﻿The 
  British 
  Species 
  of 
  Andrena 
  ami 
  Nomada. 
  279 
  

  

  of 
  our 
  species, 
  all 
  the 
  ^^ 
  have 
  a 
  strongly 
  elongated 
  3rd 
  

   antennal 
  joint 
  (as 
  compared 
  with 
  the 
  4th), 
  this 
  rarely 
  being 
  

   less 
  than 
  twice 
  as 
  long 
  as 
  the 
  latter, 
  and 
  sometimes 
  as 
  

   much 
  as 
  three 
  times 
  the 
  length. 
  

  

  A. 
  chrysosceles 
  and 
  nitidiuscula 
  are 
  representatives 
  of 
  a 
  

   well-marked 
  group. 
  The 
  head 
  of 
  the 
  (^ 
  is 
  deeply 
  emarginate 
  

   behind, 
  so 
  that 
  the 
  lower 
  occipital 
  angles 
  (seen 
  from 
  above) 
  

   are 
  quite 
  strongly 
  produced, 
  the 
  mandibles 
  are 
  rather 
  long 
  

   and 
  form 
  a 
  distinct 
  cross 
  at 
  the 
  tips. 
  The 
  clypeus 
  is 
  re- 
  

   markable 
  in 
  having 
  a 
  much 
  more 
  widely 
  upturned 
  apical 
  

   margin 
  than 
  is 
  normal 
  in 
  the 
  genus. 
  This 
  is 
  best 
  seen 
  

   when 
  it 
  is 
  viewed 
  from 
  the 
  base. 
  The 
  tubercle 
  of 
  the 
  

   labrum 
  is 
  ordinary. 
  Propodeum 
  above 
  sparsely 
  clothed, 
  

   so 
  that 
  not 
  only 
  on 
  the 
  anterior 
  area 
  but 
  on 
  a 
  large 
  space 
  

   on 
  each 
  side 
  the 
  sculpture 
  is 
  easily 
  seen. 
  Scutellum 
  with 
  

   sparse 
  or 
  at 
  least 
  remote 
  punctures, 
  not 
  very 
  convex, 
  

   rugulose 
  all 
  over 
  ; 
  abdomen 
  with 
  the 
  general 
  clothing 
  con- 
  

   sisting 
  of 
  only 
  very 
  short 
  hairs, 
  shining 
  and 
  to 
  the 
  naked 
  

   eye 
  appearing 
  nearly 
  bare, 
  the 
  basal 
  segment 
  polished. 
  

   Intermediate 
  ventral 
  segments 
  with 
  extremely 
  dense 
  

   specialised 
  ciliation 
  on 
  their 
  apical 
  margins. 
  Genital 
  

   armature 
  with 
  the 
  lobes 
  of 
  the 
  stipites 
  much 
  rounded 
  off 
  

   at 
  the 
  angles, 
  short 
  or 
  subglobose 
  ; 
  sagittae 
  expanded 
  by 
  

   rounding 
  of 
  the 
  sides. 
  Female 
  in 
  general 
  characters 
  like 
  

   the 
  (^, 
  the 
  apical 
  white 
  fringes 
  of 
  the 
  dorsal 
  segments 
  form- 
  

   ing 
  a 
  more 
  conspicuous 
  pattern 
  of 
  bands 
  or 
  lateral 
  streaks. 
  

   Pygidial 
  area 
  without 
  a 
  sharply 
  raised 
  median 
  triangular 
  

   area. 
  Floccus 
  imperfect, 
  the 
  hairs 
  of 
  the 
  basal 
  portion 
  of 
  

   the 
  trochanter 
  comparatively 
  short 
  and 
  little 
  curved. 
  

  

  A. 
  coitana 
  and 
  tarsata. 
  In 
  general 
  facies, 
  and 
  in 
  the. 
  

   greatly 
  and 
  somewhat 
  sharply 
  produced 
  inner 
  apical 
  angles 
  

   of 
  the 
  lobes 
  of 
  the 
  stipites, 
  as 
  well 
  as 
  in 
  the 
  long 
  hairs 
  that 
  

   clothe 
  the 
  ventral 
  abdominal 
  segments, 
  a 
  very 
  dense 
  and 
  

   highly 
  specialised 
  apical 
  ciUation 
  being 
  absent, 
  these 
  

   species 
  resemble 
  each 
  other 
  and 
  are 
  more 
  closely 
  allied 
  to 
  

   one 
  another, 
  than 
  is 
  either 
  to 
  any 
  other 
  species. 
  

   ■ 
  The 
  following 
  great 
  differences 
  are 
  notable 
  in 
  the 
  males. 
  

   In 
  tarsata 
  the 
  clypeus 
  is 
  somewhat 
  widely 
  margined, 
  as 
  

   in 
  chrysosceles, 
  the 
  tubercle 
  of 
  the 
  labrum 
  is 
  upturned, 
  

   but 
  does 
  not 
  rise 
  above 
  the 
  curved 
  apical 
  margin 
  of 
  the 
  

   clypeus, 
  the 
  mandibles 
  are 
  rather 
  short 
  and 
  wide 
  and 
  

   repose 
  one 
  on 
  the 
  other, 
  while 
  the 
  hind 
  tibiae 
  are 
  more 
  

   than 
  usually 
  wide 
  or 
  thick. 
  In 
  coitana 
  the 
  clypeus 
  is 
  very 
  

   narrowly 
  margined, 
  the 
  tubercle 
  of 
  the 
  labrum 
  ordinary, 
  

  

  