﻿The 
  British 
  Species 
  of 
  Andrena 
  and 
  Nomada. 
  277 
  

  

  resembling 
  it 
  in 
  all 
  important 
  characters 
  occur 
  in 
  Europe 
  

   and 
  N. 
  America, 
  and 
  probably 
  elsewhere. 
  At 
  first 
  sight 
  

   the 
  male 
  is 
  a 
  commonplace 
  and 
  obscure 
  insect, 
  not 
  in- 
  

   frequently 
  confused 
  with 
  other 
  species 
  in 
  collections. 
  It 
  

   has 
  most 
  of 
  the 
  characters 
  of 
  the 
  typical 
  males 
  of 
  the 
  

   ivilkella 
  group, 
  but 
  the 
  1st 
  segment 
  is 
  sometimes 
  quite 
  

   shining, 
  varying 
  in 
  different 
  individuals, 
  as 
  does 
  the 
  

   puncturation, 
  and 
  the 
  colour 
  of 
  the 
  facial 
  hairs 
  and 
  legs. 
  

   It 
  is 
  remarkable 
  for 
  the 
  long 
  slender 
  hind 
  tarsi 
  and 
  rather 
  

   thick 
  hind 
  tibiae, 
  the 
  whole 
  length 
  of 
  the 
  tarsi 
  (excluding 
  

   the 
  pulvillus 
  and 
  claws) 
  being 
  not 
  less 
  than 
  1| 
  times 
  the 
  

   length 
  of 
  the 
  tibiae, 
  whereas 
  in 
  the 
  c^ 
  (J 
  of 
  other 
  members 
  

   of 
  the 
  group 
  the 
  tibiae 
  are 
  normal 
  and 
  the 
  tarsi 
  are 
  not 
  

   1| 
  times 
  their 
  length. 
  The 
  female 
  is 
  quite 
  peculiar 
  in 
  its 
  

   poUinigerous 
  organs, 
  though 
  otherwise 
  exhibiting 
  the 
  

   normal 
  wilkella 
  characters. 
  The 
  hairs 
  of 
  the 
  propodeum 
  

   are 
  very 
  long, 
  plumose 
  and 
  strongly 
  curved 
  so 
  that 
  they 
  

   form 
  a 
  pollen-basket 
  almost 
  completely 
  closed 
  in, 
  the 
  hind 
  

   tibiae 
  are 
  strongly 
  clavate, 
  being 
  very 
  wide 
  at 
  the 
  apex 
  

   and 
  with 
  a 
  very 
  short 
  fringe 
  formed 
  by 
  the 
  scopa 
  on 
  their 
  

   upper 
  edge; 
  on 
  the 
  outer 
  side 
  the 
  scopal 
  hairs 
  are 
  fine, 
  

   so 
  that 
  the 
  dense 
  puncturation 
  of 
  the 
  tibia 
  is 
  easily 
  seen 
  

   beneath 
  them; 
  the 
  hairs 
  of 
  the 
  lower 
  margin 
  are 
  com- 
  

   paratively 
  little 
  curved 
  upwards 
  over 
  this 
  surface. 
  The 
  

   floccus 
  is 
  decidedly 
  imperfect, 
  the 
  hairs 
  on 
  the 
  basal 
  portion 
  

   of 
  the 
  trochanter 
  being 
  much 
  less 
  curved 
  and 
  thicker 
  and 
  

   less 
  plumose 
  than 
  those 
  on 
  the 
  apical. 
  

  

  Group 
  of 
  A. 
  NANA. 
  

  

  With 
  one 
  exception 
  all 
  of 
  this 
  group 
  are 
  minute 
  in 
  size, 
  

   only 
  one 
  or 
  two 
  of 
  our 
  other 
  species 
  approaching 
  them 
  so 
  

   closely 
  in 
  this 
  respect 
  that 
  they 
  could 
  be 
  mistaken. 
  

   Clearly 
  the 
  group 
  itself 
  is 
  closely 
  allied 
  to 
  the 
  preceding 
  

   one. 
  

  

  The 
  males 
  have 
  short 
  mandibles 
  closing 
  one 
  on 
  the 
  

   other, 
  and 
  no 
  peculiarities 
  of 
  the 
  head 
  or 
  labrum. 
  The 
  3rd 
  

   joint 
  of 
  the 
  antennae 
  is 
  never 
  greatly 
  elongated, 
  though 
  

   distinctly 
  longer 
  than 
  its 
  apical 
  width, 
  longer 
  too 
  than 
  the 
  

   4th 
  which 
  is 
  generally 
  wider 
  than 
  long, 
  rarely 
  about 
  square 
  

   in 
  outline. 
  The 
  propodeum 
  is 
  unusually 
  bare 
  above 
  

   though 
  hairy 
  at 
  the 
  sides, 
  so 
  that 
  not 
  only 
  the 
  anterior 
  

   area 
  is 
  glabrous 
  but 
  the 
  parts 
  adjoining 
  this 
  are 
  only 
  

   shghtly 
  less 
  exposed 
  to 
  view. 
  The 
  basal 
  abdominal 
  seg- 
  

  

  