82 
BRITISH BEETLES. 
and inserted in its middle (Plate III., Fig. 6 1 ’)- The 
anterior legs are long and slender, and the interme- 
diate and hinder pair close together, removed from the 
front, and extremely compressed, with the femora, 
tibise, and basal joint of the tarsi very broad and 
triangular (Plate III., Fig. 6 C ). The Chjrini, com- 
monly known as “ water-fleas,” “ whirlwigs,” or 
“ whirligigs,” may be seen in fine weather forming end- 
less “ figures of 8 ” on the surface of both running 
and still waters. They are small, metallic, shining 
black, elongate beetles, exceedingly wary and quick 
in their movements, and with a power of exuding a 
very nasty-smelling acrid milky fluid, from nearly all 
parts of the body apparently, when handled. This 
fluid is analogous to that secreted by some Geode- 
phaga, which it resembles in evil odour. The female 
lays small cylindrical eggs, end to end, in level 
rows, on water-plants, the larvae proceeding from 
which are very peculiar, being narrow and flattened, 
with a long slender filament rising out of each side of 
all the segments except those bearing the legs. These 
filaments act as air-conductors, and give the animal 
the look of a Centipede. When full-grown, it ascends 
water-plants, and forms a small oval cocoon, of a sub- 
stance like grey paper, in which it assumes the pupa 
state. 
Gyrinus bicolor (Plate III., Fig. 6), the narrowest 
and most elongate of our “ whirlwigs,” is found plen- 
tifully in brackish water at Southend, and elsewhere 
on the coast. 
Orectochilus villosus, one of this family, differs from 
the others in being hairy : it is supposed to be less 
gregarious than the true Gyrini , though instances 
