HYDROPHILIDiE. 
Ins . 47 
0. abyssinicus, Reitt., is quite distinct from bicolor, Germ. ; Reitter, Wien, 
ent. Zeit. i. p. 170. 
Hydroma pallidipennis, Cast., = Ochthcbius marinus , Paylc., and H. 
striata , Cast., = 0. bicolor, Germ. ( rufo-marginatus , Steph.) ; Yon Hey- 
den, Bull. Soc. Ent. Fr. (6) ii. pp. xii. & xiii. 
New genera and species : — 
Oocyclus , Sharp, Biol. Centr. Am. Col. i. (2) p. 61. Allied to Hydro- 
bius , but with a superficial resemblance to Cyclonotum ; to include 0. 
vcstitus , Mexico, p. G2, brevicornis (type), pi. ii. fig. 9, and maculatus , 
Guatemala, p. 63 : sp.p. nn. 
Metacymus , id. 1. c. p. 65. Allied to Anaccena ; head broad, dilated 
before the eyes ; labrum scarcely visible ; antennae seven-jointed, and 
very short. Type, M. parvulus, sp. n., 1. c. p. 66, Chiriqui. 
Hydrocombus, id. 1. c. p. 70. Allied to Cymbiodyta, but with a trans- 
verse elevation on the mesosternum. To include H. brevicollis and fra- 
terculus, Mexico, p. 71, and politus, pi. ii. fig. 10, Guatemala, p. 72 : spp. nn. 
Sindolus, id. 1. c. p. 72. Allied to Philydrus and Helochares : lamina' 
of the mesosternum largely developed ; maxillary palpi elongate ; elytra 
with no sutural stria. Types, S. ojjtatus, pi. ii. fig. 12, Guatemala, and 
mundus , Mexico, spp. nn., 1. c. pp. 72 & 73. 
Chasmogenus , id. 1. c. p. 73. Allied to Helochares ; mentum with a 
broad curved emargination in front. Type, C. fragilis , sp. n., 1. c. pi. ii. 
fig. 13, Guatemala, Panama. 
Derallus , id. 1. c. p. 77. Allied to Volvulus ; abdomen with five external 
segments; antennae seven-jointed. Type, D. angustus , sp. n., 1. c. p. 78, 
pi. ii. fig. 16, Guatemala. 
Hemiosus, id. 1. c. p. 84. Allied to Berosus ; palpi short ; body beneath 
and femora with a peculiar silky opacity. Type, II. maculatus , sp. n., 
1. c. p. 85, pi. iii. fig. 2, Guatemala. 
Phcenonotum , id. 1. c. p. 97. To include Hydrophilus estriatus, Say, and 
P. dubium , Mexico, Guatemala, Costa Rica, apicale , Guatemala, Nicaragua, 
tarsale , fig. 8, Panama, p. 98, collars , Mexico, Guatemala, Icevicolle , 
Mexico, Guatemala, Nicaragua, p. 99, and rotundatum , fig. 9, Mexico, 
Guatemala, Panama, p. 100, pi. iii. : spp. nn. 
Cy cloty pus, id. 1. c. p. 100. Allied to Cyclonotum ; types, 0. godmani , 
pi. iii. fig. 10, Chiriqui, and latissimus, Choutales, spp. nn., pp. 100 & 101. 
Perochthes, id. 1. c. p. 101. Intermediate between Cyclonotum and 
Cercyon\ type, P. globulus , sp. n., 1. c. p. 102, pi. iii. fig. 11, Mexico, Gua- 
temala. 
Heteryon , id. 1. c. p. 103 ; type, II. depressus , sp. n., 7. c., Mexico. 
Nitidulodes , id. 1. c. p. 112. Allied to Pelosoma ; type, N. jansoni 
sp. n., 1. c. pi. iii. fig. 15, Chontales. 
Oosternum, id. 1. c. p. 112. Intermediate between Cercyon and Crypto - 
pleurum ; type, C. costatum , sp. n., 1. c. p. 113, pi. iii. fig. 16, Mexico, 
Guatemala, Nicaragua. 
Deltostethus , id. 1. c. p. 114. Between Oosternum and Cryptopleurum ; 
types, D. sulcatus, pi. iv. fig. 2, Guatemala, Panama, and palpalis, Chiri- 
qui, spp. nn., 1. c. pp. 114 & 115. 
