The Dyticidse are characterized by filiform antennae, con- 
siderably resembling those of the Carabidae; the genus Aga- 
bus of Leach however, and Noterus, vary from the typical 
form in having those organs incrassated; the former at the ex- 
tremity, the latter towards the middle : this alone will distin- 
guish the males from all others of the same family ; and 
Agabus may be further separated from Noterus by its de- 
veloped scutelium : but the singularly formed terminal joint 
of the labial palpi (like a whole-handed glove) in our genus, 
will at once distinguish both sexes from all other genera. 
There are but three species of this genus known, two of 
which are inhabitants of Britain. 
1. crassicornis Fab. — Oliv. 3. tab. 4. f 34. — Marsh ., Gyll. — 
clavicornis DeGeer , — capricornis Herbst. — Geerii Leacli , 
Sam. 
Both sexes of N. crassicornis are distinguished from N. spar - 
sus by their smaller size, and the ochraceous colour of the head 
and thorax. The 5th joint of the antennae in the males is 
much more incrassated, and the elytra are very faintly punc- 
tured. The head beneath and the antepectus at the base of 
the coxae are black, with a broad testaceous stripe down the 
centre ; and the four anterior thighs in the same sex are pi- 
ceous towards their apex. 
I have taken this local insect in ponds and ditches in Norfolk 
in April; but it may be found during the whole year. It has 
been observed in Battersea Fields, on Wandsworth Common, 
Epping Forest, at Whittlesea Mere, and in Cambridgeshire 
and Suffolk. 
2. sparsus Marsh.— Curt. Brit. Ent. pi. 236. 
This is a more abundant species, and may be taken all the 
year in stagnant waters in the neighbourhood of London, in 
Norfolk, Suffolk, &c. It is said also to frequent marshes near 
the sea. 
The plant represented in the plate is Veronica Beccabunga 
(Brooklime). 
