76 
BRITISH BEETLES. 
horny, quadrate, with the paraglossae soldered to its 
sides ; the palpi are mostly thread-like ; the maxillae 
are fringed on the inner side ; the scutellum is either 
very small, or not visible : the basal joints of the front 
tarsi are widened in the males, and all the species have 
stout and large wings. 
Their larvae are also aquatic, and very predaceous ; 
they are mostly elongate, somewhat cylindrical, and 
tapering to the tail, and with a broad head armed with 
two strong, pointed jaws. They generally construct 
hollow cells in banks of ponds, &c., and turn into 
pupae underground, near their native element. 
Our species may be divided into four families, the 
Haliplidce, Pelobiidce, DytiscicUe, and Gyrinidce. 
Of these, the Haliplid2G form a good connecting 
link with the Bembidiina in the Geodephaga, their legs 
not being widened, and formed for swimming, as in 
the other Hydradephaga, but thin, slender, and adapted 
for walking ; indeed, the species — though of aquatic 
habits — swim but feebly, frequenting weeds, &c., and 
running readily, with an alternate motion of the legs. 
The basal joints of their front tarsi, also, are not 
dilated in the males, a character found in some of the 
Bembidiina, and very rare in the Hydradephaga, some 
members of which afford, perhaps, the greatest known 
development of this structure. Their head is not so 
sunk in the thorax as in the majority of their allies ; 
and, lastly, in the genus Ilaliplus, the apical joint of 
the palpi is very small and needle-pointed, as in 
Bembidium. 
Their antennae are ten-jointed, and the coxae of the 
hinder legs not enlarged in front, but produced behind 
into a semicircular flat plate, which in Haliplus covers 
