24 JOURNAL R. A. s. (ceylon). [Vol. III. 



transverse impressions. The head of the insect is rather large 

 and even. The mandibles are furnished with an obtuse sub- 

 apical tooth, the two lower thirds are ciliated. The maxillae 

 have the apex of the outer lobe externally enlarged^ rounded 

 off, and furnished with three strong teeth replaced by cilia on the 

 inside; the inner lobe is conic and similarly provided with teeth 

 and cilia, however, much thinner and finer. The maxill. palpi 

 are robust, the last joint is inflated <at the base. The antennal 

 club is hairy, dark (whilst the remaining joints are yellowish), 

 conic, and somewhat securiform, the sixth joint being inserted on 

 one side of the seventh. The legs are robust, the tibiae slightly 

 curved, obliquely truncated at the end, furnished with spines 

 along the outside, and with distant cilia along the inner. 



21. Hydrochus lacustris. N. 



H. elongatus, subdepressus, supra metallicus, iridescens, subtus piceus, 

 'pedibus, antennis, palpis elytrorumque margine magis minusve brun- 

 ^neis, mento cyaneo. Long. corp. 1-1^ lin. 



Palpi maxill. robust! art. ultimo elliptico leviter inflate. Mandibulse 

 apice bifidae. Antennarum clava dense pilosa. Thorax oblonge qua- 

 dratus basin versus angustatns, basi medio productus, cum capite pro- 

 funde punctata Elytra ad humeros oblique truncata, apicem versus 

 sat fortiter angustata, profunde striato punctata. Tibiae extus 

 spinuloses, 



Specimina nonnulla in locu Colomb- legi. 



The head is robust, broader than the thorax, the eyes large 

 and prominent. The femora, the last joint of the maxill. palpi, 

 the mandibles, and the tarsal joints are dark towards the apex 



22. Hydrous rufiventris. N. 



H. ovatus, convexus, supra oleagino-niger, subtus obscure f errugineus, 

 pedibus dilute piceis, labro seneo, reliquis oris partibus cum clypeo test- 

 aceis. Long. corp. 9 lin. 



Palpi maxill. articulis apicem versus abruptius incrassatis, art 3° 

 quarto sesqui longiore. Antennas art. 7-8 fortiter perfoliatis, ultimo 

 acuminate Caput antice utrinque punctulorum serie subsemicirculari 

 et ad oculorum marginem interiorem impressum. Thorax punctulorum 

 seriebus 4 lateralibus, 2 subapicalibus obliquis abbreviatis signatus. 

 Elytra subtiliter striato-punctata. Tarsi omnes unguibus basi fortiter 

 uni-dentatis. Carina prosternalis cultriformis. 



Specimen singulum f . nocte ad lumen cepi. 



