Economy of Energy 



helplessly In space, so the partition with its 

 serving-hatch takes precedence of the victuals. 

 This method is a little more expensive than 

 the other, first in materials, because of the 

 diameter of the reed, and secondly in time, if 

 only because of the dog-hole, a delicate piece 

 of mortar-work which is too soft at first and 

 cannot be used until it has dried and become 

 harder. Therefore the Osmia, who is sparing 

 of her time and strength, accepts medium- 

 sized reeds only when there are no small ones 

 available. 



The large tubes she will use only in grave 

 emergencies and I am unable to state exactly 

 what these exceptional circumstances are. 

 Perhaps she decides to make use of those 

 roomy dwellings when the eggs have to be 

 laid at once and there is no other shelter in 

 the neighbourhood. While my cylinder-hives 

 gave me plenty of well-filled reeds of the first 

 and second class, they provided me with but 

 half-a-dozen at most of the third, notwith- 

 standing my precaution to furnish the appa- 

 ratus with a varied assortment. 



The Osmia's repugnance to big cylinders 

 is quite justified. The work in fact is longer 

 and more costly when the tubes are wide. 



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