154 ‘ZOOLOGY. 
Fam. 2. Gyrinidw. Tere the antenne are short, and of eleven articu- 
lations, the eye of each side is divided into two parts by the sides of the 
head, and the posterior and middle feet are flat and very short. They swim 
in circles upon the surface of the water, sometimes in great numbers, and 
when disturbed they dive with great facility. Like the preceding family, 
they are sometimes active in winter; and one species, according to West- 
wood, has been found upon Mount Etna in the region of perpetual snow. 
The second sub-tribe Rypophaga (or cleansers) have the antennee clavate, 
or thickening towards the apex, two labial and two maxillary palpi, the 
galea represented by the exterior maxillary lobe, which is generally dilated, 
and sometimes jointed, seldom palpiform. There are three stirpes, Phdl- 
hydria, Necrophaga, and Brachelytra. 
The Philhydria partake of the aquatic habits of the Hydradephein, 
living along its moist margins. They have the body short, and convex 
above, the aieea en covered by the elytra, the hind feet ee for swim- 
ming or walking, the mandibles small, the maxillary palpi with four 
articulations, and the outer lobe generally articulated. The Phahydria 
contain the six families: 1, Heteroceride ; 2, Parnide ; 3, Helophoride ; 
4, Hydrophilide ; 5, Spheridude ; 6, Agathidude. The first are the 
Acanthopoda, the second the Macrodactyla, and the third, fourth, and fifth, 
the Palpicornea of Latreille. | 
In the fourth family, Zydrophilide, the body is ovate or hemispherical, 
and adapted for swimming or walking upon subaquatic objects. The pro- 
thorax is narrowed anteriorly, and the feet are compressed. They are 
generally of dull tints, they prefer stagnant waters, and some are found in 
those that are brackish. Some of those which swim have the trasi of the 
four hinder feet fringed with long hairs. Hydrophilus (pl. 81, fig. 18) is a 
genus of large Coleoptera, with the sternum ending posteriorly with a long 
spine, the antennee of nine articulations, and shorter than the maxillary 
palpi. In swimming, the feet are moved alternately, giving a less rapid 
motion than in the predaceous families; and being vegetable feeders in 
their imago state, they have no need of great locomotive powers. The 
female has a posterior pair of organs for secreting a cocoon to contain the 
eggs. This is nearly an inch in diameter, and is composed of fine white 
suk interiorly, with a gummy coating which hardens, and is impervious to the 
water. It is affixed to floating aquatic plants. It is formed in about half 
an hour, and the extremity of the abdomen serves as a mould upon which 
to form it. The eggs, to the number of fifty or sixty, are inclosed in a 
regular upright position, and the young escape below where the aperture is 
very slightly closed. 
The second stirps, the Vecrophaga of Latreille, have the body depressed, 
the elytra often abbreviated, the apex of the antenne thickened, the man- 
‘dibles generally prominent, the maxillze with a double membranous extension, 
the outer lobe slender, rarely articulate, the maxillary palpi with three articu- 
lations, or with the basal articulation minute, and the feet ambulatory. These 
insects feed upon, and thus remove dead carcases; some remove decaying 
fungi in the same manner, and some feed upon the exuding juices of 
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