156 Browne: The Aquatic Coleoptera of the Isle of Man. 
O. lejolisii Rey and Muls. German (Peel); Mallew (Castle- 
ton). 
Hydrena testacea Curt. Lezayre (Sulby R.). 
H. riparia Kug. Andreas; Lezayre. 
H. nigrita Germ. Arbory (Balladoole) (Bailey) ; Lezayre 
(Sulby R., two or three specimens). 
H. gracilis Germ. Mallew (Silverburn) ; Rushen (Colby 
Glen and Kentraugh) (Bailey); Ballaugh (in the glen); Ger- 
man (R. Neb); Lezayre (Sulby R., etc.) ; Santon. 
H. atricapilla Wat. Rushen or Arbory ? (Colby Glen), one 
specimen (Bailey). 
H. brittent Joy  Arbory (Balladoole) (Bailey). 
Cyclonotum orbiculare F. Rushen (Gramma, Port Erin) 
(Bailey). 
The great majority of the Manx Water Beetles belong to 
the group which Watson termed ‘ British,’ consisting of species 
which are spread more or less generally over the whole of Great 
Britain, and also Ireland! But there are a certain nimber of 
the Manx species which are decidedly localised in the British 
Islands. Some belong to a group which has its headquarters 
in the south and west of Britain, a group which, for the most 
part, turns up again in the south and west of Ireland. To 
this group which, by some, is regarded as probably the oldest 
part of the British fauna and Flora* belong such species as :— 
Bidessus minutisstmus. 
Gyrinus urinator. 
O thebius lejolisit. 
B. minutissimus is so far only recorded from Devon S., 
Wigtown and Kirkcudbright, Kerry S., Cork Mid (of Praeger) 
and Dublin, but, as I have already remarked, it almost certainly 
occurs in suitable rivers in the west of England, and perhaps, 
also all round Ireland. 
G. urinatoy occurs in Devon N. and S., Hereford, Somerset 
N., Dorset, and Sussex E. In Ireland it has occurred in Kerry 
S., and Cork W. (of Praeger) and I have a single specimen 
from Toome bridge (Co. Antrim), taken by Mr. R. Welch 
two years ago. There are English records for Yorks. N.E., 
and Durham, but the centre for the species in Britain is dis- 
tinctly south-western. 
O. lejolisit is now known from various places, ranging from 
the Isle of Wight round the western coast to the North Ebudes,t 
and almost certainly occurs all round Ireland, though the 
* Vide Forbes, E., The Geological Relations of the Fauna and Flora 
of the British Islands, etc. ‘Mem. Geol. Survey,’ Vol. I., 1846; also 
Scharff, Carpenter, etc. : 
+ The Aquatic Coleoptera of the North Ebudes, ‘ Ann. Scott. Nat. 
ste oie 
Naturalist, 
