DASYGASTRES MASON-BEES FINDING THE NEST 39 



resign my claims I must require you to go through the exertions 

 that will prove you to be really the lawful owner. 



Another experiment was made with forty specimens of Chali- 

 codoma pyrenaica, which were removed to a distance of four 

 kilometres and then liberated. About twenty of the individuals 

 had lieen somewhat injured by the processes of capturing, mark- 

 ing, and transferring, and proved unable to make a proper start. 

 The others went off well when released, and in forty minutes the 

 arrivals at the nest had already commenced. The next morning 

 he was able to ascertain that fifteen at least had found their way 

 back, and that it was probable that most of the uninjured bees 

 had reached home ; and this although, as Fabre believed, they 

 had never before seen the spot where he liberated them. 



These observations on the power of Chalicocloma to regain 

 its nest attracted the attention of Charles Darwin, who wrote to 

 M. Fabre, and suggested that further observations should be 

 made with the view of ascertaining by means of what sense these 

 bees were able to accomplish their return. For it must be borne 

 in mind that this bee is very different from the domestic bee, 

 inasmuch as it enjoys but a brief life in the winged state, and it 

 is therefore to be presumed that an individual has no knowledge 

 of such comparatively distant localities as those to which Fabre 

 transported it. Further observations made by the Frenchman 

 have unfortunately failed to throw any light on this point. 

 Darwin thought it might possibly be some sensitiveness to 

 magnetic conditions that enabled the bees to return home, 

 and suggested that they should be tested as to this. Fabre 

 accordingly made some minute magnets, and fixed one to each 

 bee previous to letting them loose for a return journey. This 

 had the effect of completely deranging the bees ; and it was there- 

 fore at first thought that the requisite clue was obtained. It 

 occurred to the experimenter, however, to try the plan of affixing 

 small pieces of straw to the bees instead of magnets, and on this 

 being done it was found that the little creatures were just as 

 much deranged by the straws as they were by the magnets : thus 

 it became evident that no good grounds exist for considering 

 that the bees are guided by magnetic influences. 



One of the species ^ of Chalicocloma observed by Fabre fixes 



1 The " Chalicodome des gahts " ov C. " des murailles " of the French writer ; in 

 some places he speaks of the species as being C. inuraria, in others as C. parietina. 



