﻿Mr. 
  G. 
  R. 
  Waterhouse 
  on 
  Hydrochus, 
  ^c. 
  229 
  

  

  XXIV. 
  A 
  Revision 
  of 
  the 
  Synonymy 
  of 
  the 
  British 
  Species 
  

   of 
  the 
  Coleopterous 
  Genera 
  Hydrochus 
  and 
  Ochthebius. 
  

   By 
  G. 
  R. 
  Waterhouse, 
  Esq., 
  F.Z.S. 
  

  

  [Read 
  4lh 
  April, 
  1853.] 
  

  

  The 
  acquisition 
  of 
  Mr. 
  Stephens's 
  Collection 
  by 
  the 
  British 
  Mu- 
  

   seum, 
  where 
  the 
  specimens 
  may 
  always 
  be 
  examined, 
  has 
  furnished 
  

   a 
  favourable 
  opportunity 
  to 
  British 
  Entomologists 
  to 
  clear 
  up 
  the 
  

   synononiy 
  of 
  the 
  insects 
  of 
  their 
  own 
  country, 
  since 
  that 
  Collection 
  

   is, 
  on 
  the 
  whole, 
  the 
  most 
  perfect 
  that 
  has 
  hitherto 
  been 
  formed, 
  

   and 
  contains 
  the 
  types 
  of 
  tlie 
  species 
  described 
  by 
  its 
  late 
  owner, 
  

   as 
  well 
  as 
  the 
  types 
  described 
  by 
  Marsham. 
  Furthermore, 
  the 
  

   general 
  Collection 
  of 
  the 
  British 
  Museum 
  possesses 
  specimens 
  

   of 
  European 
  species, 
  forwarded, 
  with 
  names, 
  from 
  various 
  parts 
  of 
  

   the 
  Continent, 
  and 
  hence 
  these 
  continental 
  specimens 
  can 
  be 
  com- 
  

   pared 
  with 
  the 
  British. 
  

  

  A 
  short 
  time 
  since 
  I 
  determined 
  to 
  re-examine 
  some 
  of 
  the 
  

   groups 
  of 
  small 
  Coleoptera 
  of 
  my 
  own 
  English 
  Collection, 
  and 
  to 
  

   determine, 
  if 
  possible, 
  the 
  nomenclature 
  of 
  the 
  species, 
  according 
  

   to 
  the 
  French 
  and 
  German 
  Entomologists, 
  taking 
  Gyllenhal, 
  

   Erichson 
  and 
  Mulsant 
  as 
  my 
  chief 
  guides. 
  

  

  I 
  have 
  now 
  completed 
  the 
  examination 
  of 
  the 
  species 
  of 
  Ochthe- 
  

   bius, 
  Hydrcena, 
  Hydrochus, 
  and 
  Cercyon, 
  and 
  I 
  believe 
  I 
  have 
  

   satisfactorily 
  determined 
  the 
  species 
  of 
  these 
  genera, 
  so 
  far 
  as 
  the 
  

   authors 
  above 
  mentioned 
  are 
  concerned 
  ; 
  and 
  with 
  regard 
  to 
  the 
  

   genera 
  Ochthebius 
  and 
  Hydrochus, 
  I 
  have 
  also 
  examined 
  the 
  species 
  

   of 
  Mr. 
  Stephens's 
  Collection, 
  and 
  have 
  prepared 
  a 
  list 
  of 
  the 
  species 
  

   to 
  lay 
  before 
  the 
  Society 
  this 
  evening. 
  The 
  other 
  genera 
  I 
  pro- 
  

   pose 
  to 
  bring 
  before 
  your 
  notice 
  upon 
  an 
  early 
  occasion. 
  

  

  As 
  regards 
  the 
  genus 
  Hydrochus 
  little 
  need 
  be 
  said. 
  I 
  have 
  

   long 
  imagined 
  we 
  had 
  but 
  two 
  species 
  in 
  England, 
  — 
  I 
  had 
  but 
  two 
  

   sjiecies 
  in 
  my 
  own 
  Collection, 
  and 
  upon 
  examining 
  a 
  specimen, 
  or 
  

   specimens, 
  in 
  Mr. 
  Stephens's 
  Collection, 
  of 
  the 
  third 
  species, 
  I 
  

   could 
  perceive 
  no 
  points 
  of 
  distinction. 
  This 
  1 
  now 
  find 
  is 
  easily 
  

   explained. 
  We 
  have 
  in 
  fact 
  three 
  British 
  species, 
  viz. 
  : 
  — 
  

  

  1. 
  Hydrochus 
  brevis, 
  of 
  German, 
  French, 
  and 
  English 
  authors. 
  

  

  2. 
  Hydrochus 
  elongatus, 
  also 
  of 
  Continental 
  and 
  English 
  

  

  authors; 
  but 
  Mr. 
  Stephens 
  I 
  find 
  has, 
  under 
  this 
  name, 
  

  

  