﻿278 
  Mr. 
  R. 
  C. 
  L. 
  Perkins 
  on 
  

  

  ment 
  is 
  minutely 
  rugulose 
  under 
  a 
  strong 
  lens 
  (except 
  

   in 
  one 
  species), 
  and 
  the 
  second, 
  except 
  at 
  the 
  sides, 
  is 
  bare 
  

   except 
  for 
  the 
  presence 
  of 
  very 
  short 
  hairs. 
  In 
  some 
  of 
  

   the 
  species 
  the 
  anterior 
  area 
  of 
  the 
  propodeum 
  is 
  distinctly 
  

   and 
  densely 
  rugose 
  over 
  its 
  whole 
  surface. 
  The 
  clypeus 
  

   is 
  never 
  white 
  or 
  yellow, 
  though 
  often 
  clothed 
  with 
  white 
  

   hairs. 
  

  

  It 
  should 
  be 
  impossible 
  to 
  mistake 
  the 
  S 
  ^ 
  oi 
  the 
  minute 
  

   species 
  of 
  this 
  group 
  for 
  those 
  of 
  any 
  other, 
  because 
  of 
  the 
  

   latter 
  any 
  the 
  least 
  liable 
  to 
  be 
  confused 
  either 
  have 
  a 
  

   white 
  clypeus 
  or 
  else 
  the 
  mandibles 
  form 
  a 
  slight 
  cross 
  

   at 
  the 
  apex. 
  As 
  to 
  the 
  one 
  larger 
  species 
  (proxima), 
  its 
  

   w^ell-exposed 
  propodeum 
  with 
  the 
  anterior 
  area 
  densely 
  

   and 
  distinctly 
  rugose 
  right 
  up 
  to 
  the 
  posterior 
  declivity, 
  

   combined 
  with 
  the 
  subglabrous 
  abdomen, 
  which 
  has 
  

   white 
  apical 
  lateral 
  streaks 
  on 
  the 
  intermediate 
  segments, 
  

   gives 
  it 
  a 
  most 
  distinct 
  appearance. 
  

  

  The 
  females 
  resemble 
  miniatures 
  of 
  the 
  ivilkeUa 
  group, 
  

   but 
  are 
  at 
  once 
  separable 
  by 
  the 
  thin 
  and 
  imperfect 
  floccus. 
  

  

  From 
  small 
  species 
  in 
  other 
  groups 
  the 
  rugulose 
  abdomen, 
  

   not 
  polished 
  on 
  the 
  basal 
  segment, 
  separates 
  most 
  of 
  these 
  

   females, 
  or 
  if 
  this 
  is 
  polished, 
  the 
  area 
  of 
  the 
  propodeum 
  

   is 
  distinctly 
  rugose 
  to 
  the 
  declivity. 
  The 
  hind 
  tibiae 
  are 
  

   black 
  (sometimes 
  paUid 
  from 
  immaturity), 
  the 
  scopae 
  

   never 
  conspicuously 
  yellow. 
  

  

  Group 
  of 
  species 
  with 
  white 
  clypeus 
  in 
  the 
  males 
  

   together 
  with 
  A. 
  nitidiuscula. 
  

  

  This 
  is 
  not 
  a 
  natural 
  group 
  as 
  compared 
  with 
  the 
  others, 
  

   but, 
  as 
  said 
  already, 
  in 
  our 
  small 
  fauna 
  it 
  is 
  convenient 
  

   to 
  keep 
  the 
  species 
  together. 
  In 
  my 
  opinion 
  the 
  Andrenas 
  

   with 
  a 
  white 
  clypeus 
  are 
  primitive 
  forms, 
  some 
  of 
  which 
  

   have 
  given 
  rise 
  to 
  groups 
  of 
  species 
  with 
  the 
  ordinary 
  

   black 
  clypeus. 
  We 
  have 
  not 
  even 
  a 
  pair 
  of 
  species 
  in 
  this 
  

   group 
  which 
  can 
  be 
  said 
  to 
  be 
  very 
  closely 
  allied, 
  the 
  white- 
  

   faced 
  chrysosceles 
  and 
  black-faced 
  nitidiuscula 
  alone 
  being 
  

   comparatively 
  nearly 
  related 
  to 
  one 
  another. 
  A. 
  analis 
  

   bears 
  to 
  A. 
  coif 
  ana 
  somewhat 
  the 
  same 
  relationship 
  as 
  

   dorsata 
  does 
  to 
  the 
  rest 
  of 
  the 
  wilkeUa 
  group. 
  Apart 
  from 
  

   these, 
  each 
  other 
  species 
  appears 
  to 
  me 
  to 
  be 
  isolated, 
  and 
  

   Mo 
  rice 
  has 
  shown 
  how 
  A. 
  liumilis 
  represents 
  a 
  considerable 
  

   number 
  of 
  species 
  on 
  the 
  Continent. 
  In 
  addition 
  to 
  the 
  

   fact 
  that 
  the 
  clypeus 
  is 
  white 
  or 
  yellow 
  in 
  all 
  but 
  one 
  

  

  