416 Rev. H. Clark on the Dytiscidse 



examples of it cannot be confounded with those of other allied species, 

 in which no carinations on the elytra are perceptible. 



Apparently a common species near Melbourne. In the cabinets 

 of the British Museum, Mr. Bakewell, Mr. Waterhouse, and the Rev. 

 Hamlet Clark. 



17. H. Wollastonii, n. sp. 



H. ovatus, sat latus, subdepressus, punctatus, rufo- vel flavo-ferrugineus ; 

 elytris fusco lineatis. 



Long. corp. 2 lin., lat. 1 lin. 



Ovate, broad, depressed, thickly punctate, impubescent, rufo- or flavo- 

 femiginous : head obsoletely punctate, rufo-testaceous : thorax broad, 

 subparallel, the sides marginate, the anterior angles well rounded ; the 

 surface is obsoletely punctate, more distiuctly so near the anterior and 

 posterior margins ; at the base are two short longitudinal fovea?, in some 

 examples these fovea? are only part of a short series of corrugations : elytra 

 broad, somewhat rounded at the sides, thickly punctate, with 6 or 8 

 longitudinal lines of fuscous ; in most examples these lines are regular, 

 uninterrupted, parallel, and for the most part of the same breadth as the 

 spaces between them ; in some examples the lines are interrupted more 

 frequently near the suture medially and apically. — The varieties of this 

 species may be grouped under two sections, of which the former pre- 

 dominate numerically : A. Colour flavous; the fuscous lines on the elytra 

 are more sharply defined, and generally uninterrupted ; the apex of the 

 elytra is slightly attenuated. B. Colour rufo-flavous ; the fuscous linear 

 markings on the elytra are somewhat suffused ; in most examples the 

 apex of the elytra is less attenuated. 



I name this species after my friend Mr. Yernon Wollaston, who, 

 by his researches in Teneriffe and Madeira, has added several very 

 interesting species to our lists of the Hydradephaga. 



From the neighbourhood of Melbourne. In the collections of the 

 British Museum, Mr. Bakewell, and the Rev. Hamlet Clark. An 

 example of this species in the British Museum is from " Hobart 

 Town, Van Diemen's Land." 



18. H. dispar, Germ. (Linn. Ent. 1848). 

 Long. corp. 2} lin., lat. 1 lin. 



H. dispar is at once separated from H. Wollastonii by its longer 

 form, black thorax (the marginations being flavous), interrupted and 

 constricted narrow flavous lines on the elytra, and an obsolete tooth 

 near the apex of the elytra. 



This specific name has since been adopted by Le Conte to desig- 

 nate a North American species found near Lake Superior. 



