Bramble-bees and Others 



old nest remains in its natural state. With a 

 grater, however, I scrape the outside of an- 

 other nest so as to reduce the depth of the 

 cavities to some ten millimetres.^ This leaves 

 in each cell just room for one cocoon, sur- 

 mounted by the closing stopper. Of the four- 

 teen cavities in the nests, I leave two intact, 

 measuring fifteen millimetres^ in depth. 

 Nothing could be more striking than the re- 

 sult of this experiment, made in the first year 

 of my home rearing. The twelve cavities 

 whose depth had been reduced all received 

 males; the two cavities left untouched received 

 females. 



A year passes and I repeat the experiment 

 with a nest of fifteen cells; but this time all 

 the cells are reduced to the minimum depth 

 with the grater. Well, the fifteen cells, from 

 first to last, are occupied by males. It must 

 be quite understood that, in each case, all the 

 offspring belonged to one mother, marked 

 with her distinguishing spot and kept in sight 

 as long as her laying lasted. He would in- 

 deed be difficult to please who would not bow 

 before the results of these two experiments. 



^About two-fifths of an inch. — Translator's Note. 

 2.585 inch. — Translator's Note. 



172 



