150 ADEPHAGA. [HalipUdce. 



them among the Dytiscida^ but says " that their legs are not sAvimming 

 legs in shape, but only by ciliation, and that they differ so much from 

 the true Dytiscidse in the insertion of the antennse and the number of 

 their joints that they could be erected into a peculiar family, were it not 

 for the fact that Pelohius existed to unite the two groups together ;" there 

 seems, however, to be no real connection at all between Pelobius and. 

 the Haliplidse ; it is most probable that Pelohius ought not to be in- 

 cluded in the Dytiscidae at all, and it is, as Dr. Sharp points out, 

 certainly an erroneous course to include the Haliplidse in one family 

 with the Dytiscidse, and at the same time to keep these latter distinct 

 from the Carabidse ; the peculiar construction of the posterior coxae of 

 the Haliplida?, which are fixed and furnished with large plates covering 

 the greater part of the abdomen, separates them at once from both 

 families ; they possess, it is true, in common with the Dytiscidse, the 

 peculiarity of glabrous antennse (which are 10-jointed instead of 11- 

 jointed as in the latter family), but this is probably only due to their 

 manner of life and the element in which they live, and we need no 

 more class them with the Dytiscidse on this point alone than we should 

 class a whale with a salmon because they both have their limbs modified 

 into fins ; if, however, it is clear that the Haliplidse are to be separated 

 from the Dytiscidse, and there does not seem to be much doubt about 

 the matter, they must be rather classed as a separate group of the 

 Carabidse, and further than this must be considered as completing the 

 circle by being closely connected with the Cicindelidse in the structure 

 of the front of the head, and the insertion of the antennae, the clypeus 

 extending laterally in front of their insertions, instead of not expending 

 so far towards the sides as their insertions, as in the Carabidse. 



It may be said, in conclusion, that if from the fact of their aquatic 

 habits it is considered necessary to class the Haliplidse with the Dyti- 

 scidse, we might just as well class certain species of Curculionidse among 

 the water-beetles proper, notably those belonging to the genus Pliytohius 

 and its allies ; Euhrychius velatus, for instance, is quite as aquatic in its 

 habits as Haliplus, and swims with its hind legs after the fashion of a 

 true Dytiscide. 



Our genera of the Haliplidoa may be divided as follows : — 



I. Terminal joint of palpi snitill, subulate. 



i. Thorax quadrate, with lateral impressed line Brychifs, Thom.i. 



ii. Thorax narrowed in front Halipltjs, Latr. 



II. Terminal joint of palpi conical, longer than the penultimate; 



thorax narrowed in front Cnemidotus, III. 



BRVCHIUS, Thomson. 



This genus, which was separated by Thomson from Ualiylm, comprises 

 three species from Europe and one from California ; they live in running 

 water, and are found attached to sunken logs or to the sides of the banks 

 in mosSj &c. 



B. elevatus, Panz. Pale testaceous ; head thickly and finely 



