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III. The Wsitev beetles of Japan. 
By David Sharp, M.B. 
[Read 6th January, 1873.] 
My object in this paper is to enumerate the species of 
Dytiscida? and Hydrophilidse found by Mr. George Lewis 
in Japan. To enable me to do this Mr. Lewis has en- 
trusted me \^dth the whole of the specimens belonging to 
these families, captured by him during his residence in the 
Japanese islands. To the students of the European fauna 
these Japanese insects are of very great interest: the 
number of species common to Europe and these far distant 
islands is by no means inconsiderable ; other European 
species are represented in Japan by closely allied forms, 
and some of our larger genera possess there numerous 
species. Mingled with these European forms we find a 
large proportion of quite Eastern genera and species. It 
must be remembered that we know comparatively little of 
the beetles of central and eastern Asia, especially of those 
parts contiguous to the Japanese islands, so that at present 
we are not in a position to form any correct opinion as to 
what proportion the European forms bear to the eastern 
ones in these parts. It will probably, however, ultimately 
be found that the faunas of the eastern and western portions 
of the old world gradually merge into one another, and 
should really be considered but as one fauna. The species 
here enumerated belong to twenty-five genera, of which 
three are unrepresented in the European or Mediterranean 
fauna ; these three are all genera of a wide distribution. 
Dytiscid^e. 
I. Cyhister japonicus, n. sp. Sat convexus, latior, 
ovalis postice dilatatus, supra nigro - olivaceus, capite 
antice, prothoracis lateribus, vittaque longitudinali versus 
elytrorum marginem testaceis ; subtus testaceus, pectore 
medio late olivaceo, suturis, abdominisque segmentis an- 
guste nigro-marginatis. 
Long. 18 lin. ; lat. 9|— 10 lin. ; alt. 51 lin. 
Mas, prothorace elytrisque Igevibus. 
Fem., prothorace reticulato-strigoso, elytris excepte ad 
apicem reticulato-striatis. 
TRANS. ENT. SOC. 1873. PART I. (MAR. ) 
