688 On Aquatic Carnivorous Coleoptera or DytiscidcB. 



on the front of the thorax is connected to the large basal baud 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 dujeani, 

 to which the resemblance in form is considerable, it is distinguished by its larger 

 size, and by the j^ellow spots on the elytra being larger and less numerous. 



J\u.sti-alia. 983. 



1078. Sandracottus guttatus, n. sp. — Ltevigatus, pernitidus, niger, capite aute- 

 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 epipleurge, 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. 084. 



1079. Sandracottus rotundus, n. 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. 

 8j m.m. 



Similar in size and form to the shortest individuals of S. humeri, 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, ami almost confluent with one another. The sides of the thorax are 



