of Dytiscida Darwiniance. 9 



whole appear fuscous-black ; the usual striae rather strongly 

 marked, and formed of irregular punctures. Body beneath black 

 or fuscous-black. Legs dark yellow or fuscous. 



Extremely variable in colour ; some specimens being nearly 

 black, and others quite pale. 



Hab. Tierra del Fuego. 



9. (10.) C. calidus, Fab. 

 Ovatus, capite thoraceque nigris, elytris crebre nigro-irroratis, 

 macula magna triangulari dorsali prope basin nigrd, lined 

 interrupta basali transversa, marginibus externis elytrorum 

 et lateribus thoracis rufis, striis disci punctatis, subtus niger, 

 antennis pedibusque flavis, posticis fuscis. (L. c. 6 ; lat. 3 

 lin.) 



C. calidus, Fab. Ent. Syst. 1, 193, 27 ; Syst. Eleut. 1, 265. 



Oval ; head black, smooth, with two minute fovese between the 

 eyes in front. 1 borax of the same structure as in the preceding, 

 black ; the lateral margins broadly rufous. Scutellum black. 

 Elytra slightly dilated beyond the middle, thickly irrorated with 

 black ; that colour becoming so much suffused upon the anterior 

 part of the disk, as to form a large triangular black patch, nearly 

 covering the whole width of the base, and extending half the 

 length of the suture; the lateral margins, and a transverse patch 

 at the base interrupted at the suture, rufous ; there is a narrow 

 yellow line upon each side of the suture, and three less distinct 

 ones on the disk, terminated below by the black patch, and ex- 

 tending to the apex ; the usual punctate striae rather strongly 

 marked. Body beneath black. The four anterior legs yellow, 

 the posterior fuscous. 



This beautiful insect approaches in its appearance to Hydaticus, 

 but agrees with the present group in its structure. It may be 

 distinguished by the curious dorsal patch, and the bright red 

 transverse line at the base of the elytra. In one of our specimens 

 this line is divided into four distinct spots. It is a native of Rio 

 de Janeiro. 



CoLYMBETES (Ilybius), Stcpli. III. (M) 5, 394. 

 Ilybius, Erichs. Dytis. 34. 



10. (11.) C. Saulcyii, Dufour MSS. in Collect. Dom. Hope. 

 Ovatus, niger, Isevis, depressus, maculis 2 frontalibus rufis, 

 thoracis angulis anticis elytrisque linea apicali maculd laterali 



