102 [October, 



I saw none of those I had lately released. Had they not known how 

 to regain their home ? Were they on a hunting expedition, or had 

 they really concealed themselves in their galleries in order to calm the 

 emotions of such a trial ? I do not know. The next day I made 

 another visit, and this time I had the satisfaction of finding five Cer- 

 qerides, with a double white spot on the thorax, as actively at work as 

 if nothing extraordinary had happened. A distance of at least three 

 kilometres, the town with its houses, its roofs, its smoky chimneys — 

 things all new to these free countrymen, had been no obstacles to 

 their return to their nest. 



Taken out of its flock and transported to enormous distances the 

 pigeon promptly returns to the dove-cot. If we draw a proportion 

 between the length of the passage and the bulk of the creature, how 

 much the Cerceris transported to a distance of three kilometres and 

 returning to its burrow will be superior to the pigeon ! The bulk of 

 the insect is not a cubic centimetre, and that of the pigeon amounts to 

 quite a cubic decimetre, if it do not exceed it. The bird, a thousand 

 times larger than the hymenopteron, should , in order to rival it, regain 

 the dove-cot from a distance of 3000 kilometres, three times the length 

 of France from north to south. I do not know that a traveller-pigeon 

 has ever accomplished such a feat. But power of wing, and still less 

 clearness of instinct, are not qualities to be measured by the metre. 

 The relations of bulk cannot here be taken into consideration, and we 

 can only see in the insect a worthy rival of the bird without deciding 

 which has the advantage. 



To return to the dove-cot and the burrow. "When the pigeon and 

 the Cerceris are artificially removed from home by man and trans- 

 ported to great distances into regions hitherto unvisited by them, are 

 they guided by remembrance ? Can memory serve them for a compass 

 when, arrived at a certain elevation, they may recover the lost point 

 and start forth, with all their power of flight, on the side of the 

 horizon where their nests are to be found ? Is it memory which traces 

 their route in the air to traverse regions they see for the first time ? 

 Evidently not ; there can be no remembrance of the unknown. The 

 hymenopteron and the bird know not the places in which they find 

 themselves ; nothing can have informed them of the general direction 

 in which their displacement can have been effected, for it was in the 

 darkness of a close basket or of a box that the journey was made. 

 Locality, orientation, are unknown to them ; nevertheless, they are 

 found again. They have, then, for guide more than simple remem- 

 brance ; they have a special faculty, a kind of topographical sense, of 

 which it is impossible for us to have any idea, not having anything 

 analogous to it. 



