HYDROPHILIDA. 763 
The large number of specimens received show some variation in connection with 
locality, the dark marks on the upper surface being remarkably extended in the small 
series from Tabasco; but there is nothing before me to connect the species with 
T. collaris. 
Tropisternus nitens (p. 56). 
To the localities given, add :—Britiso Honpuras, R. Hondo (Blancaneaux) ; Panama, 
near the city (Champion). 
9(a). Tropisternus sublevis. 
Hydrophilus sublevis, Lec. Proc. Ac. Phil. 1855, p. 368°. 
Hab. Nortu America, Nebraska and Georgia !.—Mexico, Northern Sonora (Mor- 
vtsON). 
11 (a). Tropisternus flavipalpis. 
Tropisternus flavipalpis, Sharp, Trans. Ent. Soc. Lond. 1883, p. 102°. 
Hab. Mexico (coll. Saunders) }. 
Tropisternus xanthopus (p. 59). 
To the Mexican localities given, add :—Paso del Norte and Santa Clara in Chihuahua, 
Durango city, Aguas calientes city (Hége). 
15 (a). Tropisternus dorsalis. 
Hydrophilus dorsalis, Brullé in Voy. d’Orb. vi. pt. 2, Ins. p. 57, t. 4. f. 6". 
Aydrophilus limbalis, Lec. Proc. Ac. Phil. 1865, p. 367”. 
Hab. Norta America, California ?.—MeExico, Mazatlan in Sinaloa (Hége), Rio 
Mescales (Buchan-Hepburn).—Soutn AMERICA 1. 
I think this insect will not prove to be distinct from H. lateralis; indeed, two or 
three of the examples found at Mazatlan are intermediate in colour, and this is the 
only character I know of to distinguish the two species. 
PLEURHOMUS (to follow Tropisternus, p. 61). 
Pleurhomus, Sharp, Trans. Ent. Soc. Lond. 18838, p. 114. 
This genus has been established to include a Brazilian insect, and one of our species 
formerly placed in Tropisternus. 
1, Pleurhomus obscurus. 
Tropisternus obscurus, huj. op. p. 60. 
To the locality given, add :—Mexico, Vera Cruz (Hoge). 
5 EE 2 
