54 HYDROPHILIDA. 
HYDROPHILUS. 
Hydrophilus, Geoffroy, Ins. Par. i. p. 180. 
Hydrous, Leach, Zool. Mise. iii. p. 92. 
This genus comprises about forty species, and has a wide distribution in both the 
eastern and western hemispheres. 
1. Hydrophilus insularis. (Tab. II. fig. 1.) 
Hy drophilus insularis, Cast. Hist. Nat. ii. p. 50°. 
Hydrophilus pilatei, Dupt. in litt. 
Hab. Nortn America, Texas, California.—Mexico, Misantla (Hoge), Puebla, Yucatan 
(Sallé), Presidio (Forrer); GuatemMaLa, San Gerénimo (Champion).—ANTILLES 4, Cuba }, 
Guadaloupe}. 
The figure represents a specimen from Misantla. 
2. Hydrophilus triangularis. 
Hydrophilus triangularis, Say, Journ. Ac. Phil. iii. p. 201°; Lec. Proc. Ac. Phil. 1855, p. 367°. 
Hab. Nortn America, from New York? to California 2,—Mexico, Misantla (Hoge), 
Parada (Sailé), San Luis Potosi (Dr. Palmer). 
3. Hydrophilus ater. 
Hy drophilus ater, Fabr. Ent. Syst. i. p. 183°; Oliv. Ent. ii. 39, p. 10, t. 2. f. 6°. 
Hydrophilus brasiliensis, Cast. Et. Ent. p. 50°; Hist. Nat. ii. p. 50%. 
Hab. Nortu America, Philadelphia, Texas.—Mexico, Misantla, Vera Cruz (Hoge), 
Orizaba (Sallé) ; GuaTeMALA, Paso Antonio 400 feet (Champion) ; Nicaragua, Chontales 
(Belt, Janson) ; Costa Rica (van Patten).—AntiLLES, Cuba ; Sourn America !, Colombia, 
Cayenne, Brazil+, Bahia. | 
A species so largely distributed as is this one is sure to show some variation ; and in 
the equatorial region the individuals of this species appear to be usually larger and 
broader than they are more to the north; the northern specimens usually have the 
sternal spine rather shorter than those from the south: but these slight characters are very 
variable. The Central-American specimens always have the apices of the wing-cases 
quite without acumination ; but in the South-American individuals it is usually found 
(when the elytra are made to gape a little) that each extremity at the suture is slightly 
emarginate inwardly, so that there is a very minute sharp angle: but this small 
character is likewise a variable one. 
. TROPISTERN US. 
Tropisternus, Solier, Ann. Soc. Ent. Fr. 1834, p. 308. 
This is a genus characteristic of the New World, where it has a very wide distribu- 
