﻿232 
  Mr. 
  R. 
  C. 
  L. 
  Perkins 
  on 
  

  

  The 
  females 
  of 
  Nomada 
  naturally 
  spend 
  most 
  of 
  their 
  

   time 
  either 
  searching 
  for 
  the 
  burrows 
  of 
  their 
  hosts 
  or 
  in 
  

   the 
  neighbourhood 
  of 
  these. 
  When 
  a 
  large 
  number 
  are 
  

   seen 
  hovering 
  over 
  the 
  mouths 
  of 
  the 
  burrows 
  of 
  some 
  

   compact 
  colony, 
  investigating 
  these 
  on 
  the 
  wing 
  before 
  

   entering, 
  they 
  present 
  a 
  most 
  striking 
  appearance 
  — 
  not 
  

   only 
  large 
  species 
  like 
  armata, 
  lineola, 
  or 
  Q-fosciata, 
  but 
  

   even 
  moderate-sized 
  ones 
  like 
  hillana, 
  ruficornis 
  or 
  germa- 
  

   nica 
  become 
  conspicuous 
  and 
  appear 
  to 
  exhibit 
  their 
  

   bright 
  colours 
  to 
  the 
  best 
  advantage. 
  We 
  may 
  presume 
  

   that 
  these 
  colours 
  have 
  some 
  protective 
  value 
  against 
  

   such 
  predaceous 
  animals 
  as 
  might 
  attack 
  them, 
  since 
  they 
  

   are 
  thus 
  by 
  the 
  nature 
  of 
  their 
  habits 
  very 
  much 
  exposed 
  

   to 
  any 
  such 
  enemies 
  as 
  may 
  be 
  at 
  hand. 
  Certainly 
  the 
  

   Andrenas 
  are 
  not 
  exposed 
  to 
  the 
  same 
  extent, 
  for 
  when 
  

   once 
  the 
  work 
  of 
  provisioning 
  their 
  cells 
  has 
  begun, 
  they 
  

   as 
  a 
  rule 
  quickly 
  enter 
  the 
  burrows 
  with 
  their 
  load 
  of 
  

   pollen, 
  whereas 
  the 
  parasite 
  is 
  often 
  very 
  conspicuous 
  while 
  

   hovering 
  over 
  a 
  bare 
  soil 
  for 
  a 
  long 
  time 
  together 
  and 
  

   investigating 
  the 
  burrows, 
  to 
  find 
  one 
  which 
  is 
  in 
  a 
  fit 
  

   condition 
  for 
  its 
  entry. 
  Such 
  a 
  view 
  of 
  the 
  coloration 
  

   of 
  Nomada 
  is 
  far 
  preferable 
  to 
  that 
  which 
  supposes 
  the 
  

   wasp-like 
  or 
  conspicuous 
  colours 
  to 
  be 
  for 
  the 
  purpose 
  

   of 
  intimidating 
  the 
  host 
  ! 
  For 
  a 
  time 
  after 
  their 
  emergence 
  

   the 
  parasites 
  appear 
  to 
  resort 
  to 
  the 
  burrows, 
  where 
  they 
  

   were 
  born, 
  for 
  shelter 
  at 
  night 
  and 
  in 
  unfavourable 
  weather, 
  

   but 
  when 
  the 
  hosts 
  become 
  fully 
  occupied 
  with 
  their 
  

   labours, 
  the 
  Nomadas 
  habitually 
  remain 
  out 
  at 
  nights. 
  

   Some 
  of 
  them 
  sleep 
  clinging 
  by 
  the 
  mandibles 
  alone 
  to 
  

   the 
  heads 
  of 
  flowering 
  grasses, 
  the 
  legs 
  all 
  drawn 
  close 
  to 
  

   the 
  body 
  and 
  the 
  antennae 
  porrect, 
  so 
  as 
  to 
  resemble 
  a 
  

   little 
  stalk. 
  The 
  bright 
  colours 
  of 
  the 
  body 
  being 
  much 
  

   toned 
  down 
  by 
  the 
  closed 
  and 
  superincumbent 
  wings, 
  

   the 
  bees 
  closely 
  resemble 
  the 
  seeds 
  or 
  flowers 
  of 
  grasses, 
  

   and 
  are 
  often 
  difficult 
  to 
  detect. 
  Some 
  may 
  be 
  found 
  

   clinging 
  to 
  dead 
  twigs 
  or 
  leaves, 
  with 
  which 
  their 
  colours 
  

   also 
  harmonise 
  very 
  well. 
  On 
  grasses 
  I 
  have 
  taken 
  large 
  

   numbers 
  of 
  N 
  . 
  hillana 
  and 
  germanica, 
  and 
  also 
  of 
  the 
  very 
  

   minute 
  N. 
  furva; 
  while 
  attached 
  to 
  dead 
  hedgerow 
  

   branches 
  I 
  once 
  found 
  a 
  number 
  of 
  $ 
  iV. 
  bifida, 
  and 
  on 
  

   heather 
  many 
  N 
  . 
  rufipes. 
  

  

  Probably 
  all 
  the 
  species 
  of 
  Nomada 
  possess 
  a 
  strong 
  

   odour, 
  more 
  or 
  less 
  disagreeable 
  to 
  me 
  in 
  the 
  case 
  

   of 
  N. 
  tnarshamella, 
  but 
  rather 
  pleasant 
  in 
  the 
  case 
  of 
  

  

  