Economy of Energy 



the end cut by man's pruning-knife. If the 

 next partition be too near to give a chamber 

 of sufficient length, the Xylocopa destroys it, 

 which is easy work, not to be compared with 

 the labour of cutting an entrance through the 

 side. In this way, a spacious gallery, follow- 

 ing on the short vestibule made by the pru- 

 ning-knife, is obtained with the least possible 

 expenditure of energy. 



Guided by what was happening on the trel- 

 lises, I offered the black Bee the hospitality 

 of my reed-hives. From the very beginning, 

 the insect gladly welcomed my advances; each 

 spring, I see it inspect my rows of cylinders, 

 pick out the best ones and instal itself there. 

 Its work, reduced to a minimum by my inter- 

 vention, is limited to the partitions, the ma- 

 terials for which are obtained by scraping the 

 inner sides of the reed. 



As first-rate joiners, next to the Carpenter- 

 bees come the Lithurgi, of whom my district 

 possesses two species: L. corniitus, Fab., 

 and L. chrysurus, BoY. By what aber- 

 ration of nomenclature was the name of 

 Lithurgus, a worker in stone, given to insects 

 which work solely in wood? I have caught 

 the first, the stronger of the two, digging gal- 



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