﻿350 
  

  

  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1922. 
  

  

  and 
  varies 
  in 
  size 
  according 
  to 
  the 
  amount 
  of 
  food 
  it 
  contains 
  (A 
  

   and 
  B, 
  Or). 
  The 
  stomach 
  (Vent) 
  is 
  the 
  largest 
  part 
  of 
  the 
  canal. 
  

   Its 
  walls 
  are 
  loose 
  and 
  wrinkled 
  when 
  it 
  is 
  empty, 
  or 
  smooth 
  and 
  tense 
  

   when 
  it 
  is 
  full. 
  The 
  intestine 
  (Int) 
  consists 
  of 
  three 
  divisions, 
  a 
  

   short 
  part 
  just 
  back 
  of 
  the 
  stomach, 
  a 
  larger 
  middle 
  part, 
  and 
  a 
  

   saclike 
  end 
  part 
  called 
  the 
  rectum 
  (Rect). 
  Six 
  long 
  tubes 
  (Mai) 
  

   are 
  wrapped 
  in 
  many 
  coils 
  about 
  the 
  intestine 
  and 
  run 
  forward 
  and 
  

   back 
  in 
  long 
  loops 
  over 
  the 
  rear 
  half 
  of 
  the 
  stomach. 
  The 
  three 
  on 
  

   each 
  side 
  unite 
  into 
  a 
  short 
  basal 
  tube, 
  which 
  opens 
  into 
  the 
  first 
  

   part 
  of 
  the 
  intestine. 
  The 
  terminal 
  parts 
  of 
  

   the 
  tubes 
  are 
  coiled 
  inside 
  the 
  muscular 
  coat 
  

   of 
  the 
  rectum. 
  These 
  tubes 
  are 
  known 
  as 
  the 
  

   Malpighian 
  tubules. 
  

  

  When 
  a 
  tent 
  caterpillar 
  goes 
  out 
  to 
  feed 
  

   the 
  fore 
  part 
  of 
  its 
  body 
  is 
  soft 
  and 
  flabby; 
  

   when 
  it 
  returns 
  to 
  the 
  tent 
  the 
  same 
  part 
  is 
  

   tight 
  and 
  firm. 
  This 
  is 
  because 
  the 
  cater- 
  

   pillar 
  carries 
  its 
  dinner 
  home 
  in 
  its 
  crop, 
  

   digests 
  it 
  slowly 
  while 
  in 
  the 
  tent, 
  and 
  then 
  

   goes 
  out 
  for 
  more 
  when 
  the 
  crop 
  is 
  empty. 
  It 
  

   is 
  quite 
  easy 
  to 
  tell 
  by 
  feeling 
  a 
  caterpillar 
  

   whether 
  it 
  is 
  hungry 
  or 
  not. 
  The 
  empty, 
  con- 
  

   tracted 
  crop 
  is 
  a 
  small 
  bag 
  contained 
  in 
  the 
  

   first 
  three 
  segments 
  of 
  the 
  body 
  (fig. 
  14, 
  A, 
  

   Or) 
  ; 
  but 
  the 
  full 
  crop 
  stretches 
  out 
  to 
  a 
  long 
  

   cylinder 
  like 
  a 
  sausage, 
  filling 
  the 
  first 
  six 
  

   segments 
  of 
  the 
  body 
  (fig. 
  14, 
  B), 
  its 
  rear 
  end 
  

   sunken 
  into 
  the 
  stomach 
  and 
  its 
  front 
  end 
  

   pressed 
  against 
  the 
  back 
  of 
  the 
  head. 
  

  

  The 
  fresh 
  food 
  in 
  the 
  crop 
  consists 
  of 
  a 
  

   soft, 
  pulpy 
  mass 
  of 
  leaf 
  fragments. 
  As 
  this 
  

   is 
  passed 
  into 
  the 
  stomach 
  the 
  crop 
  contracts 
  

   and 
  the 
  stomach 
  expands, 
  and 
  the 
  caterpillar's 
  

   center 
  of 
  gravity 
  is 
  shifted 
  backward 
  with 
  

   the 
  food 
  burden. 
  The 
  food 
  is 
  digested 
  in 
  the 
  stomach 
  and 
  the 
  un- 
  

   digested 
  part 
  is 
  passed 
  on 
  into 
  the 
  intestine. 
  As 
  the 
  stomach 
  be- 
  

   comes 
  empty 
  there 
  accumulates 
  in 
  it 
  a 
  dark-brown 
  liquid, 
  probably 
  

   the 
  gastric 
  juice, 
  and 
  it 
  becomes 
  inflated 
  with 
  bubbles 
  of 
  gas. 
  

   When 
  the 
  caterpillar 
  goes 
  to 
  its 
  meals 
  both 
  crop 
  and 
  stomach 
  are 
  

   sometimes 
  empty, 
  but 
  usually 
  the 
  stomach 
  still 
  contains 
  some 
  food 
  

   besides 
  an 
  abundance 
  of 
  the 
  brown 
  liquid 
  and 
  numerous 
  gas 
  bub- 
  

   bles. 
  The 
  refuse 
  that 
  accumulates 
  in 
  the 
  middle 
  section 
  of 
  the 
  

   intestine 
  is 
  subjected 
  to 
  pressure 
  by 
  the 
  muscles 
  of 
  the 
  intestinal 
  

   wall, 
  and 
  is 
  here 
  molded 
  into 
  a 
  pellet 
  which 
  retains 
  the 
  imprint 
  

   of 
  the 
  constrictions 
  and 
  pouches 
  of 
  this 
  part 
  of 
  the 
  intestine, 
  

  

  Fig. 
  14. 
  — 
  The 
  alimentary 
  

   canal 
  of 
  the 
  caterpillar. 
  

   A, 
  before 
  feeding 
  ; 
  B, 
  

   after 
  feeding. 
  Cr, 
  crop 
  ; 
  

   Int, 
  intestine 
  ; 
  Mai, 
  Mal- 
  

   pighian 
  tubules; 
  OE, 
  

   oesophagus 
  ; 
  Vent, 
  stom- 
  

   ach 
  or 
  ventriculus. 
  

  

  