856 On Aquatic Carnivorous Coleoptera or Dytiscide. 
Joint of the tarsus. The front and middle tarsi have their third joint short and 
broad not bilobed, but with the outer portion of its upper surface excavate 
or channelled for the reception of the base of the terminal joint: this latter is very 
elongate, two or three times as long as the third jomt. The epipleura has at 
the shoulder a well marked genicular fossa, limited behind by a distinct raised line. 
This, like the allies, is an inhabitant of South Africa. 
I. 27,—Genus PRIMOSPES. (Vide p. 372.) 
This is at present an autogenus. The insect has much the size of a large 
Hydroporus and is similar thereto in form. The surface above and below is densely 
and finely punctate, and the sculpture on the anterior parts of the upper surface 
becomes obsolete. The head is rather truncate in front. The epipleure of the elytra 
possess at the shoulder an indefinite genicular fossa not limited behind by a definite 
raised line : the swimming legs are quiteslender. In other respects the characters 
are those of Hydropeplus. 
This species is from Capetown. 
I. 28.— Genus CH LHYDRUS. (Vide p. 373.) 
This is again as yet an autogenus: it consists of a species whose individuals have 
about the size of the Celambi, and are of short peculiar form, suggesting themselves. 
as an intermediate between the Coelambi and Hyphydri. The head is subtruncate 
in the middle in front, and not in the least margined ; the prosternal process is 
rather short and very acuminate, its apex is decurved, and in repose just rests on 
the extremity of the very short and slender inter-coxal process of the metasternum ; 
this is a little curved towards the mesosternal fork, which, however, it does not 
attain, and it is obscurely grooved in front. The hind cox are very large, and their 
cavities are rather broadly separated, and quite exposed, the coxal processes being 
adpressed, and without any trace of external acute angle. The swimming legs are 
rather short, and are moderately stout, the upper third of their tibiew, being a 
good deal more slender than the apical portion, the spurs are not straight but 
distinctly slightly crooked or sinuate. The front and middle tarsi have the third 
Joint rather small; the terminal joint is likewise not greatly developed, it is however 
exserted, and as long as the third joint. The epipleura has a definite genicular fossa 
at the shoulder. 
This insect is likewise an inhabitant of Southern Africa. 
