54 Mr. Babington on a new British Species of Colymbetes. 
moveable, and the three basal joints of the anterior tarsi in 
the males being dilated with small acetabuli; and to the fourth 
division of it, where the four basal joints of the posterior tarsi 
are ciliated beneath in the males. 
CotymseTes (Acasus, §. 4.) rectus, (Bab.). Lineari-oblongus, 
subconvexus, fusco-niger, subtilissime longitudinaliter strigosus, 
antennis pedibusque ferrugineis, elytris apice punctato et strigis 
tribus irregularibus punctorum impressis. 
(Long. corp. 33; lat. 13 Jin.) 
Oval oblong, with the sides nearly parallel and straight, 
slightly broader behind the middle of the elytra, rather con- 
vex, fuscous black above and beneath, head nearly smooth, 
with two large deep punctures in front and two small deep 
fovez before and rather above the eyes, which have a narrow 
rugose line along their upper margin, crown with two round 
red spots. Thorax covered with minute anastomosing longi- 
tudinal striz, which are much stronger near to the lateral 
margins, a shallow depression next to each of the hinder an- 
gles, from each of which an irregular line of punctures ex- 
tends along the hinder margin half-way to the scutellum. 
There is also a line of irregular impressions along the whole 
of the anterior margin, and a faint trace of a dorsal channel. 
Scutellum smooth. Elytra having their sides in continuity 
with the thorax, covered throughout with minute longitudinal 
anastomosing striz, and having three irregular rows of punc- 
tures upon each, with distant scattered dots between them, 
which become more numerous towards the apex; also an ir- 
regular row of numerous punctures on the outer margin. 
Mouth, antenne, and palpi ferruginous ; the labial palpi with 
the second joint rather longer than the third. Legs ferrugi- 
nous, with the thighs darker ; tarsi of the male with the three 
basal joints of the anterior dilated, and the four of the poste- 
rior ciliated beneath ; claws of equal length upon each tarsus, 
but those of the posterior very minute. 
Inhabits Horning marshes, Norfolk, and was found by the Rey. 
J. L. Brown in March, 1839 and ]840.. 
Closely resembling C. branchiatus (Bab.) in form, but be- 
longing to a different subdivision of the section, and in that 
the colour is blueish black, the upper surface almost smooth, 
the legs, antennze, and palpi are much darker, and there is 
also a faint trace of a transparent line upon each of the elytra. 
St. John’s Coll. Cambridge, July 14, 1840. 
