﻿The 
  British 
  Species 
  of 
  Andrena 
  and 
  Nomada. 
  247 
  

  

  discovered 
  in 
  others. 
  The 
  few 
  recent 
  examples 
  that 
  I 
  have 
  

   seen 
  have 
  all 
  been 
  taken 
  casually, 
  so 
  to 
  speak, 
  by 
  those 
  

   interested 
  in 
  Orders 
  other 
  than 
  Hymenoptera, 
  and 
  all 
  were 
  

   single 
  specimens. 
  These 
  were 
  from 
  Hants 
  (on 
  two 
  occa- 
  

   sions), 
  Berks 
  and 
  Cornwall. 
  It 
  occurs 
  in 
  May 
  and 
  June, 
  

   and 
  may 
  be 
  expected 
  to 
  visit 
  yellow 
  Composites, 
  as 
  one 
  

   examined 
  by 
  me 
  contained 
  this 
  pollen 
  on 
  its 
  legs. 
  It 
  is 
  

   not 
  known 
  whether 
  any 
  Nomada 
  is 
  attached 
  to 
  this 
  species, 
  

   but 
  it 
  has 
  been 
  found 
  stylopised. 
  

  

  A. 
  bucephala 
  is 
  another 
  extremely 
  local 
  species, 
  also 
  of 
  

   wide 
  distribution 
  in 
  the 
  southern 
  counties, 
  and 
  found 
  by 
  

   Hallett 
  in 
  Glamorganshire 
  in 
  Wales. 
  It 
  was 
  once 
  very 
  

   abundant 
  at 
  Hampstead, 
  and 
  was 
  found 
  also 
  at 
  Bristol 
  

   and 
  in 
  Hampshire. 
  It 
  has 
  been 
  taken 
  in 
  several 
  localities 
  

   in 
  Surrey, 
  in 
  Kent, 
  at 
  Birmingham, 
  and 
  occurs 
  also 
  in 
  

   Devonshire 
  and 
  Cornwall. 
  This 
  bee 
  is 
  partial 
  to 
  the 
  flowers 
  

   of 
  blackthorn, 
  and 
  has 
  also 
  been 
  taken 
  on 
  holly 
  and 
  

   Viburnum. 
  

  

  From 
  the 
  form 
  of 
  its 
  pollinigerous 
  apparatus 
  one 
  would 
  

   expect 
  it 
  to 
  visit 
  such 
  flowers 
  as 
  are 
  favourites 
  with 
  the 
  

   common 
  A. 
  irimmerana. 
  Nomada 
  bucephalae 
  is 
  its 
  peculiar 
  

   parasite, 
  and 
  has 
  been 
  erroneously 
  considered 
  a 
  mere 
  

   variety 
  of 
  ruficornis 
  by 
  some 
  authors 
  ; 
  while 
  Smith 
  and 
  

   Shuckard 
  considered 
  it 
  to 
  be 
  Panzer's 
  lateralis, 
  which 
  is 
  

   also 
  an 
  error. 
  This 
  parasite 
  probably 
  occurs 
  in 
  all 
  locaUties 
  

   where 
  its 
  host 
  is 
  properly 
  established, 
  for 
  it 
  formerly 
  

   abounded 
  on 
  Hampstead 
  Heath, 
  and 
  is 
  found 
  with 
  it 
  in 
  

   Surrey, 
  Devon 
  and 
  Glamorgan. 
  Stylopised 
  bucephala 
  occur, 
  

   as 
  I 
  have 
  a 
  (^ 
  and 
  $ 
  so 
  affected. 
  

  

  All 
  the 
  colonies 
  of 
  this 
  Andrena 
  that 
  I 
  have 
  seen 
  have 
  

   had 
  only 
  a 
  single 
  entrance. 
  Into 
  this 
  one 
  may 
  see 
  dozens 
  

   of 
  heavily 
  laden 
  females 
  enter, 
  when 
  they 
  are 
  storing 
  their 
  

   pollen, 
  and 
  it 
  is 
  to 
  be 
  presumed 
  that 
  separate 
  tubes 
  will 
  be 
  

   found 
  to 
  be 
  excavated 
  from 
  the 
  common 
  hole, 
  by 
  which 
  all 
  

   enter. 
  Under 
  special 
  circumstances 
  some 
  other 
  species 
  

   show 
  some 
  approximation 
  to 
  the 
  habits 
  of 
  bucephala. 
  

   Twice 
  Nomada 
  alternata 
  has 
  been 
  seen 
  to 
  enter 
  or 
  issue 
  

   from 
  the 
  burrow 
  of 
  bucephala, 
  and 
  once 
  a 
  female 
  trimtnerana 
  

   entered 
  the 
  same, 
  so 
  that 
  it 
  is 
  not 
  certain 
  that 
  this 
  Nomada 
  

   is 
  parasitic 
  on 
  the 
  former 
  as 
  it 
  is 
  on 
  the 
  latter. 
  

  

  We 
  now 
  come 
  to 
  the 
  group 
  of 
  Andrena 
  varians. 
  

  

  A. 
  clarkella 
  is 
  a 
  local 
  bee, 
  but 
  of 
  extremely 
  wide 
  distribu- 
  

   tion, 
  and 
  appears 
  as 
  early 
  in 
  the 
  year 
  as 
  any 
  of 
  our 
  bees. 
  

   It 
  is 
  often 
  common 
  in 
  Scotch 
  localities 
  and 
  in 
  the 
  north 
  of 
  

  

  