DYTISCTDiE. 
Ins. 39 
Hyphydrus ; fourth joint of front and middle tarsi distinctly visible ; 
mesosternum intervening conspicuously between the pro- and meta- 
sternum, its epimera extremely short, almost linear, ventral segments not 
soldered with the coxae; hind coxal cavities not contiguous, but pro- 
longed inwards over the coxal process, so as to become nearly connected. 
To include Hydroporus hansardi, meadforti , and multimaculatus, Clark, 
and S. browni , pi. xi. figs. 140 & 141, obscurus, King George’s Sound, 
p. 385, clavatus (Wehncke, MS.), tarsalis , Sidney, signatus , Murray River, 
p. 386, wehnckii , Australia, p. 387, oscillator , Adelaide, and tasmanicus , 
Tasmania, p. 388 : spp. nn. 
Hyphoporus, id. 1. c. pp. 390 & 859. Allied to the llydroporini ; elytral 
ligula free and abrupt ; terminal joint of front tarsus much shorter than 
the third. To include Hydroporus solieri, Aube, pi. xii. fig. 142, inter - 
pulsus, Walk., Hyphydrus rufus , Clark, and Hyphoporus elevatus and aper, 
spp. iin., 1. c., N. America. 
Paroster , id. 1. c. pp. 391 & 860. Placed after Hyphoporus , elytral 
ridge very little developed ; posterior coxal cavities much exposed, and a 
good deal separated; posterior joints of epipleura very narrow; hind 
tibiao with only the serial punctures on the infero-extornal face. To 
include Hydroporus nigro-adumbratus and insculptilis, Clark, and P. pal 
lescens, sp. n., 1. c. p. 391, pi. xii. fig. 143, West Australia. 
Herophydrus , id. 1. c. pp. 392 & 861. Allied to Ccelambus ; elytral 
ligula abrupt on the posterior face, gradually raised in front ; hind coxal 
cavities approximate ; posterior portion of epipleura very narrow ; 
humeral area of epipleura limited behind by a well-marked raised line. 
To include Hyphydrus guineensis, Aube, and H. heros (Dej., MS.), pi. xii. 
fig. 144, p. 392, verticalis , spadiceus , Madagascar, p. 393, obscurus , Cape 
Town, and oscillator , Caffraria, p. 394 : spp. nn. 
Chostonectes , id. 1. c. pp. 408 & 863. Placed after Ccelambus ; elytral 
ligula absent; posterior portion of epipleura comparatively broad ; hind 
tibiae with only the serial punctures on the infero-external face ; posterior 
femora slender, with rounded outer angle. To include Hydroporus nebu- 
losus, Macl., gigas, Boh., pi. xii. fig. 148, II. bakewelli and Hyphydrus john- 
soni , Clark, aud C. sharpi (Wehncke, MS.), New South Wales, Sidney, 
and latus, Victoria, id. 1. c. pp. 408 & 409. 
Antiporus , id. 1. c. pp. 410 & 864. Placed after Chostonectes', posterior 
portion of epipleura comparatively broad ; hind tibiae punctured on the 
infero-external aspect ; the true fourth joint of front tarsus scarcely 
visible. To include Hydroporus femoralis , Boh., interrogations, gravidus, 
gilberti, and blalcii, Clark, walcefieldi and duplex, Sharp, and A. uncifer , 
pi. xii. fig. 149, New Zealand, and curtulus , Sidney, spp. nn., 1. c. pp. 411 
& 412. 
Macroporus, id. 1. c. p. 416. Placed after Necterosoma ; hind tibiae 
only with serial punctures on the infero-external aspect ; terminal portion 
of epipleura rather broad ; hind femora stout, their postero-external 
angle sharply defined. To include Hydroporus howitti, hamatus, gardneri , 
Clark, pi. xii. fig. 151, and M. lateralis, West Australia, p. 417, solidus , 
King George’s Sound, and ruficeps, Australia, p. 418: spp. nn. 
Deronectes, id. 1. c. pp. 418 & 865. Allied to Hydroporus ; no ligula on 
