On Aquatic Carnworous Coleoptera or Dytiscide. 865 
fifth joints. The coxal lines have their terminal portions much turned outwards, 
and in their anterior parts are much less widely separated from one another than 
they are in Antiporus. The ligula on the inner face of the elytra is quite distinct 
although short and broad. The characters in other respects are much those of 
Antiporus. | 
The genus is peculiar to Australia and Tasmania. 
I, 39.—Genus MACROPORUS. (Vide p. 416.) 
This is an aggregate consisting of six species; the individuals are of large size 
amongst their allies, the largest attaming 7 m.m. of length, but vary much in 
width, they are convex beneath ; the upper surface is distinctly pubescent, the lower 
is coarsely punctured : the size attained is greater than im any other Hydroporini, 
and equals that of the members of the Hyphydrini. 
The hind coxe have a large area, and are elongate even quite near the middle 
longitudinally of the body, their anterior border does uot stretch abruptly forwards, 
so that the length of the coxa at its longest part is not twice what it is at its shortest 
part ;.the coxal lines are subparallel, being a little divergent both in their anterior 
and posterior portions ; and their articular cavities are but slightly separated ; the 
femora are broad and sublaminate (showing when viewed from above a distinct 
lamina at their outer hinder portion, which when the tibia is flexed receives and 
covers its base: the hind tibice are glabrous externally, with a series of setigerous 
punctures near the margin: the epipleura of the wing-case is moderately broad in 
its terminal portion, and is impressed at the humeral angle, but there is no trace of 
any raised line limiting externally this area: there is no ligula on the inner 
face of the wing-case : the real fourth joint of the front tarsus cannot be perceived. 
The genus is especially characterized amongst the Hydroporini by the well 
developed swimming legs, these organs attaining in Macroporus a perfection greater 
than in any other Hydroporini. In some other respects there is considerable 
variety amongst the species ; M. lateralis, has the terminal joint of the front tarsus 
quite short, and in fact approximates to Hyphydrus by the structure of this part, 
while the other species have the joint alluded to either considerably or greatly more 
elongate. 
The species are found only in Australia and Tasmania. 
I. 40.—Genus DERONECTES. (Vide p. 418.) 
Grovp 1. 
The characters assigned to the first group of species of Deronectus (see p. 419), 
justify the association together of about twelve species, which when carefully 
examined exhibit nevertheless important structural differences amongst themselves: 
