608 071 Aquatic Carnivorous Coleoptera or DytiscidcE. 



shorter than the inner one, and its extremity a little more slender and more 

 curved. 



The two individuals before me are from diflferent sources; one was recently 

 collected by Mr. Blackburn, the other was formerly in Dejean's collection; they 

 differ in size and minor details, and may very probably prove to be two distinct 

 species. 



Sandwich Islands. 8G9. 



921. Rhantus debilis, n. sp. — Ovalis, hand elongatus, depressus, nitidus, supra 

 subtiliter reticulatus, nigricans, capite anterius et in vertice thoraceque rufescentibus, 

 hoc disco infuscato, elytris nigro testaceoque vermiculatis ; prosterno anterius parum 

 elevato, processu brevi, vix compresso, metasterni lateribus brevibus; tarsis 

 posterioribus unguiculo externo quam interne fere duplo breviore. Long. 8, lat. 

 vix 4 m.m. 



The male has the basal joints of the trout and middle tarsi slightly incrassate, 

 compressed, and furnished beneath with four rows of narrow palettes ; the claws of 

 the front feet are rather short, strongly curved, the anterior one slightly longer 

 than the other. 



Tahiti. 871. 



922. Rhantus annectens, n. sp. — Ovalis, baud elongatus, subdepressus, nitidus, 

 subltevigatus, omnium subtilissime reticulatus, pectore abdomineque nigris, supra 

 rufescens, capite in medio prothoracisque macula discoidali nigricantibus, elytris 

 nigro testaceoque vermiculatis ; prosterno piceo, medio minus alte elevato, processu 

 sat elongate, minus compresso. Long. 11, lat. 5 m.m. 



The male has the basal joints of the front and middle tarsi a little incrassate, 

 and compressed, and furnished beneath with four rows of narrow palettes. 



I have seen only two very mutilated individuals ; the species approximates to 

 Colymbetes pulverosus, Steph., but is rather smaller, and the black marks on the 

 elytra are larger, and form tortuous markings rather than spots : the prosternal 

 process is a little shorter and less compressed, and the front border of the hind coxse 

 approaches nearer to the middle coxae. 



Navigators Islands. 872. 



923. Rhantus plantaris, n. sp. — Ovalis, sat elongatus, angustulus, nitidus, sub- 

 Isevigatus, subtilissime punctulatus, nullo mode reticulatus, testaceus, pectore, 

 abdomine et capite utrinque ad oculos nigris, elytris nigro-irrorati.s, punctis seriatis 

 conspicuis ; prosterno in medio minus elevato, processu sat elongate, parum com- 



