'2 1 2 Oil Aquatic Carnivorous Coleoptcra or DijtiscidcB. 



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. 



Panama 527. 



41. Canthydrus dilutus, n. sp. — Ovalis, sat convesus, posterius acuminatus, 

 testaceus, nitidus, elytris crebre obsolete punctatis. Long. 2f, 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 huqueti, M.C. — Ovalis, latus, minus 

 convexus, breviusculus, pernitidus, sanguineo-rufus, elytris iridescenti-fuscis, 

 maculis subdistinctis quatuor apiceque rufis ; prothoracis margine laterali lato. 

 J,ong. 3, lat. ]f m.m. 



I have seen but a single individual from Dejean's collection, the sjDecies 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- 

 vouloir's collection) is 1 think a female, but shows no apparent peculiarity. 



ijouth America, (Cayeime). 504. 



43. Canthydrus remator, n. sp. — Ovalis, sat convexus, et sat elongatus, uitidus, 

 ferrugineus ; elytris vix obscurioribus, fere impunctatis, seriebus punctorum 

 duabus sat distinctis ; prosterni processu dense punctato, canaliculato. Long. 3, 

 lat. If m.m. 



South America, (Uniguay). 526. 



44. Canthydrus curtus, n. sp. — Ovalis, latiusculus, minus elongatus, sat convexus, 

 uitidus, rufus ; elytris iridescenti-fuscis, serie punctorum sat distincta ; prosterni 

 processu canaliculato. Lung. 3, lat. 1| 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 



