The Mason-bees 



do. At any rate, the Chalicodoma's nest Is 

 more or less white because of the source of 

 its materials. When a red speck, a few milli- 

 metres wide, appears on this pale background, 

 it is a sure sign that a Stelis has been that 

 way. Open the cell that lies under the red 

 stain : we shall find the parasite's numerous 

 family established there. The rusty spot is 

 an infallible Indication that the dwelling has 

 been violated: at least, it is so In my neigh- 

 bourhood, where the soil is as I have de- 

 scribed. 



We see the Stelis, therefore, at first a rabid 

 miner, using her mandibles against the rock; 

 next a kneader of clay and a plasterer restor- 

 ing broken ceilings. Her trade does not seem 

 one of the least arduous. Now what did she 

 do before she took to parasitism? Judging 

 from her appearance, the transformists tell 

 us that she was an Anthidium, that is to say, 

 she used to gather the soft cotton-wool from 

 the dry stalks of the lanate plants and make 

 it into wallets, in which to heap up the 

 pollen-dust which she gleaned from the flow- 

 ers by means of a brush carried on her ab- 

 domen. Or else, springing from a genus 

 akin to the cotton-workers, she used to build 

 226 



