On Aquatic Carnivorous Coleoptera or DytiscidcB, 729 



short scratches which, are rather more widely separated from one another than in 

 the form above mentioned: the size of a large specimen is 28} m.m. long, 15f m.m. 

 wide, and 9 5 m.m. high. 



A few specimens from Sumatra, Borneo and Labuan, seem to be intermediate 

 between the large broad forni just mentioned, and the ordinary East Asiatic form. 



In Java the species appear to be very common, and the individuals from there 

 are of a rather short, broad, robust form, with the yellow margin to the elytra 

 broad, and the patches of pubescence on the two basal joints of the male intermediate 

 tarsi broad, while the sexual sculpture of the females is slight or entirely wanting ; 

 a male measures 25 m.m, long, by 14 m.m. broad, by 85 m.m. high. 



The Cybister temninckii of Aube is said to be from Java, it differs from all other 

 Javanese individuals I have seen by its very elongate form ; one of the individuals 

 which served Aubd for his description is before me, it is a female, with slight sexual 

 sculpture, and is fully 30 m.m. long, 15 m.m. broad, by 9 m.m. high. 



A small series from Celebes, Batchian, Amboina, differ scarcely at all from the 

 Javanese individuals, but are perhaps on the average a little larger in size ; of four 

 females before me from this locality, three have no sexual sculpture, and on the 

 fourth the sculpture is but slight. 



A single female from Menado, agrees with the larger of the Philippine Island 

 forms, except that the scratches forming its sexual sculpture are finer and 

 denser. 



I have seen no specimens from New Guinea, though the species no doubt occurs 

 there. 



In Australia the species is common, and I have before me a series of about 

 twenty-four specimens from localities which indicate the species as there very 

 widely distributed ; they differ scarcely at all from the East Asiatic form as found 

 in China and Japan, but are perhaps on the average slightly larger in size, and the 

 dark colour on the head usually approaches in the middle rather nearer to the 

 labrum ; the male tarsi are the same as in the Chinese form, and all the females 

 show a fine sexual sculpture except one which is quite smooth. 



In New Caledonia the species appears also common ; the individuals are rather 

 shorter than the Australian individuals, and the patches of pubescence on the male 

 intermediate tarsi are rather broader, so that here the specimens seem to approximate 

 to the Javanese forms. The females have a slight sexual sculoture. 



One very large female from this locality is remarkable, it attains 29i m.m. in 

 length by 16 m.m. broad, and has a largely developed sexual scidpture, so that it 

 differs but little from the broader of the two forms mentioned as found in the 

 Philippine Islands. Cybister artensis and C. novae-caledoniaB, as well as Dytiscus 

 hamatus described by Montrouzier from this locality seem all to be merely varieties 

 of D. tripunctatus. 



From Ceylon I have seen only a single pair, which are very small, but do not 



