254 TOLERATION OF PARASITES. 



removed the surface of the eavtii and the passage, 

 exposing the cell and the larva, the Bembex was quite 

 at a loss, and did not even recognize her own offspring. 

 It seems as if she knew tlie door, the nursery, and the 

 passage, but not her child. 



Another ingenious experiment of M. Fabre's was 

 made with a mason bee (Chalicodoma). This genus 

 constructs an earthen cell, through which at maturity 

 the young insect eats its way. M. Fabre found that if 

 he pasted a piece of paper ronnd the cell, the insect had 

 no difficulty in eating through it ; but if he enclosed the 

 cell in a paj^er case, so that there was a space even of 

 cnly a few lines betvveen the cell and the paper, in that 

 case the paper formed an effectual prison. The instinct 

 of the insect taught it to bite through one enclosure, 

 but it had not wit enough to do so a second time. 



One of the most striking instances of stujDidity 

 (may I say) is mentioned by M. Fabre, in the case of 

 one of his favourite bees, the Chalicodoma pjrenaica. 

 This species builds cells of masonry, which she fills with 

 honey as she goes on, raising the rim a little, then 

 making a few journeys for honey, then raising the rim 

 again, and so on until the cell is completed. She then 

 prepares a last load of mortar, brings it in her mandibles, 

 lays her egg, and immediately closes up the cell ; 

 having doubtless provided the mortar beforehand, lest 

 during her absence an enemy should destroy the egg 

 or any parasitic insect should gain admittance. This 

 being so, M. Fabre chose a cell which was all but 

 finished, and during the absence of the bee he broke 

 away part of the cell-covering. Again, in some half- 

 finished cells he broke away a little of the wall. In 

 all these cases the bee, as might be expected, repaired 



