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  VII. 
  The 
  British 
  Species 
  of 
  Andrena 
  and 
  Nomada. 
  By 
  

   R. 
  C. 
  L. 
  Perkins, 
  M.A., 
  D.Sc. 
  

  

  [Read 
  May 
  7th, 
  1919.] 
  

  

  Plates 
  XI— 
  XV 
  

  

  The 
  species 
  of 
  the 
  genus 
  Andrena 
  and 
  its 
  parasites 
  of 
  the 
  

   genus 
  Nomada 
  have 
  perhaps 
  been 
  more 
  sought 
  after 
  and 
  

   collected 
  than 
  any 
  other 
  of 
  our 
  Aculeate 
  Hymenoptera. 
  

   This 
  is 
  probably 
  due 
  to 
  the 
  fact 
  that 
  in 
  our 
  limited 
  fauna 
  

   they 
  present 
  a 
  good 
  appearance 
  in 
  a 
  collection, 
  few 
  being 
  

   of 
  small 
  size 
  and 
  many 
  of 
  considerable 
  beauty, 
  while 
  at 
  the 
  

   same 
  time 
  hardly 
  any 
  places 
  are 
  so 
  poor 
  as 
  not 
  to 
  possess 
  

   some 
  local 
  and 
  interesting 
  species. 
  Andrena 
  is 
  a 
  genus 
  of 
  

   enormous 
  extent, 
  our 
  sixty-one 
  species 
  being 
  a 
  small 
  fraction 
  

   of 
  those 
  that 
  exist, 
  or, 
  indeed, 
  of 
  those 
  that 
  have 
  been 
  

   already 
  collected. 
  Unfortunately, 
  no 
  one 
  has 
  yet 
  been 
  

   found 
  to 
  classify 
  the 
  species 
  as 
  a 
  whole, 
  and 
  no 
  satisfactory 
  

   grouping 
  even 
  of 
  the 
  European 
  forms 
  has 
  yet 
  been 
  achieved. 
  

   The 
  various 
  arrangements 
  that 
  have 
  been 
  proposed 
  for 
  

   our 
  British 
  species 
  all 
  leave 
  something 
  to 
  be 
  desired. 
  Those 
  

   adopted 
  by 
  F. 
  Smith 
  and 
  Shuckard 
  are 
  quite 
  impossible 
  

   and 
  unnatural, 
  being 
  based 
  on 
  superficial 
  appearances. 
  

   The 
  classij&cation 
  used 
  in 
  the 
  works 
  of 
  Edward 
  Saunders 
  

   was 
  a 
  vast 
  improvement 
  on 
  these, 
  especially 
  that 
  in 
  his 
  last 
  

   book. 
  Schmiedeknecht's 
  arrangement 
  in 
  the 
  " 
  Apidae 
  

   Europaeae 
  " 
  is 
  often 
  misatisfactory. 
  But 
  before 
  consider- 
  

   ing 
  in 
  detail 
  the 
  arrangement 
  in 
  groups 
  of 
  our 
  British 
  

   species, 
  some 
  notes 
  on 
  the 
  habits 
  of 
  the 
  species 
  and 
  their 
  

   parasites 
  may 
  be 
  given. 
  Smith, 
  Saunders 
  and 
  Shuckard 
  

   have 
  all 
  described 
  these 
  to 
  some 
  extent. 
  All 
  these 
  collectors 
  

   had 
  constant 
  access 
  to 
  some 
  of 
  the 
  finest 
  collecting 
  grounds 
  

   that 
  are 
  to 
  be 
  found 
  in 
  the 
  South 
  of 
  England, 
  and 
  conse- 
  

   quently 
  there 
  is 
  a 
  tendency, 
  I 
  think, 
  in 
  their 
  writings 
  to 
  

   consider 
  species 
  that 
  are 
  really 
  quite 
  local 
  to 
  be 
  of 
  more 
  

   general 
  distribution 
  than 
  they 
  actually 
  are. 
  As 
  a 
  beginner 
  

   it 
  was 
  my 
  lot 
  to 
  collect 
  in 
  a 
  district 
  where 
  a 
  sandy 
  soil- 
  — 
  so 
  

   attractive 
  to 
  most 
  Aculeata 
  — 
  was 
  wanting, 
  and 
  in 
  conse- 
  

   quence 
  it 
  was 
  years 
  before 
  I 
  met 
  with 
  living 
  specimens 
  of 
  

  

  TRANS. 
  ENT. 
  SOC. 
  LOND. 
  1919. 
  — 
  PARTS 
  I, 
  II. 
  (jXJLy) 
  

  

  