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- 
cerides, 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 ilock 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 P 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. 
