﻿240 
  REPORT 
  UNITED 
  STATES 
  ENTOMOLOGICAL 
  COMMISSION. 
  

  

  First 
  pupal 
  stage 
  of 
  Caloptenus 
  spretus. 
  — 
  My 
  sections 
  are 
  too 
  imperfect 
  

   to 
  describe, 
  but 
  the 
  form 
  of 
  the 
  brain 
  is 
  closely 
  like 
  that 
  of 
  the 
  next 
  stage. 
  

  

  Second 
  or 
  last 
  pupal 
  stage 
  of 
  Caloptenus 
  spretus. 
  — 
  A 
  number 
  (14) 
  of 
  very 
  

   successful 
  sections 
  made 
  by 
  Mr. 
  Mason 
  from 
  one 
  head 
  give 
  an 
  excellent 
  

   opportunity 
  for 
  studying 
  the 
  head 
  of 
  the 
  locust 
  in 
  this 
  stage, 
  just 
  be- 
  

   fore 
  becoming 
  fledged 
  (see 
  first 
  Eeport^ 
  PI. 
  I, 
  Fig. 
  5). 
  Of 
  these 
  sections, 
  

   Nos. 
  8 
  and 
  9 
  pass 
  through 
  the 
  calices 
  and 
  oesophageal 
  lobes, 
  but 
  do 
  not 
  

   reach 
  the 
  central 
  body. 
  Section 
  10 
  (Fig. 
  1 
  of 
  PI. 
  XIV) 
  passes 
  through 
  

   the 
  central 
  body, 
  which 
  is 
  ¥ 
  ^q 
  of 
  an 
  inch 
  in 
  thickness, 
  the 
  section 
  itself 
  

   being 
  of 
  the 
  same 
  thickness. 
  In 
  the 
  optic 
  ganglion 
  the 
  section 
  passes 
  

   through 
  the 
  front 
  of 
  it, 
  but 
  two 
  lenticular 
  masses 
  appear. 
  The 
  trabe- 
  

   cule 
  are 
  as 
  in 
  the 
  adult, 
  and 
  the 
  superior 
  and 
  inferior 
  intra-trabecular 
  

   nerves 
  are 
  clearly 
  seen 
  to 
  pass 
  into 
  the 
  center 
  of 
  each 
  trabecula 
  just 
  as 
  

   in 
  the 
  adult. 
  On 
  the 
  left 
  side 
  the 
  origin 
  of 
  the 
  cauliculus 
  and 
  peduncle 
  

   is 
  clearly 
  seen, 
  under 
  a 
  power 
  of 
  225 
  and 
  of 
  400 
  diameters, 
  the 
  relation 
  

   of 
  parts 
  being 
  exactly 
  as 
  in 
  the 
  adult 
  (see 
  PI. 
  X, 
  Fig. 
  3). 
  The 
  base 
  of 
  

   the 
  two 
  divisions 
  of 
  the 
  double 
  stalk 
  arise 
  suddenly, 
  as 
  if 
  inserted 
  into 
  

   or 
  resting 
  simply 
  upon, 
  rather 
  than 
  arising 
  from, 
  the 
  trabecule 
  ; 
  the 
  

   bases 
  of 
  the 
  cauliculus 
  and 
  peduncle 
  being 
  in 
  the 
  same 
  line 
  with 
  the 
  

   base 
  of 
  the 
  center 
  of 
  the 
  upper 
  division 
  of 
  the 
  central 
  body. 
  It 
  ap- 
  

   pears 
  as 
  if 
  a 
  few 
  nerve 
  fibers 
  passed 
  under 
  the 
  base 
  of 
  the 
  stalk 
  between 
  

   it 
  and 
  the 
  trabecula 
  ; 
  at 
  any 
  rate, 
  I 
  have 
  been 
  unable 
  to 
  observe 
  either 
  

   in 
  the 
  pupa 
  or 
  larva 
  or 
  adult, 
  among 
  a 
  number 
  of 
  preparations, 
  any 
  con- 
  

   tinuity 
  between 
  the 
  trabecule 
  and 
  the 
  double 
  stalk. 
  

  

  In 
  this 
  section 
  the 
  curving 
  of 
  the 
  double 
  stalk 
  backwards 
  and 
  the 
  

   passage 
  in 
  front 
  of 
  this 
  double 
  column 
  is 
  to 
  be 
  clearly 
  seen, 
  and 
  is 
  just 
  

   as 
  we 
  have 
  described 
  it 
  from 
  similar 
  sections 
  of 
  the 
  adult 
  brain 
  (Fig. 
  

   3 
  of 
  PI. 
  X). 
  The 
  ball 
  like 
  masses 
  in 
  the 
  oesophageal 
  commissures 
  are 
  

   as 
  distinctly 
  shown 
  as 
  in 
  the 
  adult. 
  

  

  Section 
  11 
  passes 
  behind 
  the 
  central 
  body, 
  not 
  showing 
  it 
  nor 
  the 
  

   basal 
  part 
  of 
  the 
  double 
  stalk 
  of 
  the 
  mushroom 
  body. 
  This 
  section, 
  and 
  

   those 
  behind 
  it, 
  show 
  well 
  the 
  structure 
  of 
  the 
  optic 
  ganglion. 
  In 
  sec- 
  

   tion 
  11 
  the 
  three 
  lenticular 
  bodies 
  clearly 
  appear. 
  

  

  The 
  main, 
  and 
  almost 
  the 
  only, 
  difference 
  between 
  the 
  second 
  pupa 
  

   and 
  the 
  adult 
  appears 
  to 
  be 
  in 
  the 
  degree 
  of 
  development 
  of 
  the 
  central 
  

   body. 
  In 
  the 
  second 
  pupa 
  (PI. 
  XIV, 
  Fig. 
  3) 
  it 
  is 
  rather 
  more 
  elementary 
  

   than 
  in 
  the 
  adult, 
  the 
  upper 
  and 
  lower 
  series 
  of 
  unicellular 
  bodies 
  being 
  

   a 
  little 
  shorter 
  and 
  rounder, 
  nearer 
  their 
  primitive 
  condition, 
  and 
  the 
  

   septa 
  between 
  them 
  are 
  x>lainly 
  fibrous. 
  Their 
  contents 
  are 
  as 
  finely 
  

   granular 
  as 
  the 
  adjoining 
  parts 
  of 
  the 
  body. 
  

  

  Section 
  11 
  is 
  instructive 
  as 
  showing 
  a 
  bundle 
  of 
  directly 
  ascending 
  

   and 
  obliquely 
  ascending 
  fibers 
  from 
  the 
  back 
  part 
  of 
  the 
  trabecula, 
  of 
  

   which 
  a 
  portion 
  is 
  contained 
  in 
  the 
  section. 
  Two 
  large 
  bundles 
  enter 
  

   the 
  commissural 
  lobes, 
  one 
  from 
  above 
  and 
  one 
  from 
  the 
  inner 
  side 
  under 
  

   the 
  central 
  body, 
  the 
  bundle 
  from 
  above 
  passing 
  down 
  into 
  the 
  lobe 
  from 
  

   around 
  the 
  upper 
  side 
  of 
  the 
  trabecula. 
  From 
  this 
  fact 
  we 
  should 
  infer 
  

  

  