﻿274 
  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  194 
  3 
  

  

  the 
  ruby 
  -throated 
  hummingbird 
  {Archilochus 
  colubris), 
  the 
  wood- 
  

   pewee 
  {Myiochanes 
  virens) 
  and 
  the 
  blue-gray 
  gnatcatcher 
  (Polioptila 
  

   caerulea) 
  cover 
  the 
  outsides 
  of 
  their 
  nests 
  with 
  lichens, 
  with 
  the 
  result 
  

   that 
  they 
  are 
  very 
  well 
  concealed. 
  

  

  Also 
  associated 
  with 
  bark 
  resemblance 
  are 
  those 
  cases 
  of 
  twig 
  re- 
  

   semblance, 
  well 
  illustrated 
  by 
  the 
  familiar 
  walking-stick 
  insect. 
  All 
  

   parts 
  of 
  the 
  body 
  are 
  here 
  modified 
  into 
  slender 
  twiglike 
  pieces, 
  and 
  

   the 
  joints 
  between 
  them 
  have 
  much 
  of 
  the 
  appearance 
  of 
  plant 
  nodes. 
  

   Furthermore, 
  the 
  postures 
  struck 
  by 
  the 
  insects 
  are 
  in 
  keeping 
  with 
  

   the 
  illusion 
  of 
  small 
  twigs. 
  As 
  a 
  matter 
  of 
  fact, 
  the 
  harmony 
  be- 
  

   tween 
  usual 
  posture 
  (which 
  is 
  not 
  rigidly 
  fixed 
  in 
  most 
  cases) 
  and 
  

   the 
  illusory 
  form 
  or 
  color 
  resemblance 
  in 
  many 
  of 
  these 
  concealingly 
  

   colored 
  animals 
  is 
  one 
  of 
  the 
  strongest 
  lines 
  of 
  evidence 
  for 
  the 
  reality 
  

   of 
  the 
  camouflage. 
  Otherwise, 
  it 
  might 
  well 
  be 
  a 
  purely 
  man-made 
  

   interpretation, 
  but 
  when 
  creatures 
  seem 
  to 
  act 
  according 
  to 
  this 
  color 
  

   or 
  form, 
  or 
  to 
  be 
  colored 
  and 
  shaped 
  according 
  to 
  their 
  normal 
  activi- 
  

   ties, 
  it 
  is 
  difficult 
  not 
  to 
  grant 
  the 
  reality 
  of 
  this 
  correlation. 
  

  

  In 
  the 
  sea 
  we 
  find 
  crustaceans 
  and 
  fishes 
  that 
  have 
  many 
  irregular 
  

   filamentous 
  appendages, 
  which 
  bring 
  about 
  an 
  astonishing 
  resem- 
  

   blance 
  to 
  the 
  seaweed 
  in 
  which 
  these 
  particular 
  species 
  live. 
  The 
  

   fauna 
  of 
  the 
  Sargasso 
  Sea, 
  an 
  area 
  in 
  the 
  Atlantic 
  Ocean 
  filled 
  with 
  

   the 
  Sargassum 
  weed, 
  are 
  perhaps 
  the 
  best-known 
  examples 
  of 
  this 
  

   kind, 
  although 
  others 
  occur 
  in 
  all 
  the 
  oceans 
  wherever 
  seaweeds 
  are 
  

   common. 
  There 
  are 
  numbers 
  of 
  species 
  of 
  small 
  fishes, 
  of 
  crabs, 
  etc., 
  

   that 
  spend 
  their 
  lives 
  in 
  the 
  floating 
  masses 
  of 
  Sargassum 
  weed, 
  and 
  

   of 
  this 
  ecologically 
  closely 
  limited 
  fauna, 
  the 
  percentage 
  of 
  seaweed 
  

   form 
  resemblance 
  is 
  high 
  indeed. 
  Specimens 
  taken 
  out 
  of 
  their 
  nat- 
  

   ural 
  environment 
  seem 
  merely 
  bizarre 
  curios 
  of 
  the 
  naturalists' 
  cab- 
  

   inet, 
  but 
  in 
  their 
  native 
  haunts 
  they 
  merge 
  completely 
  into 
  their 
  

   surroundings. 
  

  

  CONCLUSION 
  

  

  Camouflage 
  in 
  nature, 
  is, 
  then, 
  widespread, 
  both 
  in 
  all 
  parts 
  of 
  the 
  

   world, 
  and 
  within 
  all 
  groups 
  of 
  animals. 
  It 
  may 
  be 
  brought 
  about 
  

   by 
  coloration 
  alone, 
  by 
  form 
  alone, 
  or 
  by 
  any 
  possible 
  degree 
  and 
  type 
  

   of 
  combination 
  of 
  color 
  or 
  morphological 
  characters. 
  It 
  may 
  be 
  rig- 
  

   idly 
  fixed 
  or 
  remarkably 
  plastic. 
  Its 
  degree 
  of 
  success 
  in 
  different 
  

   forms 
  is 
  highly 
  variable, 
  and, 
  as 
  might 
  be 
  expected, 
  the 
  opinions 
  of 
  

   investigators 
  as 
  to 
  its 
  merits 
  have 
  been 
  equally 
  diverse. 
  In 
  this 
  brief 
  

   review 
  we 
  have 
  merely 
  pointed 
  out 
  some 
  of 
  the 
  types 
  of 
  camouflage, 
  

   have 
  given 
  some 
  idea 
  of 
  its 
  complexity, 
  of 
  its 
  multiplicity 
  of 
  methods 
  

   and 
  approaches, 
  and 
  of 
  the 
  astonishing 
  heights 
  of 
  deceptive 
  efficiency 
  

   it 
  attains 
  in 
  many 
  cases. 
  Such 
  controversial 
  outgrowths 
  of 
  the 
  sub- 
  

   jects 
  as 
  mimicry 
  and 
  the 
  theoretical 
  difficulties 
  it 
  entails 
  have 
  been 
  

   deliberately 
  left 
  out 
  of 
  the 
  present 
  discussion. 
  

  

  