Mental Process in Wasps 105 
agent, but a mental process in each individual differing 
from the same in man only by its unerring certainty.1 I 
had an opportunity of confirming his account of the pro- 
ceedings of wasps when quitting a locality to which they 
wished to return, in all but their unerring certainty. I 
could not help noting how similar they were to the way in 
which a man would act who wished to return to some spot 
not easily found out, and with which he was not previously 
acquainted. A specimen of the Polistes carnifex was hunting 
about for caterpillars in my garden. I found one about 
an inch long, and held it out towards the wasp on the point 
of a stick. The wasp seized the caterpillar immediately, 
and commenced biting it from head to tail, soon reducing 
. the soft body to a mass of pulp. Then rolling up about one- 
half of the pulp into a ball, it carried it off. Being at the 
time amidst a thick mass of a fine-leaved climbing plant, it 
proceeded, before flying away, to take note of the place 
where the other half was left. To do this, it hovered in 
front for a few seconds, then took small circles in front, then 
larger ones round the whole plant. I thought it had gone, 
but it returned again, and had another look at the opening 
in the dense foliage down which the other half of the cater- 
pillar lay. It then flew away, but must have left its burden 
- for distribution with its comrades at the nest, for it returned 
in less than two minutes, and making one circle around the 
bush, descended to the opening, alighted on a leaf, and ran 
inside. The green remnant of the caterpillar was lying on 
another leaf inside, but not connected with the one on which 
the wasp alighted, so that in running in it missed the object 
and soon got hopelessly lost in the thick foliage. Coming 
out, it took another circle, and pounced down on the same 
spot again, as soon as it came opposite to it. Three small 
seed-pods, which here grew close together, formed the marks 
that I had myself taken to note the place, and these the wasp 
seemed also to have taken as its guide, for it flew directly 
down to them, and ran inside; but the small leaf on which 
the fragment of caterpillar lay, not being directly connected 
with any on the outside, it again missed it, and again got 
far away from the object of its search. It then flew out 
again, and the same process was repeated again and again. 
1 Naturalist on the Amazon, p. 222. 
