DYTISCUX®. 
Ins . 41 
Agabinu8 , id. 1. c. pp. 548 & 888. Placed after Agametrus. Type, 
Colymbetes glabrellus , Motsch. (figured, pi. xv. fig. 179). 
Aglymbus , id. 1. c. pp. 596 & 893. Allied to Copelatus ; coxal 
lines quite obliterated ; upper surface sculptured with short lines. To 
include C. rufipes, Brull6, Agabus leprieuri (figured, pi. xv. fig. 189), and 
pallidiventris , Aub6, and A. sculpturatus , Para, p. 596, optatus, Colombia, 
gestroi and brevicornis, Abyssinia, p. 597, spp. nn. 
Agabetes , id. 1. c. pp. 599 & 894. Allied to Matus ; prothorax without 
lateral margin ; uppor surfaco densely sculptured ; coxal lines con- 
spicuous, parallel in front, greatly divergent behind, and marking off a 
large broad coxal border. Type, Colymbetes acuductus , Harr, (figured, 
pi. xvi. fig. 191). 
Lancetes , id./, c. pp. 602 & 897. Allied to Agabus and Bhantus ; 
extremity of elytra sinuate-truncate ; palpi scarcely if at all emarginate at 
the apex ; coxal processes elongate, deeply divided, and much divergent. 
To include Colymbetes lanceolatus , Clark (figured, pi. xvi. p. 194), nigri- 
ceps (1. c. fig. 195), and proemorsus, Erichs., Rhantus marginatus , Steinh., 
and several other described species ; add A. unguicularis, sp. n., 1. c. p. 603, 
Chili. 
Prodaticus , id. 1. c. pp. 648 & 906. Allied to Hydaticus ; coxal lobes 
broad, their supra-articular border rather narrow, claws of hind feet nearly 
equal in length. Type, P.pictus, sp. n., 1. c. pi. xvii. fig. 206, N. India. 
C Ethionectes , id. 1. c. pp. 684 & 910. Allied to Thermonectes ; coxal 
lines distinct in their hinder portion, supra-articular border broad; 
middle femora with only short setae. Type, (E. optatus , sp. n., 1. c. p. 685, 
pi. xvii. fig. 213, Guinea. 
Rhantaticus, id. 1. c. pp. 691 & 911. Allied to Sandracoltus. Type, 
Hydaticus signatipennis , Lap. (figured, pi. xviii. fig. 215). 
Spencerhydrus , id. 1. c. pp. 701 & 916. Allied to Homceodytes ; anterior 
border of hind coxae approaching rather closely to the middle coxae. To 
include S. pulchellus, p. 701, latecinctus , pi. xviii. fig. 219, and semiflavus, 
Australia, p. 702 : spp. nn. 
Homceodytes, id.. 1. c. pp. 703 & 916. Allied to Cybister ; coxal lines 
absent ; unguicular cleft broad and rounded at base. To include Dy - 
tiscus atro.tus , Fabr., Cybister scutellaris , Germ., and hoolceri , White 
(figured, pi. xviii. fig. 220). 
Megadytes , id. 1. c. pp. 704 & 917. Allied to Cybister ; coxal lines 
present ; unguicular cleft narrow and angular at base ; hind tarsi in $ 
terminated with two distinct claws ( $ always with two claws, but the 
inner one often rudimentary). To include several species described by 
authors under Cybister and Trogus , and AT. expositus , fig. 221, Chili, p. 705, 
fraternus , fig. 222, pi. xviii., Panama, Guatemala, Guadeloupe, St. 
Domingo, Detnerara, p. 708, flohri, Mexico, p. 709, obesus , Panama, p. 710, 
perplexus , S. America, p. 711, gravidus, p. 712, and ducalis, Brazil, p. 713 : 
spp. nn. 
Mesonoterus , id. Biol. Centr. Am. Col. i. (2) p. 4. Allied to Pronoterus ; 
front legs shaped as in Noterus, but more slender ; swimming-legs also 
more slender and less powerful. Type, M. Icevicollis, sp. n., 1. c. pi. i. fig. 2, 
Guatemala. 
