ABSTRACT
Pronotum widest at base, narrower to much narrower in front, excavated for head, without pubescence, coarsely punctate, lateral margins straight or convex, posterior margin sinuate with medial V-shaped posterior extension, most species with
short, posterolateral carina or plica. Ventral portion of prothorax with notopleural and pleurosternal sutures. Prosternum at base elevated to form a kind of ventral head rest, in repose, prosternal process long and forming a complex junction with the mesoventrite (=mesosternum, of authors), bordered laterally by raised lines or carinae (absent in Apteraliplus). Procoxal cavities round, open behind externally but closed internally. Procoxae globular to subglobular, trochantin not visible. Protrochanter short, globular. Profemur thickened medially, with a row of broadly spaced, stiff, elongate setae on anteroventral surface. Protibia slender with rows of stiff, elongate setae on anterior, dorsal and posterior surfaces, and row of long, natatory setae on dorsal surface. Protarsi slender and elongate, protarsomere 1 longer than protarsomeres 2, 3 and 4 which are longer than wide, protarsomere 5 longest, with row of long, natatory setae on dorsal surface of protarsomeres 1 to 4; males with protarsomeres 1 to 3 perceptibly broader, apex of protarsomere 1 and ventral surface of protarsomeres 2 and 3 with some short, unmodified setae; two rather elongate claws (very long in Brychius) present on tarsomere 5 with inner margins minutely serrate to pectinate.
