e
behind, and advancing with it. The wasp seemed much disturbed by the
presence of the tiny flies, and twice left its prey to fly up towards
them, but they darted away with it. As soon as the wasp returned to
the spider, there they were hovering over and following it again. At
last, unable to drive away its small tormentors, the wasp reached its
burrow and took down the spider, and the two flies stationed
themselves one on each side the entrance, and would, doubtless, when
the wasp went away to seek another victim, descend and lay their own
eggs in the nest.

[Illustration: WASPS' NEST.]

[Illustration: THE SAND-WASP.]

The variety of wasps, as of all other insects, was very great around
Santo Domingo. Many made papery nests, hanging from the undersides of
large leaves. Others hung their open cells underneath verandahs and
eaves of houses. One large black one was particularly abundant about
houses, and many people got stung by them. They also built their
pendent nests in the orange and lime trees, and it is not always safe
to gather the fruit. Fortunately they are heavy flyers, and can often
be struck down or evaded in their attacks. They do good where there
are gardens, as they feed their young on caterpillars, and are
continually hunting for them. Another species, banded brown and yellow
(_Polistes carnifex_), has similar habits but is not so common.
Bates, in his account of the habits of the sand-wasps at Santarem, on
the Amazon, gives an interesting account of the way in which they took
a few turns in the air around the hole they had made in the sand
before leaving to seek for flies in the forest, apparently to mark
well the position of the burrow, so that on their return they might
find it without difficulty. He remarks that this precaution would be
said to be instinctive, but that the instinct is no mysterious and
unintelligible agent, but a mental process in each individual
differing from the same in man only by its unerring certainty. I had
an opportunity of confirming his account of the proceedings 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
he