106 
BRITISH BEETLES. 
Their maxillary palpi are more or less elongate, with 
the apical joint subulate or pointed and very small ; 
the labrum and ligula both bilobed (the apex of the 
latter being tridentate in Scopaeus), the apical joint 
of the labial palpi small and pointed, and the para- 
glossae linear and ciliated on the inner side. The 
mandibles are slender, sharp, and long ; the head 
either attached to the thorax by a slender neck, or 
distinctly pedunculated ; and the tarsi, which are all 
five-jointed, have the fourth joint simple, except in 
Paederus and Sunius, where it is bilobed. 
The species of Pxderus are all very brightly co- 
loured ; — red, bluish- or greenish-black, and yellow, in 
sudden contrast, being their usual tints ; and they are 
especially noteworthy for the very deep notching of 
the penultimate segment of the abdomen beneath in 
the male. 
P. caligatus (Plate IV., Pig. 6), hitherto exceedingly 
rare, has recently been found in profusion in very wet 
mossy places on Wimbledon Common. 
Lathrobium comprises certain elongate, flattish, 
marsh-loving insects (some, also, occurring in sand- 
pits), of which the most gaily coloured have merely 
half the elytra stained with red, and which afford no 
subject of remark, except that good characters for 
their specific discrimination are to be found in the 
notching, &c., of the under surface of the penultimate 
abdominal segment in the males. 
Achenium, found in the cracks of mud-banks and 
under stones, has a wide, but very thin body, emi- 
nently adapted to its habitat ; and a departure from 
the normal form of antenna, in this family, is afforded 
by the light-footed Cryptobium fracticorne (in which 
