The Mason-bees 



other's property, by continuing to store pro- 

 visions in a cupboard already full to overflow- 

 ing, by laying her egg in a cell in which the 

 real owner had already laid and lastly by 

 hurriedly closing an orifice that called for seri- 

 ous repairs. What better proof could be 

 wished of the irresistible propensity which the 

 insect obeys? 



Lastly, there are certain swift and consecu- 

 tive actions so closely Interlinked that the 

 performance of the second demands a previ- 

 ous repetition of the first, even when this ac- 

 tion has become useless. I have already 

 described how the Yellow-winged Sphex^ per- 

 sists In descending Into her burrow alone, 

 after depositing at Its edge the Cricket whom 

 I mahclously at once remove. Her re- 

 peated discomfitures do not make her abandon 

 the preliminary Inspection of the home, an 

 inspection which becomes quite useless when 

 renewed for the tenth or twentieth time. The 

 Mason-bee of the Walls shows us, under an- 

 other form, a similar repetition of an act 

 which is useless in itself, but which is the com- 

 pulsory preface to the act that follows. When 



^Cf. Insect Life: chaps, vi to ix. — Translator's Note. 

 ?0 



