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if they had not already done; and it is very permissible to suppose 
that the eight absent ones were delayed on their way by hunting their 
prey, or had already retired to the depths of their galleries. Thus, 
transferred to a distance of two kilometres in a direction and by a 
means of which they could have had no knowledge at the bottom of 
their paper prison, my Cercerides had returned, in part at least, to 
their home. 
I do not know to what distance the Cercerides extend their hunting, 
and it may be that within a radius of two kilometres the country is 
more or less known to them. If they had not been carried far enough 
at the place to which I had transported them, they would then regain 
their home by their acquired acquaintance with the locality ; so the 
experiment had to be repeated, with a greater intervening distance, 
and a place of departure that could not be suspected of being known 
to the hymenopteron. 
At the same group of burrows from which I had drawn in the 
morning I then took nine female Cerceris, of which three had been 
subjected to the preceding experiment, and the transportation was 
effected in the darkness of a box, each insect being shut up in a cornet 
of paper. The point of departure selected was the neighbouring 
town of Carpen tras, distant about three kilometres from the burrows. 
I determined to release my insects not in the midst of the fields, as at 
the first time, but in the public street, in the centre of a populous 
quarter, to which the Cercerides, with their rustic habits, had certainly 
never penetrated. As the day was already advanced, I deferred the 
experiment, and my captives passed the night in their cellular prisons. 
The next morning, about eight o’clock, I marked them on the 
thorax with a double white spot, in order to distinguish them from the 
former captures, which bore only a single spot, and I set them at 
libertv, one after the other, in the middle of the street. Each released 
Cerceris rose up vertically between the two rows of houses, as if to 
disengage itself as quickly as possible from the defile of the street 
and obtain the wide horizon ; then, clearing the roofs, it launched out 
immediately with a hasty flight towards the south. It was from the 
south that I had brought them into the town ; it was at the south they 
would find their burrows. JN'ine times, with my nine prisoners set 
free one after the other, I had this striking example of an insect, 
carried into a district entirely new to it, not hesitating as to the di- 
rection it should take to return to its nest. 
Some hours later I was at the burrows. I saw several Cerceris of 
the first lot, recognisable by the single white spot on the thorax, but 
