236 THE WONDERS OF INSTINCT 



laying and the fullness of her vigor; later, when she is 

 perhaps already at the end of her strength, she bestows 

 what remains of her maternal solicitude upon the weaker 

 sex, the less-gifted, almost negligible male sex. There 

 are, however, other species where this law becomes abso- 

 lute, constant and regular. 



In order to go more deeply into this curious question 

 I installed some hives of a new kind on the sunniest walls 

 of my enclosure. They consisted of stumps of the great 

 reed of the south, open at one end, closed at the other 

 by the natural knot and gathered into a sort of enormous 

 pan-pipe, such as Polyphemus might have employed. 

 The invitation was accepted : Osmise came in fairly large 

 numbers, to benefit by the queer installation. 



Three Osmise especially (0. tricornis, Latr., O cornuta, 

 Latr., O. Latreillii, Spin.) gave me splendid results, with 

 reed-stumps arranged either against the wall of my gar- 

 den, as I have just said, or near their customary abode, 

 the huge nests of the Mason-bee of the Sheds. One of 

 them, the Three-horned Osmia, did better still : as I have 

 described, she built her nests in my study, as plentifully 

 as I could wish. 



We will consult this last, who has furnished me with 

 documents beyond my fondest hopes, and begin by ask- 

 ing her of how many eggs her average laying consists. 

 Of the whole heap of colonized tubes in my study, or else 

 out of doors, in the hurdle-reeds and the pan-pipe appli- 

 ances, the best-filled contains fifteen cells, with a free 

 space above the series, a space showing that the laying 

 is ended, for, if the mother had any more eggs available, 



