﻿358 
  ANNUAL, 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1922. 
  

  

  The 
  walls 
  of 
  the 
  Malpighian 
  tubules 
  are 
  regenerated, 
  but 
  the 
  

   tubes 
  do 
  not 
  change 
  much 
  in 
  form. 
  The 
  silk 
  glands 
  are 
  greatly 
  

   reduced 
  in 
  size 
  and 
  the 
  silk 
  press 
  and 
  the 
  spinneret 
  are 
  not 
  re- 
  

   formed 
  at 
  all. 
  The 
  ducts 
  of 
  the 
  new 
  glands, 
  which 
  are 
  to 
  have 
  a 
  

   new 
  function, 
  open 
  into 
  the 
  mouth. 
  

  

  None 
  of 
  these 
  organs 
  ever 
  loses 
  its 
  continuity. 
  Each 
  is 
  always 
  

   present 
  in 
  some 
  form 
  during 
  all 
  of 
  the 
  pupal 
  period. 
  But 
  the 
  reor- 
  

   ganization 
  that 
  affects 
  the 
  muscles 
  is 
  so 
  thorough 
  that 
  many 
  lose 
  

   their 
  integrity 
  for 
  a 
  while. 
  Some 
  that 
  were 
  intended 
  only 
  for 
  the 
  

   use 
  of 
  the 
  caterpillar 
  are 
  destroyed 
  completely, 
  others 
  are 
  remod- 
  

   eled, 
  and 
  new 
  ones 
  are 
  built 
  up 
  expressly 
  for 
  the 
  use 
  of 
  the 
  adult. 
  

  

  Other 
  internal 
  parts, 
  such 
  as 
  the 
  nervous 
  system, 
  the 
  heart, 
  the 
  

   respiratory 
  tubes, 
  and 
  the 
  reproductive 
  organs, 
  do 
  not 
  suffer 
  any 
  

   disintegration 
  but 
  grow 
  to 
  the 
  mature 
  form 
  in 
  the 
  ordinary 
  manner 
  

   of 
  development. 
  

  

  The 
  cells 
  of 
  the 
  fat 
  body 
  separate 
  from 
  one 
  another 
  in 
  the 
  pupa 
  

   and 
  float 
  about 
  in 
  the 
  body 
  cavity 
  as 
  a 
  mass 
  of 
  free 
  globular 
  cells. 
  

   They 
  give 
  up 
  their 
  oil 
  droplets 
  either 
  by 
  absorption 
  or 
  by 
  the 
  dis- 
  

   solving 
  of 
  their 
  thin 
  walls, 
  which 
  scatters 
  their 
  contents 
  broadcast 
  

   in 
  the 
  blood. 
  In 
  some 
  insects, 
  however, 
  the 
  fat 
  cells 
  assume 
  a 
  new 
  

   function 
  during 
  the 
  pupal 
  period 
  ; 
  they 
  absorb 
  and 
  appear 
  to 
  digest 
  

   material 
  derived 
  from 
  the 
  debris 
  of 
  the 
  old 
  organs, 
  especially 
  the 
  

   dissolving 
  muscles, 
  and 
  convert 
  this 
  material 
  into 
  albuminoid 
  prod- 
  

   ucts 
  that 
  accumulate 
  in 
  their 
  protoplasm 
  in 
  the 
  form 
  of 
  small 
  

   granules. 
  These 
  albuminous 
  bodies 
  are 
  finally 
  reabsorbed 
  into 
  the 
  

   blood 
  or 
  are 
  liberted 
  by 
  the 
  breaking 
  of 
  the 
  walls 
  of 
  the 
  fat 
  cells 
  

   and 
  are 
  used 
  as 
  food 
  by 
  the 
  developing 
  tissues 
  of 
  the 
  adult. 
  

  

  From 
  all 
  this 
  we 
  see 
  that 
  the 
  pupa 
  is 
  far 
  from 
  being 
  dead 
  ; 
  from 
  a 
  

   physiological 
  standpoint 
  it 
  is 
  very 
  much 
  alive 
  and 
  active. 
  But 
  its 
  

   activities 
  are 
  not 
  a 
  part 
  of 
  the 
  drama 
  of 
  the 
  insect's 
  life 
  — 
  the 
  pupal 
  

   stage 
  is 
  a 
  period 
  of 
  intermission 
  between 
  the 
  two 
  main 
  acts 
  when 
  a 
  

   great 
  commotion 
  of 
  scene 
  shifting 
  and 
  costume 
  changing 
  goes 
  on 
  

   behind 
  the 
  curtain 
  of 
  the 
  pupal 
  shell. 
  

  

  THE 
  MOTH. 
  

  

  For 
  three 
  weeks 
  or 
  a 
  little 
  longer 
  the 
  processes 
  of 
  reconstruction 
  

   go 
  on 
  within 
  the 
  pupa, 
  and 
  then 
  the 
  creature 
  that 
  was 
  a 
  caterpillar 
  

   breaks 
  through 
  its 
  coverings 
  and 
  appears 
  in 
  the 
  form 
  and 
  costume 
  

   of 
  a 
  moth. 
  The 
  pupal 
  shell 
  splits 
  open 
  at 
  the 
  front 
  end 
  (fig. 
  17, 
  E) 
  to 
  

   allow 
  the 
  moth 
  to 
  emerge, 
  but 
  the 
  latter 
  then 
  only 
  finds 
  itself 
  face 
  to 
  

   face 
  with 
  the 
  wall 
  of 
  the 
  cocoon. 
  It 
  has 
  left 
  behind 
  its 
  cutting 
  in- 
  

   struments, 
  the 
  mandibles, 
  with 
  its 
  discarded 
  overalls; 
  but 
  it 
  has 
  

   turned 
  chemist 
  and 
  needs 
  no 
  tools. 
  The 
  glands 
  that 
  furnished 
  the 
  

   silk 
  for 
  building 
  the 
  cocoon 
  now, 
  in 
  their 
  altered 
  state, 
  secrete 
  a 
  clear 
  

  

  