Sph^ridiad^.- 
•INSECTS.' 
phoroid group are often covered, and all but incon- 
spicuous with mud. The larvae are carnivorous, while 
the perfect insects eat plants. 
The Elophorus aquaticus covers itself with mud, so 
that when feeding at the bottom of a pool it can 
scarcely he distinguished by the ferocious aquatic 
insects, Dytiscida and Water Bugs, which would prey 
on it more often than they do, were it not so curiously 
at times hid from their search. 
The Limnius ceneus has been observed by Kirby. 
It is found in rivulets under stones, at times covers its 
elytra with a coating of sand, which becomes as hard 
nearly as stone. 
Fig. 83. 
Hydrous piceus (male ) — a the mandible , b antenna. 
The largest species of the family belong to the first 
tribe. One of these. Hydrous piceMs (fig. 83), is the 
largest water-beetle found in this country. These 
insects are very bad swimmers, notwithstanding the 
oar-like structure of their four hind legs. Their food 
is principally vegetable substances, although in cap- 
tivity they eat greedily the larvae of other aquatic insects 
and aquatic molluscs. They breathe by bringing their 
heads to the surface. The insects often leave the 
water, especially at night. The females construct 
Fig. 84. 
a cocoon, which they attach to water plants on the 
surface of the water. The cocoon is of a short pear- 
shape, and of a paper-like substance. The eggs are 
regularly arranged within, and are wrapped up in a 
cottony substance. They are hatched in six weeks. 
Lamellicornia. 213 
The larvse are very voracious. Unlike the perfect 
insects, they only feed on vegetable life. 
The female of Spercheus also makes a cocoon, which 
she carries attached to her abdomen. Every nine or 
ten days it is destroyed by the exit of the young 
larvae. M. Cussac found that a female in six broods 
could rear at least four hundred larvae. Fig. 84 
represents Spercheus emarginatus. 
Family— SPH.aiRlDIAD^. 
The family SphaERIDIAD.(E are so called from the 
typical genus Sphceridiuin. They are a group of 
roundish insects, found in the dung of animals, such as 
horses and cows. Their strongly-spined tibiae enable 
them to enter the delicious mess, which to them is a 
true feast. There are twenty-two British species 
arranged in five genera, namely, Cyclonotum, Spliceri- 
dium, Cercyon, Megasternum, and Cryptopleurum. 
The species of the latter genera are ver}'’ obscure 
indeed. 
Lacordaire divides the Palpicorns into five tribes — 
I. Tlie second joint of the four posterior tarsi long, the first 
very short. 
These same tarsi oar-like ; a sternal spine, HydropMlides. 
II. The tarsi not oar-like , no sternal spine, Hydrdbiides. 
III. The first four joints of these tarsi short, equal, Spercheides. 
IV. The four first joints short, the first indistinct, Helophorides. 
V. The first joint elongated, . . . Spliaridiides. 
Group— LAMELLICORNIA. 
The group of Lamellicorn Beetles is a very large 
and well-marked one, which derives its name from 
the terminal joints of the antennae forming a lamel- 
lated mass. If any one examines a specimen of the 
Common Cockchafer alive, particularly if the speci- 
men be a male, the characteristic mark of this family 
will be seen in the terminal plates of the antennae. 
In the Stag Beetles, which, however, belong to this 
great group, the terminal plates of the antennae are 
only serrated (Plate 1, figs. 9, 10). The legs are 
strong, the fore tibiae, particnlaily in the female, being 
toothed. The males in many of the species are armed 
on the head and thorax with horns, or have the jaws 
much developed. Excepting among the Longicorn 
beetles, larger and more bulky species are nowhere else 
to be found among the Coleoptera. Their larvae are 
thick and fleshy, and have the end of the body curved 
towards the breast, so that the grub has to lie on its 
side. These beetles live on vegetable substances exclu- 
sively, as will be mentioned more particularly under 
each family. In tropical climates we have the gigantic 
Goliath beetles, and the even larger Elephant and 
Hercules beetles. The Sacred beetles and dung-rolling 
tribes belong to this group, the Chafers so destructive 
to leaves and roots. 
Family — GEOTRUPIDAE {Dung Beetles). 
We now come to the family Geotrupid^e. From 
the observations of Mr. Arthur Adams, that naturalist, 
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