30 
In those of the second, the elytra are serrated, or armed with 
short spines, near their extremity. 
In the third, they are whole or entire. 
The late celebrated entomologist Mr. Thomas Yeates, of whose 
critical knowledge in, and just definition of the Linnæan prin- 
ciples, the Author has greatly availed himself, says, “ that very 
“ few insects of this genus in his time were found in Europe, and 
4 ‘ not a single specimen had been taken in England.” Collectors 
have since, however, been more fortunate, and four different 
species are figured, all of them for a certainty English. 
We are wholly unacquainted with their larvae and transforma- 
tions. 
GENUS XXIV. DYTISCUS. Tab. 32, 33, and 34. 
Linn. Syst. Nat. page 665. 
The antennae of this genus are either setaceous, or enlarged in 
size towards the point, with a perfoliated capitulum, or knob. 
The hind feet are hairy, which assist them in swimming, and 
are also furnished with claws. 
The Dytisci form two families ; the first are those with perfo- 
liated antennae; second, those whose antennae are setaceous. 
The under side of the fore feet of the male is hemispherical ; 
the elytra of the female are mostly furrowed. The male is some- 
thing like the Dermestides, and the female resembles the Carabi : 
but in general the sexes are very difficult to be distinguished. 
There are many species of this genus in stagnate waters, which 
