THE OSMLE 245 



clings to it with a patience extremely difficult to exhaust. 

 It is here, in this little familiar corner, that she prefers 

 to settle her progeny. But then the apartments are few 

 in number and of all shapes and sizes. There are long 

 and short ones, spacious ones and narrow. Short of ex- 

 patriating herself, a Spartan course, she has to use them 

 all, from first to last, for she has no choice. Guided 

 by these considerations, I embarked on the experiments 

 which I will now describe. 



I have said how my study became a populous hive, in 

 which the Three-horned Osmia built her nests in the 

 various appliances which T had prepared for her. 

 Among these appliances, tubes, either of glass or reed, 

 predominated. There were tubes of all lengths and 

 widths. In the long tubes, entire or almost entire lay- 

 ings, with a series of females followed by a series of 

 males, were deposited. As I have already referred to 

 this result, I will not discuss it again. The short tubes 

 were sufficiently varied in length to lodge one or other 

 portion of the total laying. Basing my calculations on 

 the respective lengths of the cocoons of the two sexes, on 

 the thickness of the partitions and the final lid, I short- 

 ened some of these to the exact dimensions required for 

 two cocoons only, of different sexes. 



Well, these short tubes, whether of glass or reed, were 

 seized upon as eagerly as the long tubes. Moreover, they 

 yielded this splendid result: their contents, only a part 

 of the total laying, always began with female and ended 

 with male cocoons. This order was invariable; what 



