1. II. riparia Rug. — longipalpis Mars. — Ahr. 8. 6.— mini- 
mus Fab. ? — Gyll. — Kugellani Leach. 
Larger than H. testacea ; dull black, head and thorax 
coarsely punctured ; elytra dull castaneous, each having about 
15 regular lines of distinct punctures; palpi and antennse 
bright ochre. 
May : ponds, Hampstead-heath ; Parley-heath, Hants ; 
Glanville’s Wootton, and near Halifax. 
2. H. pusilla Step.pl. l^.f- 3. — nigrita? Germ. p. 93. 
Similar to No. 1, but shorter and proportionably broader; 
entirely of a shining blueish black, excepting the antennae, 
palpi, and legs, which are pale ferruginous. 
Taken by Mr. Gibson in the river Hebden near Halifax, 
near Carlisle, in Devon, &c. 
3. H. elongata Curtis MSS. 
As long as No. 1, but narrower; dull black, crown of head 
and thorax coarsely punctured; elytra shining piceous in- 
clining to castaneous, the suture rather keeled, 6 rows of very 
strong punctures on each, and 3 or 4 less distinct next the 
exterior margin ; palpi ochreous ; legs blackish castaneous, the 
knees and tarsi ochreous. 
Taken by Mr. Gibson in the bed of the river Hebden, and 
communicated by Mr. E. Hobson. 
4. H. testacea Curtis Brit. Ent. pi. 307. 
Specimens of this very distinct species were presented to me 
by Mr. F. Walker, who took them near Southgate: and Mr. 
Dale has found it early in the spring in a pond at Glanville’s 
Wootton, Dorset. 
5. H. pulchella Germ. Ins. Spec. v. 1 .p. 94. n. 161. 
Half as large as No. 4, narrow and very glossy, blackish- 
castaneous ; head black, sparingly punctured ; thorax narrow- 
est at the base, with a channel down each side, strongly but 
sparingly punctured, black, the anterior and posterior mar- 
gins castaneous ; elytra subcastaneous, with about 9 lines of 
deep and large punctures on each, faintest towards the suture 
and apex ; palpi and legs pale ferruginous. 
I took a specimen last May in Dorsetshire, I believe near 
Glanville’s Wootton. 
6. H. rufipes Curtis's Guide , Genus 108. n. 5 . — Very small, 
black, with reddish legs. 
Taken by Mr. Haliday, the beginning of May, under a 
stone in a rivulet at Woodside, Cheshire. 
7. H. minutissima Step. 2. 118. — Gyll. P v.l.p. 136. n. 12.— 
Very minute. Ovate, piceous black ; thorax channeled in the 
middle behind ; elytra smooth, and palest at the apex ; an- 
tennse and legs pale. — Gyll. 
The plant is Hydrochar is Morsus-rance (Common Frog-bit). 
