634 On Aquatic Carnworous Coleoptera or Dytiscide. 
The characters of the male are similar to those of H. shuckardi, except that the 
circular plate formed by the three dilated joints of the front tarsi is not quite so 
large and broad, and the four palettes near the base are not so much larger than 
the others. 
The species is closely allied to H. shuckardi, but is easily distinguished ; it is a 
little broader, and (besides the difference in the sides of the thorax of the two 
species) in the one now under consideration the wing-cases have a slight explana- 
tion of their lateral margins near the apex, and their outline is not so continuous 
with that of the thorax, and the scattered punctures are more conspicuous. The 
corresponding sexes of the two should be compared, in order that the sexual 
differences in the outline of the thorax should be allowed for. I have not yet seen 
a rugose form of the female. 
Australia, (King George’s Sound, West Australia). 933. 
982. Hyderodes collaris, n. sp.—Ovalis, robustus, convexus, piceo-niger, clypeo, 
prothoracis lateribus antennisque rufis, pedibus piceo-rufis; prothorace lateribus 
haud discrete et parum crasse marginatis, sed intra marginem conspicue depresso ; 
elytrorum humeris prominulis ; prosterni processu angusto. Long. 19, lat. 11 m.m. 
I have seen only a single individual of this species, it is a rugose female; the 
prominent shoulders and the very narrow and contracted prosternal process and 
metasternal groove, will easily lead to the recognition of the other forms of the 
species when they are discovered. . 
North-west Australia. 934, 
I. 66.—Genus DYTISCUS. 
Clypeus entirely yellow, the yellow colour sharply limited in a straight line from 
the dark colour of the front of the head. Clypeal suture entire, though sometimes 
so indistinct in the middle as not to be perceived at first glance. Elytra with a 
yellow lateral stripe. 
The species* are characteristic of the northern parts of the Old and New Worlds, 
* The following species’ descriptions also refer to this genus: Dytiscus anxius, Mann. (No. 1,285 huj. 
op.) ; North America.—Dytiscus confusus, Motsch. (No. 1,287) !—No. 995; Siberia.—Dytiscus front- 
alis, Motsch. (No. 1,291); Kamtschatka.—Dytiscus fusco-striatus, Motsch. (No. 1,292) ; North America. 
—Dytiscus ibericus, Ros. (No. 1,293); Spain. 
