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XXII. Revision of the Hydrophilidse of Neiv Zealand. 

 By Da.vid Sharp. 



[Eead September 3rcl, 1884.] 



I HAVE recently submitted the New Zealand specimens 

 of Hydrophilidce in my collection to an examination with 

 a view to determining the species and throwing some 

 light on their classification. As the result I find I have 

 twenty-four species which I am obliged to refer to twelve 

 genera ; five of these genera — Hydrobius, Paracymus, 

 Torniis, Cyclonotum, and Cercyon — are each represented 

 only by a single species, and of these five genera 

 no less than four are found in other countries, the 

 species in New Zealand being the same as that found 

 abroad. Cercyon is represented by an introduced 

 European species ; Hydrobius, Paracymus, and Cyclo- 

 notum each by an Australian species ; while Tornus at 

 present seems likely to be a peculiar endemic New Zea- 

 land form. Of the other seven genera no less than six 

 are peculiar to New Zealand, so far as we at present 

 know, while the cosmopolitan genus Philydrus is repre- 

 sented by three species. This result is very remark- 

 able, for the genera of Hydropliilidce are, as a rule, very 

 widely distributed ; and, if we consider also that some 

 of the most cosmopolitan genera of the family are quite 

 unrepresented in the fauna, we cannot but admit that 

 the New Zealand fauna of Hydrophilidce is, as a whole, 

 of the most remarkable character. The genera Ilydro- 

 philus, Berosus, Hydrochus, and Octhebius, all of which 

 are nearly cosmopolitan, and all found in Australia, 

 may be mentioned as examples of forms we should 

 expect to find in New Zealand, but which apparently are 

 absent. 



The Hydrophilidce are insects of an unattractive cha- 

 racter, and usually of inactive and retiring habits, and 

 it may be taken as certain that there exist in the country 

 numerous species with which I am unacquainted, and 

 which, when known, may modify the opinion I have just 



TRANS. ENT. SOC. LOND. 1884. — PART IV. (DEC.) 



