On Aquatic Carnivorous Coleoptera or Dijtiscidce. 265 



convexus, castaneus, nitiJus, lajvis, sed elytris punctis magiiis, imbricatis, numerosis, 

 basin versus evanescentibus; sutura Igevi. Long. 85, lat. 2 m.m. 



I have seen only females, they are perfectly similar to Synchortus duplicatus 

 except in the tarsi, and in the sculpture of the elytra, and I have little doubt the 

 two are the sexes of one species. 



Madagascar. 520. 



19. Hydrocanthus rugoso-punctatus, Wehncke, Berh Zeit. 1876, p. 221. — Ovalis, 

 sat convexus, castaneus, nitidus, elytris punctis magnis, imbricatis numerosis, basin 

 versus hand subtilioribus ; sutura Isevi. Long. 3f m.m. lat. 2 m.m. 



I have seen a single specimen, it is a female, and distinguished from Hydrocanthus 

 asperatus (No. 18), by the fact that the punctures on the basal portion of the elytra 

 are as coarse as those on the apical portion. 



Madagascar, (Wehncke). G09. 



I. 6.— Genus NOTERUS. 



Anterior tibia with indefinite outer apical angle, and with rather long curved 

 spur ; antennae more or less incrassate ; hind tibial rather slender, scarcely flattened. 

 The six species are found in the Eurojiean region and Japan. 



20. Dytiscus clavicornis, de Geer. Noterus clavicornis, M.C. — Ovalis, sat 

 convexus, fere angustus, sat nitidus, testaceo-castaneus, elytris punctis magnis, 

 anterius subseriatis, ante basin desinentibus. Long 4, lat. 2s m.m. 



Mas, antennis incrassatis, irregularibus, articulis quinto et sexto pra^sertim majori- 

 bus, illo quam hoc (quo valde transverse) duplo longiore ; capite subtus prosternoque 

 utrinque nigro-maculatis, hoc medio deplanato. 



Fcm., antennis fere regularibus, corpore subtus concolore ; prosterno medio trans- 

 versim convexo. 



This species varies but little ; the elytra and ventral segments are sometimes of 

 more obscure colour. 



Europe. From Scandinavia to Portugal. Not common. 521. 



21. Dytiscus capricornis, Herbst. Noterus semipunctatus, M. C. — Ovalis, convexus 

 sat nitidus, castaneus, antice dilutior ; elytris punctis magnis, profundis, basin versus 

 desinentibus; prosterno medio carinato. Long. 4i, lat. 2h m.m. 



Mas, antennis incrassatis, irregularibus, articulis 5" et 6° longitudine subtequalibus 

 haud transversis ; capite subtus prosternoque latius nigricantibus ; femoribus cum 



