72 HYDROPHILIDA. 
8. Hydrocombus politus. (Tab. II. fig. 10.) 
Ovalis, pernitidus, niger, prothoracis elytrorumque lateribus pallidis ; antennarum basi, palpis pedibusque rufo- 
testaceis ; sat crebre punctatus, elytris ad summum apicem breviter striatis, striis duabus externis anterius 
elongatis, dorso seriebus duabus punctorum remotorum. 
Long. 2, lat. 17 lin. 
Hab. Guatemata, San Gerénimo (Champion). 
The palpi are rather short, entirely yellow. The head and thorax are very shining, 
but are moderately closely punctate. The elytra are rather more sparingly punctate ; 
they have externally two series of punctures which do not reach to the base; and at 
the extreme apex are the very short rudiments of seven or eight other series; there 
are also on the disk two rather irregular series of distant large punctures. The middle 
of the prosternum is obscurely carinate, and is angulate in front. The mesosternal 
transverse process is very prominent. 
SINDOLUS. 
Palpi maxillares perelongati, porrecti, articulo pseudo-basali interne concavo; palpi labiales perbreves, crassi- 
usculi, articulo penultimo quam ultimus crassiore; mentum anterius leviter impressum, margine anteriore 
rotundato; mesosternum lamina longitudinali armatum. Tarsi omnes quinquearticulati. Elytra absque 
stria suturali, 
I have separated under this name two species closely allied both to Philydrus and 
Helochares, and having quite the appearance of short convex Helochares, but distin- 
guished from that genus by the largely developed lamina of the mesosternum, while 
from Philydrus the genus is separated by the elongate maxillary palpi, whose pseudo- 
basal joint is curved in the opposite direction, and by the absence of a sutural stria on 
the wing-case. The submental area is large, as in Helochares, but is not quite so defi- 
nite; that is, it is not so highly polished, and the few punctures on it are fine and bear 
very fine hairs. 
I am not acquainted with any species other than the two here assigned to the genus. 
1. Sindolus optatus. (Tab. II. fig. 12.) 
Ovalis, convexus, ferrugineus, pernitidus ; antennarum basi, palpis tarsisque testaceis, palpis elongatis ; subtiliter 
parum crebre punctatus. 
Long. 23, lat. 14 lin. 
Hab. GUATEMALA, Paso Antonio (Champion). 
Palpi pale yellow, slender and very elongate. The whole of the upper surface very 
shining. Head sparingly but distinctly punctured; clypeal suture obsolete in the 
middle. Thorax finely and sparingly punctate. Elytra very finely and sparingly 
punctate near the suture, more closely and distinctly at the sides and apex. Mentum 
transversely rugose ; the submental polished area large and definite; prosternum very 
finely and indistinctly carinate, the carina hardly at all more elevated on the middle of 
the front margin. Mesosternal lamina very large, its anterior angle rather produced 
and hamate, its lower edge finely setigerous. 
