Eypophaga. INSECTS. Bkachelytba, 
aa Prosteniiim Joined beliind with the metasternum. 
Posterior coxa furnished with plates partly covering 
the abdomen, .... Haliplides. 
Posterior cox® without plates, . . Peldbidea. 
11. Posterior coxa very large, widened in front. 
h Four anterior tarsi, furnished with only four joints, 
Hydroporides. 
hb All the tarsi furnished with five joints. 
The dilated joints in the males simple, with small 
cupules of equal size, . . Colymbetides. 
The dilated joints of males in the form of a great 
suborbicular palette, with small cupules of unequal 
size. 
They are all included by Mr. Waterhouse in the 
family Dytisddcs. He gives one hundred and eleven 
species as natives of the British islands. They are in 
the genera Dyiiscus, Acilius, Hydaiicus, Colymhetes, 
Tlyhius, Agabus, Noterus, Laccophilus, Hyphidrus, 
Hydroporus, Haliplus, Gnemidotus, and Pelohius. 
The Dyiiscus marginalis is a common species in 
this country, and is so named from the conspicuous 
yellow margin of the thorax. Water-beetles fly about 
at night, and frequently in moonlight nights dash them- 
selves against glass-windows, which they seem to mis- 
take for pools or streams. 
These water-insects are very carnivorous; their larvae 
are often very beautiful objects for the microscope. 
Family — G-YRINIDHS {Wfdrlwhigs). 
Who has not seen the Whirlwhigs gyrating on a 
pool or river — as if they did not touch the water? 
Some of the exotic species are of considerable size, 
Fig. 64. 
b 
a Hind leg of a species of Gyrinus. b Antenna. 
and are curiously formed. Others have pointed bodies 
and elytra. Their antennae and legs are very curious. 
Of the figures a is that of the hind leg; b that of the 
antenna. 
Sob-section — EYPOPHAGA ( Cleansers). 
The next sub-section of the Pentamera has been 
named Eypophaga, from the insects contained in it 
eatiiig putrid animal and vegetable matter, and in 
this way cleansing and clearing the ground. They 
have only four palpi, and the antennae in most of 
them are either gradually or suddenly clavate. In 
those which inhabit the water, the maxillary palpi are 
generally of considerable length ; and these organs, but 
for their having fewer joints, might be taken by the 
beginner for their antennae. In one large section of 
the group, the elytra are extremely short. This section 
is named Brachelytra. 
207 
Group— BRACHELYTRA. 
Generally longish beetles, with very short elytra, 
though a few of them are very short insects, and have 
elytra nearly covering the abdomen. 
There are at least two thousand species known of 
this extensive group of beetles. In fact, the greater 
portion of the above are European ; six hundred are 
recorded as British in Mr. Waterhouse’s Catalogue of 
British Coleoptera. It has been said that they are com- 
paratively rare in the intertropical regions; this seems, 
however, to arise from their not having been so much 
searched for as other groups. 
The following is the arrangement of the group in 
the monograph of Erichson, an arrangement which is 
generally adopted by all naturalists ; — 
I. Prothoracic stigmata visible, seldom covered by a horny 
free plate. 
Antenn® inserted at the inner margin of the eyes, 
Aleoclioridce. 
Two hundred and sixteen of these are British. 
Antenn® inserted below the side margins of the front, 
I'acliyporidx. 
Fifty-five are British. 
Antenn® inserted on the fore margin of the epistome, 
StaphylinidcB. 
Mr. Waterhouse divides this, as Kraatz does, into 
Quediid® and Staphylinid® — with one hundred 
and six British species. 
II. Prothoracic stigmata concealed by the epimera of the 
prothorax. 
A. Posterior cox® conical. 
a A membranous space between the fore-cox®, Pcederidce. 
Xantholinid® and P®derid® have fifty-seven recorded 
British species. 
aa Prothorax quite horny below. 
Antenn® inserted below the side margins of the 
front, PinophilidcB. 
Antenn® inserted on the front, . . . Stenidce. 
There are fifty British species. 
B. Posterior cox® transverse 
6 The anterior cox® globular, not prominent, Piestidce. 
Only one British species. Some of the exotic species 
are fine and large. 
hb The anterior cox® conical, prominent, 
c No ocelli. 
Abdomen seven-jointed, . . . Oxytelidce. 
There are forty-nine British species. 
Abdomen six-jointed, . . . Phlceockaridce. 
cc Front with two ocelli, .... Omalidce. 
There are forty-three British Omalid®. 
bhb Anterior cox® suh-cylindrical, transverse, Proteinida, 
There are nine British species. 
Of the little pretty Micropeplid®, with their curiously- 
pitted elytra, there are four British species. 
We here figure from Erichson’s work the Scy- 
talinus serpentinus, Tanygnathus terminalis, and the 
very curious Megalops cephalotes (figs. 65, 66 and 67), 
which, with the other figures, show the great variety 
of form amongst the Brachelytra. 
In their perfect state Staphylinidae chiefly feed on 
decaying animal and vegetable substance. Many of 
the species which are found on flowers or in fungi 
seem to be carnivorous ; the former frequent the flowers 
on account of the small insects which they find there, 
while the latter feast on the grubs which abound in fungi. 
These insects are accordingly found in many different 
