﻿The 
  British 
  Species 
  of 
  Andrena 
  and 
  Nomado. 
  233 
  

  

  N. 
  goodeniana. 
  Kirby 
  noticed 
  it 
  specially 
  of 
  the 
  latter, 
  

   " 
  odore 
  me^mae.flagrantissima," 
  while 
  N. 
  lineola 
  {corni- 
  

   gera 
  K.) 
  " 
  moscham 
  redolet." 
  Some 
  at 
  times 
  feign 
  death 
  

   when 
  alarmed. 
  The 
  sting 
  even 
  of 
  the 
  larger 
  species 
  is 
  

   not 
  at 
  all 
  severe, 
  and 
  when 
  the 
  bee 
  is 
  taken 
  between 
  the 
  

   finger 
  and 
  thumb 
  the 
  cuticle 
  is 
  rarely 
  penetrated, 
  though 
  

   vigorous 
  attempts 
  are 
  made 
  to 
  do 
  so. 
  If 
  the 
  thin 
  skin 
  

   beneath 
  the 
  nail 
  is 
  pierced, 
  the 
  sting 
  is 
  sometimes 
  sufficiently 
  

   sharp, 
  as 
  I 
  have 
  myself 
  experienced, 
  to 
  cause 
  one 
  to 
  in- 
  

   voluntarily 
  relax 
  one's 
  hold 
  of 
  the 
  bee, 
  but 
  the 
  pain 
  is 
  

   short-lived. 
  It 
  is 
  impossible 
  to 
  help 
  noticing, 
  that 
  though 
  

   the 
  sting 
  is 
  feeble, 
  the 
  quite 
  remarkable 
  mobility 
  of 
  the 
  

   abdomen 
  admits 
  of 
  the 
  weapon 
  being 
  used 
  with 
  a 
  far 
  

   greater 
  range 
  of 
  movement 
  than 
  in 
  most 
  bees. 
  

  

  All 
  the 
  species 
  of 
  Nofnada 
  have 
  a 
  hard 
  and 
  thick 
  chitinous 
  

   cuticle, 
  forming 
  a 
  stronger 
  protection 
  from 
  injury 
  than 
  

   that 
  of 
  their 
  hosts. 
  Indeed, 
  it 
  may 
  be 
  accepted 
  as 
  an 
  

   almost 
  universal 
  law 
  that 
  in 
  parasitic 
  Aculeata 
  the 
  in- 
  

   tegument 
  is 
  less 
  easily 
  pierced 
  than 
  that 
  of 
  the 
  species 
  

   they 
  parasitise. 
  Thus 
  Coelioxys 
  is 
  harder 
  than 
  Megachile, 
  

   Crocisa 
  or 
  Melecta 
  than 
  Anthophora, 
  Epeohts 
  than 
  Colletes, 
  

   Psithyrus 
  than 
  Botnbus, 
  Chrysis 
  and 
  Sapyga 
  than 
  their 
  

   usual 
  hosts, 
  Nysson 
  than 
  Gorytes 
  and 
  Harpactus, 
  and 
  so 
  

   on. 
  Only 
  perhaps 
  in 
  the 
  case 
  of 
  a 
  few 
  species, 
  which 
  

   have 
  lately 
  taken 
  to 
  parasitism, 
  as 
  we 
  judge, 
  and 
  not 
  yet 
  

   become 
  greatly 
  modified 
  thereby, 
  does 
  this 
  fact 
  seem 
  

   hardly 
  apparent. 
  This 
  hardness 
  of 
  covering 
  (accompanied 
  

   as 
  it 
  often 
  is 
  by 
  spines, 
  prominences 
  or 
  projections) 
  may 
  

   be 
  of 
  use 
  to 
  the 
  parasites 
  as 
  a 
  protection 
  from 
  some 
  pre- 
  

   daceous 
  enemies, 
  or 
  even 
  conceivably 
  to 
  some 
  extent 
  from 
  

   the 
  unfavourable 
  w^eather, 
  to 
  which 
  their 
  mode 
  of 
  life 
  

   exposes 
  them, 
  but 
  one 
  cannot 
  help 
  suspecting 
  that 
  it 
  is 
  

   primarily 
  as 
  a 
  protection 
  against 
  attacks 
  of 
  their 
  hosts 
  

   that 
  their 
  thicker 
  armour 
  is 
  so 
  regularly 
  developed. 
  

  

  There 
  is 
  considerable 
  difference 
  of 
  opinion 
  as 
  to 
  the 
  

   frequency 
  of 
  conflict 
  between 
  host 
  and 
  parasite. 
  Shuckard 
  

   particularly 
  notices 
  the 
  fierce 
  fights 
  between 
  Anthophora 
  

   and 
  Melecta, 
  and 
  I 
  have 
  described 
  an 
  attack 
  on 
  Halictns 
  

   by 
  Sphecodes. 
  On 
  the 
  Continent 
  Marchal 
  saw 
  S. 
  sub- 
  

   quadratvs 
  kill 
  the 
  $ 
  of 
  H. 
  malachurus 
  and 
  take 
  possession 
  

   of 
  its 
  burrow. 
  Hedychrum 
  has 
  been 
  recorded 
  in 
  an 
  often- 
  

   quoted 
  passage 
  as 
  being 
  surprised 
  and 
  attacked 
  by 
  its 
  

   host, 
  and 
  as 
  protecting 
  itself 
  by 
  its 
  well-known 
  habit 
  of 
  

   rolling 
  itself 
  up 
  into 
  a 
  ball. 
  It 
  is 
  probable 
  that 
  fights 
  

  

  