umbers of either ants or
spiders are eaten by birds, but in tropical America there are enormous
numbers of humming-birds feeding almost exclusively upon spiders, and
there the protective advantage of looking like ants must be of great
importance to the smaller species.

Belt considers that the advantages gained by ant-mimicking Central
American spiders lies entirely on the side of protection. In relation
to this subject he says: "Ant-like spiders have been noticed
throughout tropical America and also in Africa. The use that the
deceptive resemblance is to them has been explained to be the facility
it affords them for approaching ants on which they prey. I am
convinced that this explanation is incorrect, so far as the Central
American species are concerned. Ants, and especially the stinging
species are, so far as my experience goes, not preyed upon by any
other insects. No disguise need be adopted to approach them, as they
are so bold that they are more likely to attack a spider than a spider
them. Neither have they wings to escape by flying, and generally go in
large bodies easily found and approached. The use is, I doubt not, the
protection the disguise affords against small insectivorous birds. I
have found the crops of some humming-birds full of small, soft-bodied
spiders, and many other birds feed on them. Stinging-ants, like bees
and wasps, are closely resembled by a host of other insects; indeed,
whenever I found any insect provided with special means of defence I
looked for imitative forms, and was never disappointed in finding
them."

The ant-like species are probably protected by their appearance from
the attacks of many of the larger spiders. We have kept great numbers
of Attidae in captivity, and, although they devoured flies, gnats,
larvae, and other spiders, they would never touch ants. Among spiders,
however, as among birds, we find that certain groups subsist almost
entirely upon ants.

The class of spiders whose mimicry protects them from their enemies,
whether they are birds or other spiders, probably includes at least
two of our own ant-like species, Synageles picata and Synemosyna
formica, which, in confinement, are always hungry for gnats, but will
not touch ants, even of small size.

The existence of a class of spiders which mimic the particular species
of ants upon which they prey is not to be questioned, but it is
doubtful whether the benefit to the spider is increased facility in
capturing