The Mason-bees 



one knows, as I knew, how many times the 

 probe entered those cells. 



My perplexity only increases when, on the 

 return of summer, I witness for the second 

 time theXeucospis' repeated operations on the 

 same cells and for the second time find a sin- 

 gle larva in the compartments which have 

 been bored several times over. Shall I then 

 be forced to accept that the auger is able to 

 recognize the cells already containing an egg 

 and that it thenceforth refrains from laying 

 there? Must I admit an extraordinary sense 

 of touch in that bit of horse-hair, or even bet- 

 ter, a sort of divination which declares where 

 the egg lies without having to touch it? But 

 I am raving! There is certainly something 

 that escapes me; and the obscurity of the 

 problem is simply due to my Incomplete in- 

 formation. O patience, supreme virtue of 

 the observer, come to my aid once more ! I 

 must begin all over again for the third time. 



Until now, my investigations have been 

 made some time after the laying, at a period 

 when the larva is at least fairly developed. 

 Who knows? Something perhaps happens, 

 at the very commencement of infancy, that 

 may mislead me afterwards. I must apply to 

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