136 
INSECTS. 
and is more or less artificial in its character. Most of the species included in the 
group feed upon decaying animal or vegetable matter, hence the name Necrophaga. 
The antennas exhibit in general a tendency to be thickened towards the tip, and in 
many cases the last three joints form a distinct club; but in some of the families 
antennae of quite another shape are to be found. Though usually five-jointed, the 
tarsi display in the number of their joints almost every variation met with in the 
Coleoptera. 
The family of Paussidce includes probably less than two hundred known 
species, the majority of which have been discovered in the tropics of Asia and 
Africa, though one species ( Paussus favieri) occurs in the south-west of Europe. 
They are mostly reddish brown insects, of rather small size, oblong form, and in 
general appearance little attractive, were it not for the extraordinary shapes of 
their antennas. These organs are generally very broad and flat, in some species 
resembling a paper-knife in shape; the number of joints varies from ten to two, 
and the last joint frequently has a bulbous or discoidal form. So far as at present 
known, all the species live in ants’ nests, and, unless sought for in these situations, 
they are rarely seen except at night when they occasionally fly into rooms, attracted 
by the light from the lamps. 
The tiny beetles belonging to the Pselapkidce resemble the Paussidce in exhibit¬ 
ing certain anomalies in their structure, and their lives are passed in similar obscure 
situations. But while the Paussidce may possibly be related to the Cktrabidce, the 
very short elytra of the Pselap>hidce, and the entirely horny nature of the dorsal 
plates of the abdomen seem to indicate an affinity with the Staphylinidce. In 
other points of structure, however, these two families are different. In the 
Pselapkidce the lobes of the maxillae are soft and membranous; and the abdomen, 
which in one group (the Clavigerince ) is composed of five segments, with the basal 
rings fused together, is quite incapable of the movements so characteristic of the 
rove-beetles. The joints of the antennae vary in number from eleven to six, 
or even two, and are in most cases clubbed at the end. While in one division 
of the family the palpi are usually composed of three or four joints, and are 
long and conspicuous, in the other they are one-jointed and scarcely visible. 
The tarsi are three-jointed, the first and second joints often very short, while 
the third is long and in many cases bears only a single claw. The Pselapkidai 
are distributed throughout most parts of the world. They are to be found 
under stones, moss, dead leaves, and other vegetable refuse, as well as under 
the bark of trees, and in damp marshy situations; but the most interesting 
species are those which live in ants’ nests. They are all of small size. The genus 
Claviger, comprising about eighteen European and one or two Asiatic species, has 
six-jointed antennae, and is further remarkable for the fact that the long cylindrical 
head is entirely devoid of eyes. The best known species, C. testaceus, is in 
Britain met with chiefly in the nests of the common yellow ant (Lasius Jlavus), 
though on the Continent it is found also in the nests of other species. It is 
about a tenth of an inch long, yellowish brown in colour, wingless, with the 
elytra fused together, and with a deej:> impression on the base of the abdomen. 
The relation between the ants and their guests is of a most interesting character. 
Whenever an ant meets one of these guests in a gallery of the nest, it gently 
