included in the genus Tropisternus. 117 



H. limbatus, Brulle, Voy. d'Orb., p. 56. Brazil. — Bridle 

 seems certainly to have described the Fabrician H. 

 lateralis over again under this name, which (unless 

 some one shall point out characters to distinguish the 

 varieties of H. lateralis as distinct species) must fall into 

 synonymy. 



Tropisternus mergus, Bedt., Hug. Kasch., iv., 2, p. 514. 

 Hindostan. — As the genus Tropisternus is exclusively 

 South American, there is clearly some error in assigning 

 this species to it, and I have therefore not occupied 

 myself with it. 



T. nitidus, Cast., Hist. Nat., ii., p. 53. Guadeloupe. 

 — This is, I consider, a synonym of the same author's 

 T. chalybeus : the dozen words of description do not in- 

 dicate any distinction. 



Hydrophilus quadristriatus, Horn, Trans. Am. Ent. 

 Soc, 1871, p. 331. — This has already been recorded by 

 its author as a synonym of H. sublcevis, Lee. 



Tropisternus sellatus, Cast., /. c, p. 54. — For the present 

 this must remain a doubtful species ; the description 

 may possibly refer to an individual of H. collaris, dis- 

 coloured by decay. 



Hydrophilus setiger, Germ., Ins. Spec. Nov., p. 95. 

 Buenos Ayres. — This cannot with certainty be identified 

 from the description, which consists almost entirely of 

 characters common to the whole of the genus. The 

 expression " thoracis lateribus fulvis " seems to be quite 

 exceptional, but may perhaps refer to the infiexed margin, 

 which is yellowish or fulvescent in numerous species. 



