Economy of Energy- 

 shells prefer the reeds, which in all proba- 

 bility have never before been utilized by their 

 race? Most of them scorn the ancestral 

 dwelling and enthusiastically accept my reeds. 

 Some, it is true, take up their quarters in the 

 Snail-shell; but even among these a goodly 

 number refuse my new shells and return to 

 their birthplace, the old Snail-shell, in order 

 to utilize the family property, without much 

 labour, at the cost of a few repairs. Whence, 

 I ask, comes this general preference for the 

 cylinder, never used hitherto? The answer 

 can be only this: of two lodgings at her dis- 

 posal the Osmia selects the one that provides 

 a comfortable home at a minimum outlay. 

 She economizes her strength when restoring 

 an old nest; she economizes it when replacing 

 the Snail-shell by the reed. 



Can animal industry, like our own, obey the 

 law of economy, the sovran law that governs 

 our industrial machine even as it governs, 

 at least to all appearances, the sublime 

 machine of the universe? Let us go deeper 

 into the question and bring other workers into 

 evidence, those especially who, better-equipped 

 perhaps and at any rate better-fitted for hard 

 work, attack the difficulties of their trade 



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