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IX. On some aquatic Coleopter a from Ceylon. By David 

 Sharp, M.B., F.L.S., F.Z.S., &c. 



[Eead March 5th, 1890.] 



During a visit of a few months to Ceylon, in 1882, 

 Mr. George Lewis obtained an interesting collection of 

 Coleoptera, and placed the water-beetles in my hands 

 for determination. As the collection was a very frag- 

 mentary one and can include but a small proportion of 

 the aquatic Coleoptera that exist in the island, neither 

 Mr. Lewis nor myself anticipated that it would add much 

 to our knowledge of the fauna of the island. I have 

 however found on working through it, that the collection 

 includes a considerable proportion of novelties, and that 

 of the remainder a large part are species that have been 

 either very imperfectly described by Motschoulsky and 

 Walker, or that have not previously been known to occur 

 in the island. I have therefore drawn up a complete 

 list of the Dytiscidce and Hydrophilidce obtained by Mr. 

 Lewis, omitting only two or three specimens that are 

 representative of species requiring further materials for 

 their elucidation. I may mention that Mr. Lewis also 

 brought back a series of nine species of Gyrinidce, but as 

 all are described in Dr. Eegimbart's recent monograph 

 of the family, I have not thought it worth while to 

 include a list of them. 



Li dealing with the species that were so imperfectly 

 described by Walker in the Ann. & Mag. Nat. Hist., 

 1858 and 1859, I have followed the course advocated by 

 Mr. H. W. Bates, Ann. & Mag. Nat. Hist., January, 

 1886, that is to say, when the species have not in the 

 interim been described under other names I have given 

 a description, making use of Walker's proposed name. 

 But when the species has already been described under 

 another name, I have adopted this latter, as Walker's 

 descriptions are so brief, imperfect, and erroneous that 

 they can have no claim to priority. 



TRANS. ENT. SOC. LOND. 1890. — PAET II. (jUNE.) 



