70 
BRITISH BEETLES. 
black, uniformly coloured insects, but P. c upreus and 
one or two others are brilliantly metallic ; they are 
very variable in size ; P. madidus is one of the 
commonest of all our insects, and may be met with in 
almost every garden or back -yard ; P. picivianus 
(Plate II., Fig. 3) is found in cracks of tanks, and 
under stones, near water. 
In the Bipalmati the males have the first two 
joints of the anterior tarsi dilated (or, in some in- 
stances, quite simple), and the soles almost always 
clothed with squama; ; in Tachypus alone they are 
pilose ; the division may be naturally subdivided into 
two tribes, the Bembidiina and the Trechina. 
The Bembidiina, which have, until comparatively 
recently, been usually regarded as the last of the 
Geodephaga, may readily be known by the ond joint 
of their palpi being acute, needle-shaped, and ex- 
tremely small, the preceding joint being large and 
club-shaped. The two first joints of the front tarsi 
are sometimes widened in the male ; but often the 
front tarsi are simple in both sexes. 
The members of this tribe are all very small, the 
largest not being a quarter of an inch in length, and 
one of them, Tacky* bistriatus, three-quarters of a line 
long, is the smallest British Geodephagous insect. 
They occur generally in very wet places, such as the 
sea-shore, banks of ponds, rivers and streams ; in reedy 
marshes, and under stones in bogs, &c. Their prevailing 
colour is brassy-green or bronze, many being black ; 
and there is a tendency in the majority to assume a 
pattern of four white or yellow spots on the wing- 
cases. Several species emit an acrid, nasty-smelling, 
milky fluid, on being captured. 
