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  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1943 
  

  

  concealed, 
  and 
  an 
  enemy 
  following 
  these 
  beacons 
  might 
  well 
  be 
  con- 
  

   fused 
  by 
  their 
  sudden 
  extinction. 
  An 
  example 
  of 
  the 
  more 
  elaborate 
  

   type 
  is 
  the 
  leaf 
  butterfly 
  (Kallima 
  paralekta). 
  This 
  insect 
  has 
  a 
  

   bright 
  orange, 
  brown, 
  and 
  whitish 
  pattern 
  of 
  bold 
  markings 
  on 
  the 
  

   upper 
  surface 
  of 
  its 
  wings, 
  which 
  make 
  it 
  a 
  conspicuous 
  sight 
  when 
  

   the 
  creature 
  is 
  flying. 
  On 
  alighting 
  on 
  a 
  twig, 
  however, 
  the 
  wings 
  

   immediately 
  close 
  together 
  over 
  the 
  back, 
  leaving 
  only 
  their 
  undersides 
  

   visible. 
  Both 
  in 
  color 
  and 
  in 
  form 
  the 
  closed 
  wings 
  look 
  amazingly 
  

   ]ike 
  a 
  dried 
  leaf 
  and 
  the 
  insect 
  is 
  suddenly 
  completely 
  concealed, 
  to 
  

   the 
  bewilderment 
  of 
  its 
  possible 
  pursuer. 
  

  

  The 
  other 
  type 
  of 
  disappearing 
  color 
  is 
  that 
  found 
  in 
  animals 
  with 
  

   iridescent 
  scales, 
  feathers, 
  etc. 
  A 
  gleaming 
  ruby 
  light, 
  as 
  on 
  the 
  throat 
  

   of 
  the 
  male 
  ruby-throated 
  hummingbird 
  (Archilochus 
  colubris), 
  is 
  

   suddenly 
  extinguished 
  as 
  the 
  bird, 
  in 
  its 
  darting 
  about, 
  alters 
  its 
  

   orientation 
  to 
  the 
  sunlight. 
  This 
  is, 
  in 
  effect, 
  disappearing 
  coloration 
  

   in 
  motion, 
  as 
  opposed 
  to 
  concealment 
  of 
  color 
  when 
  at 
  rest, 
  and 
  it 
  may 
  

   be 
  argued 
  that 
  when 
  in 
  motion 
  the 
  creature 
  is 
  less 
  in 
  need 
  of 
  camouflage 
  

   than 
  when 
  still, 
  but 
  within 
  this 
  lesser 
  sphere 
  of 
  necessity, 
  it 
  may 
  have 
  

   a 
  protective 
  effect. 
  

  

  THE 
  EFFECTIVENESS 
  OF 
  CONCEALING 
  COLORATION 
  IN 
  NATURE 
  

  

  There 
  has 
  been 
  much 
  difference 
  of 
  opinion 
  among 
  naturalists 
  as 
  to 
  

   the 
  real 
  effectiveness 
  of 
  concealing 
  coloration 
  in 
  animals, 
  some 
  esti- 
  

   mating 
  its 
  success 
  as 
  almost 
  unbelievably 
  complete, 
  while 
  others 
  con- 
  

   tend 
  that 
  it 
  has 
  no 
  value 
  whatever 
  and 
  is 
  a 
  reflection 
  of 
  a 
  purely 
  

   human 
  approach 
  to 
  the 
  subject. 
  This 
  paper 
  is 
  hardly 
  the 
  place 
  to 
  

   evaluate 
  the 
  arguments 
  and 
  the 
  evidence 
  pro 
  and 
  con, 
  but 
  it 
  may 
  be 
  

   pointed 
  out 
  that 
  the 
  great 
  majority 
  of 
  opinion 
  does 
  grant 
  it 
  some 
  

   effectiveness, 
  and, 
  what 
  is 
  even 
  more 
  important, 
  animals 
  that 
  are 
  what 
  

   we 
  call 
  concealingly 
  colored 
  seem, 
  by 
  their 
  habits, 
  to 
  rely 
  on 
  their 
  

   coloration 
  to 
  save 
  them 
  from 
  attack. 
  It 
  may 
  be 
  further 
  mentioned 
  

   that 
  the 
  application 
  to 
  man's 
  war 
  efforts 
  of 
  the 
  principles 
  involved 
  

   in 
  concealing 
  coloration 
  in 
  nature 
  have 
  been 
  generally 
  conceded 
  to 
  be 
  

   of 
  sufficient 
  effectiveness 
  to 
  warrant 
  their 
  continued 
  and 
  even 
  in- 
  

   creased 
  use. 
  We 
  are 
  not 
  concerned 
  in 
  this 
  brief 
  review 
  so 
  much 
  with 
  

   the 
  various 
  details 
  of 
  the 
  functions 
  of 
  concealing 
  coloration 
  as 
  with 
  

   a 
  survey 
  of 
  the 
  methods 
  by 
  which 
  it 
  is 
  attained. 
  

  

  CONCEALING 
  BODY 
  FORM 
  

  

  Not 
  only 
  are 
  many 
  animals 
  rendered 
  less 
  conspicuous 
  by 
  reason 
  of 
  

   their 
  coloration, 
  but 
  also 
  in 
  many 
  (and 
  some 
  of 
  the 
  most 
  startling) 
  

   cases 
  by 
  their 
  form 
  as 
  well. 
  We 
  have 
  already 
  had 
  a 
  suggestion 
  of 
  

   this 
  in 
  the 
  body 
  and 
  tail 
  flanges 
  that 
  tend 
  to 
  eliminate 
  or 
  conceal 
  

   shadow, 
  but 
  may 
  now 
  briefly 
  consider 
  some 
  of 
  the 
  main 
  types 
  of 
  dis- 
  

  

  