888 On Aquatic Carniworsus Coleoptera or Dytiscide. 
Colymbetes gaudichaudi, its swimming legs being more slender and its hind coxe 
having the front border less arched, it has scarcely any trace of lobing of the joints 
ot the hind tarsi, and the outline of its thorax and elytra are less perfectly 
continuous than they are in C. gaudichaudi. 
The two species are found in western South America. 
I. 50.—Genus AGAMETRUS. ( Vide p. 547.) 
This aggregate comprises only three species; the individuals possess a very 
polished surface, and the outline of the thorax and elytra is very continuous, the 
former is destitute of any raised margin at the side. 
The prosternal process is broad, flat and acuminate ; the epipleurze are quite 
narrow behind the middle: the hind coxe are very large, and the wing of the 
metasternum deflexed outside it is a very short, parallel sided, or linear band. The 
coxal lines are quite absent. 
The genus is very closely allied to Leuronectes, but is well distinguished by the 
absence of the coxal lines. 
The species are found in South America, 
I. 51.—Genus AGABINUS, (Vide p. 548.) 
This is an autogenus, comprising a single species, having quite the appearance of 
one of the smaller, shining black Agabi. Coxal lines deeply impressed, nearly 
straight ; the hind coxa small, its front border scarcely at all arched; the coxal 
border very distinct and continued forward till it meets the front border of the 
coxa at nearly a right angle, the wings of the metasternum are large, and not 
deflexed outside the coxa. Epipleurze narrow behind the middle ( but still broader 
than in Agabus). Swimming legs slender. Prosternal process rather broad, strongly 
acuminate, its basal portion with a peculiarly thick margin, but its apical half quite 
without margin. 
These characters are exhibited only by a single species; it has a very polished 
surface and is in appearance very similar to Agabus aubei, (Metronectes). The pecu- 
har structure of the coxal processes, gives it a superficial resemblance to Noterini, but 
it has no real approximation thereto, and when the coxal processes are compared 
with those of Dytiseus maculatus (Gen. Platambus) and with those of a member of 
the Noterini, it is readily seen that even in this portion of the structure the relation- 
ship is with the Platambus, and not with the Noterini: with Agabus pictipennis 
(another member of Platambus found in Japan) the resemblance is still greater, and 
the true position of the genus is demonstrated in an irrefragable manner by this 
latter species. Although Agabinus has not the broad epipleure of Platambus, still 
it shows an approach thereto, for they are quite distinctly broader than in Agabus. 
