168 
BRITISH BEETLES. 
the perfect insect (and especially the female) boing 
frequently to be seen lurking at the mouth of the 
burrow. 
The structure of the larva, the insertion and 
different cavities of the antenna), absence of a lubrum, 
and more closely fitting prothorax, accompanied by 
the lesser development of saltatorial power, distinguish 
this family from tho next, to which in many respects 
it is closely allied. 
Tho Elaterid/E have long antennae, which are 
either serrated, pectinated, or filiform, inserted im- 
mediately in front of the eyes, and (except in tho first 
sub-family) not received into prosternal grooves iu 
repose ; the eyes large and round ; the head (except 
in Campylus ) sunk in the thorax, with tho mouth 
very rarely on the lower side ; the labrum always 
distinct ; the mandibles normally short and somewhat 
semicircular, often bifid at tho apex; tho apical joint 
of the palpi more or less securiform (except as above) ; 
the thorax produced into spines at tho hinder angles, 
and sloped at tho baso towards the elytra, which are 
also sloped forwards ; tho scutellum mostly situated 
in a depression ; the prosternum usually produced iuto 
a chin-piece in front, and always with a dagger-like 
elongation behind, which moves very freely in the 
inesosternal cavity ; and the tarsi often furnished with 
lamellae beneath. 
They are nearly always of narrow, elongate, 
cylindrical shape, though sometimes flattened ; and 
are conspicuous for their power of jumjeiug when 
placed ou the back, from which their common names 
of “ Skipjacks/” or “ Click-beetles,” are derived. 
An Elater, before jumping, arches its body strongly. 
