The Leucospes 



are the more regular In structure and are 

 easier to examine, because their base Is wide- 

 open once It Is separated from the supporting 

 pebble; and It was these which supplied me 

 with by far the greater part of my informa- 

 tion. Those of the Mason-bee of the Sheds 

 have to be chipped away with a hammer be- 

 fore one can inspect their cells, which are 

 heaped up anyhow; and they do not lend 

 themselves anything like so well to delicate 

 investigations, as they suffer both from the 

 shock and the Ill-treatment. 



And now the thing Is done : it remains cert- 

 ain that the Leucospis' laying is exposed to 

 very exceptional dangers. She can entrust the 

 egg to sterile cells, without provisions fit to 

 use; she can establish several In the same cell, 

 though this cell contains nourishment for one 

 only. Whether they proceed from a single 

 Individual returning several times, by Inad- 

 vertence, to the same place, or are the work 

 of different Individuals unaware of the pre- 

 vious borings, these multiple layings are very 

 frequent, almost as much so as the normal 

 layings. The largest which I have noticed 

 consisted of five eggs, but we have no au- 

 thority for looking upon this number as an 

 307 



