﻿The 
  British 
  Species 
  of 
  Andrena 
  and 
  Nomada. 
  223 
  

  

  of 
  dandelions 
  and 
  other 
  yellow 
  composites, 
  blackthorn, 
  

   the 
  white-flowered 
  Umbelliferae 
  and 
  the 
  bramble. 
  Other 
  

   flowers 
  will 
  be 
  mentioned 
  in 
  connection 
  with 
  the 
  different 
  

   species. 
  

  

  The 
  pairing 
  of 
  the 
  sexes 
  of 
  Andrena 
  is 
  often 
  noticed, 
  and 
  

   the 
  vast 
  numbers 
  of 
  males 
  that 
  one 
  sees 
  coursing 
  up 
  and 
  

   down 
  hedgerows 
  and 
  round 
  sunny 
  bushes 
  are 
  in 
  reality 
  

   searching 
  for 
  the 
  females. 
  When 
  one 
  of 
  these 
  ahghts, 
  a 
  

   collection 
  of 
  males 
  is 
  generally 
  quickly 
  attracted 
  to 
  the 
  

   particular 
  spot. 
  In 
  many 
  cases 
  these 
  males 
  will 
  fly 
  around, 
  

   often 
  within 
  a 
  few 
  inches 
  of 
  the 
  female 
  apparently 
  without 
  

   seeing 
  her, 
  and 
  it 
  would 
  seem 
  as 
  if 
  sight 
  played 
  but 
  a 
  small 
  

   part 
  in 
  the 
  matter. 
  Sometimes, 
  however, 
  she 
  is 
  perceived 
  

   and 
  pomiced 
  upon 
  almost 
  immediately. 
  With 
  species 
  that 
  

   form 
  compact 
  colonies 
  there 
  are 
  often 
  large 
  numbers 
  of 
  

   males 
  hovering 
  about 
  the 
  burrows 
  ready 
  to 
  seize 
  the 
  female 
  

   as 
  she 
  leaves 
  or 
  returns 
  to 
  the 
  nest. 
  The 
  females 
  of 
  some 
  

   species 
  seem 
  to 
  put 
  themselves 
  in 
  the 
  brightest 
  sunshine 
  on 
  

   some 
  broad 
  leaf 
  and 
  in 
  the 
  most 
  conspicuous 
  position 
  with 
  

   the 
  object 
  of 
  pairing, 
  but 
  others 
  I 
  have 
  observed 
  to 
  settle 
  

   on 
  a 
  branch 
  or 
  dead 
  leaf, 
  where 
  had 
  they 
  not 
  been 
  seen 
  to 
  

   ahght, 
  they 
  would 
  not 
  have 
  been 
  noticed 
  at 
  all. 
  Probably 
  

   pairing 
  sometimes 
  takes 
  place 
  in 
  the 
  burrows, 
  for 
  one 
  even- 
  

   ing 
  in 
  March 
  I 
  dug 
  out 
  a 
  number 
  of 
  males 
  and 
  females 
  of 
  

   A. 
  apicata, 
  and 
  although 
  it 
  was 
  almost 
  dark, 
  it 
  was 
  possible 
  

   to 
  see 
  that 
  in 
  several 
  cases 
  pairing 
  was 
  effected 
  at 
  once, 
  

   when 
  the 
  sexes 
  were 
  placed 
  together 
  in 
  glass-topped 
  boxes. 
  

   Pairing 
  of 
  individuals 
  of 
  distinct 
  but 
  closely 
  allied 
  species 
  

   must 
  be 
  very 
  rare, 
  as 
  I 
  have 
  never 
  seen 
  a 
  case, 
  though 
  I 
  

   have 
  spent 
  much 
  time 
  in 
  watching 
  the 
  pairings 
  of 
  A 
  . 
  wilkella, 
  

   afzeliella 
  and 
  similis, 
  where 
  these 
  all 
  occurred 
  in 
  company, 
  

   and 
  similarly 
  with 
  the 
  equally 
  closely 
  allied 
  species 
  of 
  the 
  

   trimmerana 
  group 
  and 
  the 
  small 
  bees 
  of 
  the 
  minutula 
  group. 
  

   Nor 
  have 
  I 
  ever 
  seen 
  a 
  specimen 
  that 
  I 
  should 
  consider 
  likely 
  

   to 
  be 
  a 
  hybrid. 
  Saunders 
  has 
  suggested 
  that 
  A. 
  praetexla 
  

   of 
  Smith 
  might 
  be 
  a 
  cross 
  between 
  carbonaria 
  and 
  bimacidata, 
  

   but 
  it 
  seems 
  to 
  me 
  to 
  be 
  merely 
  a 
  variety 
  of 
  the 
  former, 
  

   comparable 
  with 
  the 
  var. 
  consimilis 
  of 
  A. 
  nitida. 
  

  

  Variation 
  in 
  the 
  colour 
  of 
  the 
  pubescence 
  of 
  Andrena 
  is 
  

   considerable 
  in 
  some 
  species, 
  especially 
  in 
  the 
  substitution 
  

   of 
  brown 
  or 
  yellow 
  hairs 
  for 
  black 
  or 
  vice 
  versa, 
  while 
  in 
  

   a 
  few 
  cases 
  white 
  and 
  black 
  become 
  interchanged. 
  Of 
  

   course, 
  changes 
  due 
  to 
  fading 
  from 
  exposure 
  to 
  weather 
  are 
  

   not 
  to 
  be 
  reckoned 
  as 
  variation. 
  Few 
  of 
  these 
  variations 
  

  

  