910 On Aquatic Carnivorous Coleopiera or DijliscidcB. 



mark off a broad supra-articular border: the spurs ot the hind tibite are quite 

 distinctly eraarginate at the apex, and the tarsi are terminated by two straight 

 claws of very unequal lengths. The epipleurse are narrow, even at the shoulders. 

 The intermediate femora and tibiae bear long setse on their hinder or inner margin, 

 and the three basal joints of the middle tarsi bear each below, at the inner and outer 

 edge (in each sex), a single elongate depressable or erectile seta: the middle tibife 

 are slender and always without spinules on their lower face; the front tarsi in the 

 female bear long, rigid, §rect setae. The apical abdominal stigmata are quite small. 



The male front tarsi have their circular plate furnished beneath with numerous 

 small palettes, and at the base with three of larger or variable size: the intermediate 

 tarsi are quite simple. The fringing hairs around the front tarsi are very little 

 developed, but this is variable, for they are better developed in Acilius basilaris 

 than in the other species. 



The females show a sexual sculpture on the basal portion of the wing-cases, 

 consisting of rather elongate punctures ; in some species this sculpture extends on 

 to the sides of the thorax. 



Tlie genus is peculiar to the warmer p \rts of the New World, one or two species 

 extending to the southern parts of the United States of North America ; numerous 

 species besides those described doubtless exist. 



Thermonectes simulator is a very peculiar species, entirely resembling in form 

 and markings the species of the European genus Graphoderes." 



I. 71.— Genus (ETHIOy ECTES. {Vide p. G84.) 



The unique species is known to me by two incividuals only ; and its general 

 characters appear to be those of Thermonectes, but the front and middle tarsi bear 

 beneath only short rigid seta?, in place of the elongate ones of Thermonectes, and the 

 middle femora have only some short seta?. 



The prosternum is very thickened along the middle, and the front legs are rather 

 broadly separated, so that although the prosternal process is broad it is not broader 

 than the prosternum between thf: legs : the hind legs are well developed for 

 swimming, and are terminated by two claws of which the outer is nmch more slender 

 than the other, but is not much shorter. 



In all the other characters I can observe, the species agrees wi^h Thermonectes. 



This insect occurs in West Africa ; the species of Thermonectes only in the New 

 World. 



I. 72.— Genus SANDRACOTTUS. {Vide p. G85.) 



Ten species, of rather large size (i to I inch of length), rather convex form, highly 

 polished surface, and beautifully variegate colour, are united to form this aggregate. 

 The antenral portion (i.e., portion anterior to a transverse line drawn across the 



