The Mason-bees 



means the laying of an egg when the probe 

 reaches the cell. Here is a cocoon of the 

 Mason-bee of the Pebbles with an egg side by 

 side with the Chalicodoma-grub. But what 

 a curious egg! Never have my eyes beheld 

 the like; and then is it really the egg of the 

 Leucospis? Great was my apprehension. 

 But I breathed again when I found, a couple 

 of weeks later, that the egg had become the 

 larva with which I was familiar. Those co- 

 coons with a single egg are as numerous as I 

 can wish; they exceed my wishes: my little 

 glass receptacles are too few to hold them. 



And here are others, more precious ones 

 still, with manifold layings. I find plenty 

 with two eggs; I find some with three or 

 four; the best-colonized offer me as many as 

 five. And, to crown my delight, the joy of 

 the seeker to whom success comes at the last 

 moment, when he is on the verge of despair, 

 here again, duly furnished with an egg, is a 

 sterile cocoon, that is to say, one containing 

 only a shrivelled and decaying larva. All my 

 suspicions are confirmed, down to the most 

 inconsequent : the egg housed with a mass of 

 putrefaction 



The nests of the Mason-bee of the Walls 

 306 



