VARIATION. 



119 



cell the loose sand rolls down and skilfully 

 covers the entrance as with a curtain. 

 Through this curtain the mother readily 

 pushes her head on returning with food, 

 which at first consists of small insects, no 

 larger than the larva can wholly consume 

 before they become high ; then as the larva 

 grows, larger insects are brought to meet 

 its increased appetite. The loose sand 

 covers the entrance of the burrow so skil- 

 fully that the human eye cannot detect the 

 spot, although the mother has just left ; 

 but she has no difficulty in finding the en- 

 trance on her return with food. After a 

 day's absence she will return to the entrance 

 with the utmost precision, and push her head 

 at once through the curtain. So wonderful 

 has Monsieur Fabre found, by various experi- 

 ments, the homing faculty of these hymenop- 

 tera, that he ascribes to them a sense of 

 which man knows nothing. 



Again, the Mason-bee does not dig holes, 

 but constructs on detached stones or under 

 eaves cells of calcareous dust made into mor- 

 tar with saliva, and feeds its larva on honey 

 and pollen mixed into a paste, with its man- 

 dible for a spoon. With this paste the cell 

 is stored ; an egg is then laid on the top, and 

 the cell sealed up. 



