272 On Aquatic Carinvorous Coleoptera or Dytiscide. 
nm 
The only individual I have seen is a female, and it has an oblong depression on the 
apical ventral segment, which at the extremity is divided by a short plica. 
bo 
“J 
Panama. 5: 
41. Canthydrus dilutus, n, sp.—Ovalis, sat convexus, posterius acuminatus, 
testaceus, nitidus, elytris crebre obsolete punctatis. Long. 2%, lat. 1; m.m. 
Though the species is pretty closely allied to Hydrocanthus tenuicornis (No. 
39), it is of narrower, more elongate, and convex form, and the elytra are much 
more obsoletely punctured: there does not appear to me to be any difference in 
the sexes, except in the tarsi. 
Brazil; Bahia. 505. 
42. Noterus buqueti, Lap. Hydrocanthus buqueti, M.C!_—Ovalis, latus, minus 
convexus, breviusculus, pernitidus, sanguineo-rufus, elytris iridescenti-fuscis, 
maculis subdistinctis quatuor apiceque rufis; prothoracis margine laterali lato. 
Long. 3, lat. 1¢ m.m. 
I have seen but a single individual from Dejean’s collection, the species is 
readily distinguished from the allies by the broad thoracic margin, which is 
formed as in the genus Hydrocanthus. The spots on the elytra are not very 
distinct ; besides the four which form a transverse row across the middle, there 
are other two near the apex which are scarcely to be distinguished owing to the 
more dilute colour of the hind part of the elytra. The individual (in M. de Bou- 
youloir’s collection) is I think a female, but shows no apparent peculiarity, 
South America, (Cayenne). 504. 
43, Canthydrus remator, n. sp.—Ovalis, sat convexus, et sat elongatus, nitidus, 
ferrugineus ; elytris vix obscurioribus, fere impunctatis, seriebus punctorum 
duabus sat distinctis; prosterni processu dense punctato, canaliculato. Long. 3, 
lat. 1 m.m. 
South America, (Uruguay). 526. 
44, Canthydrus curtus, n. sp.—Ovalis, latiusculus, minus elongatus, sat convexus, 
nitidus, rufus; elytris iridescenti-fuscis, serie punctorum sat distincta ; prosterni 
processu canaliculato, Long. 3, lat. 1s m.m. 
This species is shorter, and so comparatively broader than its allies, and the 
under surface is pale and unicolorous. In each sex the apical abdominal segment 
