during 

 the absence of the owner. In the nest not hers, but 

 placed where her own had been, she established 

 herself without hesitation. If she had been building, 



