238 THE WONDERS OF INSTINCT 



The contents of these compartments are no less uneven 

 between one portion and another of the string. With- 

 out any exception known to me, the large cells, those 

 with which the series starts, have more abundant provi- 

 sions than the straitened cells with which the series ends. 

 The heap of honey and pollen in the first is twice or even 

 thrice as large as that in the second. In the last cells, 

 the most recent in date, the victuals are but a pinch of 

 pollen, so niggardly in amount that we wonder what 

 will become of the larva with that meager ration. 



One would think that the Osmia, when nearing the end 

 of the laying, attaches no importance to her last-born, to 

 whom she doles out space and food so sparingly. The 

 first-born receive the benefit of her early enthusiasm: 

 theirs is the well-spread table, theirs the spacious apart- 

 ments. The work has begun to pall by the time that the 

 last eggs are laid ; and the last-comers have to put up with 

 a scurvy portion of food and a tiny corner. 



The difference shows itself in another way after the 

 cocoons are spun. The large cells, those at the back, 

 receive the bulky cocoons ; the small ones, those in front, 

 have cocoons only half or a third as big. Before open- 

 ing them and ascertaining the sex of the Osmia inside, 

 let us wait for the transformation into the perfect insect, 

 which will take place towards the end of summer. If 

 impatience get the better of us, we can open them at the 

 end of July or in August. The insect is then in the 

 nymphal stage; and it is easy, under this form, to dis- 

 tinguish the two sexes by the length of the antennae, 

 which are larger in the males, and by the glassy pro- 



