128 E. T. Atkiuson — Catalogue of the Family Dytiacidse. [Supplfc^ 



and Dytisci CompUcati (p. 964), according to whether the metathoracic 

 episteraum reaches the intermediate coxal cavity or not. These are 

 further sub-divided into the tribes Noterides (p. 260,944), Hydroporides 

 (p. 319,950), Colymbetides (p. 490,956), and Hydaticides (p. 647,959), 

 but the details of this arrangement cannot be followed here. 



As already noticed in the * Catalogue of the Carabidse,' Dr. Horn raises 

 iheSaliplinit Amphizoa, and Hydrachna* (Pelobius), to the rank of families. 

 There is a strong consensus of opinion that to elevate these aberrant genera 

 to the position of families and thus place them on a level with a family 

 like the Carabidce is a step to be regretted as likely to lead to the un- 

 necessary splitting up of other families on equally good grounds. The 

 proper place for these groups appears to be as sub-families of the aquatic 

 carnivora, uniting the Dytiscidce proper with the terrestrial carnivora. 

 For convenience the name Dytiscidce may be applied to the whole group. 

 Lacordaire f writes of the Haliplini that ces insectes n'appartiennent 

 reellement pas non plus k la famille {Dytiscidce) par leurs pattes ; les 

 tarses posterieurs surtout resemblent completement ^ ceux d'une foule des 

 Carabiques, leurs articles 6tant greles, allonges et chacun un peu renfl6 a 

 leur extremity.' He adds that the characters given should place them at 

 the head of the Dytiscidce which they connect with the Carabidce. Dr, 

 Sharp X in his paper on the classification of the Dytiscidce, removed the 

 Haliplini from that family and left it to ' the Carabophiles to decide 

 whether they should be considered Carabidce or form a distinct family.' 

 Subsequently, however, he makes them a separate family §. 



Lacordaire makes the genus Ampliizoa also a tribe or sub-family, 

 * qui pr^sente un singulier melange des caracteres des Dytiscides et des 

 Carabiques. Par ses organes buccaux, sa t6ce, ses antennes, et la non- 

 contiguit6 des parapleures meta-thoraciques avec la base de I'abdomen, 

 il appartient aux premiers, tandisque par ses pattes completement ambula- 

 toires, son prosternum regu dan un sillon du mesosternum comme chez 

 les Carabides, et la separation de ses saillies coxales, il rentre dans les 

 seconds.' It thus diminishes the differences between the aquatic and the 

 terrestrial Carnivora. Leconte originally placed this singular genus in 

 a distinct family and Chaudoir makes it a distinct group near to Trachy- 



* I do not understand the grounds on which the name Hydrachna for this genua 

 (1801) has been sunk in favour of Paelohius (Pelohius) Schonherr (1806), the species 

 Harda Herbst,' the type given by Fabricius, being still considered as belonging to 

 the genus. 



t Gen. Col. i p. 410. 



i G. R. Soc. Ent Belg., xxiii, 1880, p. cxlvii ^ Dytisc, p. 971. 



§ Biol. Centr. Amer,, Col, i (2), 1882, p. 1. 



V 



