Cliemidotll^.'] ADEPIIAGA. l.')7 



jiatcli ; elytra depressed on disc, with ten rows of large black punctures 

 on each which become larger towards base, those at base being especially 

 conspicuous ; on the centre of the disc is a more or less distinct dark 

 patch, and there are other indistinct dark markings towards apex. L. 

 3|-4 mm. 



Ponds, &c. ; local ; Peckham, Putney, Lee, Gravesend ; Whitstable ; Deal ; Hun- 

 stanton; Birchinfrton ; Devonshire (Kxminster) ; has occurred, I believe, in York- 

 sliire ; not recorded fro;n tlie Nortlumiberlaiid district. Scutlaiid, very rare, Clyde 

 district (" Ayrshire," Hislop). 



Between the Haliplidie and tlic Dytiscidte come the two families 

 Amphizoidai and Pelobiida;, which contain only two or three species 

 each, but are so isolated that they cannot be attached to any other 

 family. 



AMPHIZOID.^. 



There has been considerable doubt among authors a? to the position of 

 this family, whicli comprises the single genus Aniphizoa, containing three 

 species from Is'orth America, of heteronierous appearance, and about 

 12 mm. long. These insects in many respects resemble the Parnida?, being 

 equally poor as swimmers, and being found like them clinging to logs or 

 stones beneath the surface of the water. Leconte, the original describer 

 of Amphizoa, considered it a type of a family distinct both from the 

 Carabida) and the Dytiscidae ; Lacordaire classified it among the Dyti- 

 scidae, while other authors have described it as a heteromeroid form of 

 (Jarabida). Dr. Sharp (Trans. Eoyal Dubl. Soc. vol. ii. ser. 2, p. 847) 

 discusses the question at length, and while allowing that, strictly speak- 

 ing, Awjyliizoa is neither a Dytiscid nor a Carabid, yet he comes to the 

 conclusion that it must be classed with the Dytiscidse ; to this conclusion 

 he is in a great measure led by the fact that in Amplthoa the meta- 

 thoracic episterna reach the middle coxal cavity, which is therefore 

 enclosed by four pieces instead of three, a peculiarity that until recently 

 has been found in no other beetles except this genus and the DytiscidiT? : 

 Dr. Horn, however, has since discovercvl tiiat this character also exists in 

 the strange genus Mormolycc (CarabidiB, p. 101), and in consequence 

 Dr. Sharp (Trans. Ent. Soc. London, 1882, parti, p. 67) has modified his 

 views and treats it " as an aggregate (not as a family) occupying an in- 

 termediate position ])etween the Carabidic and Dytiscidae, but a member 

 of neither." Dr. Horn believes that it is far less a Dytiscid than a Cara- 

 bid. On the whole, Amphizoa, to whichever side it may most incline, is 

 a decided link between the okl Geodephaga and Ilydradephaga, and 

 makes it the more impossible to disconnect them : it may perhaps be 

 noticed in conclusion that another point of transition in Amphizoa is 

 found in the more or less distinctly punctate basal joints of the 

 antenna3. 



It may seem o\it of place to discuss tliis qucstiim in a book licaiiug 

 especially uu Dritish Enluinulogy, but it i.^ impossible to avoid all allu- 



