688 On Aquatic Carnivorous Coleoptera or Dytiscide. 
on the front of the thorax is connected to the large basal band by a small central 
spot ; the marks on the wing-cases are large and very definite, they consist of a 
large basal spot near the scutellum and a humeral mark yellow, then a very 
broad black band just in front of the middle, and behind it a smaller yellow band 
not reaching the suture, then another very broad black band, followed by a yet 
smaller, subapical, broadly interrupted, yellow band, and close to the apex and 
suture a minute yellow spot. 
The species is a doubtful one, but it is more elongate in form than S. hunteri, 
and has a greater extension of the black marks on the upper surface, so that the 
yellow colour is formed into a very definite pattern. From Hydaticus dejeani, 
to which the resemblance in form is considerable, it is distinguished by its larger 
size, and by the yellow spots on the elytra being larger and less numerous. 
Australia. 983. 
1078. Sandracottus guttatus, n. sp.—Lzevigatus, pernitidus, niger, capite ante- 
rius, prothorace lateribus elytrisque maculis distantibus, antennis pedibusque 
anterioribus testaceis. Long. 14, lat. 8 m.m. 
This species is closely allied to H. bakewelli, but is of rather shorter and broader 
form, and the black colour of the upper surface more reduces the size of the yellow 
marks, and the hind legs are rather shorter and thicker. The head is black, but is 
yellowish in front, and has a nearly obliterated yellow mark in the middle in front 
of the vertex. On the elytra there is a spot near the scutellum and a humeral 
mark yellow, also two spots of the same colour just behind the middle, and a 
subapical transverse mark, and a very minute apical spot. In this species the 
yellow marks, none of them, quite touch the epipleure, while in Hydaticus bakewelli 
only the posterior black bands reach the outside, the basal portion of the wing-case 
being yellow at the side as far back as the post-medial black band. 
Australia, 984, 
1079. Sandracottus rotundus, nu. sp.-—Breviusculus, sat convexus, nitidus, niger, 
capite anterius et in medio verticis, prothorace ad latera, elytris margine externo 
maculisque magnis, antennis pedibusque anterioribus testaceis. Long. 13, lat. 
84+ m.m. 
Similar in size and form to the shortest individuals of 8. hunteri, but very 
different in the colour of the upper surface, for black predominates over yellow. 
The head is in large part yellow, the vertex is black, and on the middle between 
the eyes are two black marks confluent with the black colour near the back part of 
the eye, and almost confluent with one another. The sides of the thorax are 
