466 
INSECTA. 
eleven joints, the last six constituting' an almost cylindrical and 
slightly serrated club ; the second is short and not dilated. 
This tribe is composed of a single genus 
Heterocerus, Bose., Fab. 
These Insects are found in the sand or mud, along the borders of 
rivulets, marshes, &c., issuing from their holes when disturbed by the 
trampling of feet. The form of their tibiae enables them to turn up 
the earth, and conceal themselves in it ; their tarsi can be flexed upon 
the tibiae. There also reside their larvae, which were first discovered 
by M. Miger. 
H. marginatus. Fab.; H. Icevigatus, Ib. ; Panz., Faun,, Insect., 
Germ., XXIII, 12. A small, blackish, and silky Insect, with 
little yellowish or reddish spots, varying in form and number, 
and sometimes even wanting on the elytra. 
M. Gyllenhal observes that the tarsi really consist of five 
joints, the first of which is small and oblique. See Insect. Suec. 
I, p. 138. 
The second tribe, or that of the Macrodactyla, comprises Clavi- 
cornes with simple, narrow tibiae and long tarsi, all — one genus ex- 
ceiDted Georisstis^, well distinguished from every other tribe, by its 
antennae of nine joints, of which the three last form an almost solid 
club — composed of five distinct joints, the last of which is large, with 
two stout terminal hooks. The body is thick or convex. The tho- 
rax is less rounded, and most commonly terminates on both sides in 
acute angles. 
The principal type of this tribe is the genus 
Dryops, Oliv., 
Or that of Parnus, Fab., which is divided in the following manner : 
1. Those whose antennae, never much longer than the head, are 
composed of from ten to eleven joints, which, from the third, form an 
almost cylindrical or slightly fusiform club, arcuated, and somewhat 
serrated. 
PoTAMoPHiLus, Germ . — Parnus, Fah. 
The Potamophili, which, ignorant of the establishment of this sub- 
genus, we had named Hydera ■*, have their antennae exposed, and 
not received into particular cavities ; they are rather longer than the 
head ; the first joint is almost as long as the following ones taken to- 
gether, and the second short and globular. The palpi are salient, 
and the mouth is completely exposed as the praesternum does not 
project over it, a character in this tribe exclusively peculiar to this 
subgenus f . 
Regn. Anim., Ill, p. 268. 
t Parnus acuminatus, Fab.; Paez,, Faun. Insect. Germ., YI, 8; — Dryops pidjpeSf 
Oliv., Ill, 41, 1 , 2. 
