﻿THE 
  BRAIN 
  OF 
  THE 
  LOCUST. 
  233 
  

  

  pears 
  that 
  there 
  are 
  four 
  bundles 
  of 
  nerve-fibers 
  passing 
  out 
  of 
  each 
  

   body. 
  A 
  bundle 
  of 
  transverse 
  nerve-fibers 
  (Fig. 
  2 
  t. 
  c. 
  n. 
  and 
  Fig. 
  3) 
  

   passes 
  along 
  under 
  the 
  central 
  body, 
  directly 
  through 
  the 
  middle 
  of 
  the 
  

   trabecular 
  and 
  anastomoses 
  with 
  the 
  fibrous 
  envelope 
  of 
  each 
  trabecula. 
  

   In 
  front 
  of 
  this 
  transverse 
  intra- 
  trabecular 
  nerve 
  is 
  a 
  small 
  short 
  ascend- 
  

   ing 
  bundle 
  of 
  fibers 
  (Fig. 
  3, 
  a. 
  t. 
  n.) 
  which 
  passes 
  next 
  to 
  the 
  pedicel, 
  but 
  

   does 
  not 
  apparently 
  form 
  a 
  part 
  of 
  it, 
  but 
  anastomoses 
  with 
  the 
  fibers 
  

   on 
  each 
  side 
  of 
  the 
  central 
  body. 
  Below, 
  the 
  fibres 
  pass 
  downward 
  and 
  

   outward 
  to 
  apparently 
  connect 
  with 
  the 
  fibrous 
  envelope 
  of 
  the 
  trabec- 
  

   ula. 
  Another 
  short 
  bundle 
  passes 
  out 
  from 
  the 
  trabecula 
  obliquely 
  to- 
  

   wards 
  the 
  central 
  body 
  and 
  anastomoses 
  with 
  the 
  fibrous 
  envelope 
  of 
  

   the 
  central 
  body. 
  

  

  Below, 
  but 
  in 
  the 
  same 
  plane, 
  is 
  another 
  transverse 
  bundle 
  of 
  fibers 
  

   (Fig. 
  3, 
  I. 
  t. 
  w.), 
  which 
  is 
  slightly 
  curved 
  and 
  on 
  the 
  left 
  side 
  its 
  fibers 
  

   are 
  distinctly 
  seen 
  to 
  enter 
  the 
  trabecula. 
  This 
  lower 
  intratrabecular 
  

   nerve, 
  as 
  we 
  may 
  call 
  it, 
  connects 
  with 
  three 
  vertical 
  short 
  nerves 
  aris- 
  

   ing 
  from 
  near 
  the 
  edge 
  of 
  the 
  lower 
  furrow 
  between 
  the 
  hemispheres 
  of 
  

   the 
  brain. 
  Of 
  these, 
  the 
  central 
  one 
  (centr. 
  n.) 
  is 
  in 
  the 
  median 
  line 
  of 
  

   the 
  brain, 
  and 
  the 
  lateral 
  ones 
  (lat. 
  n.) 
  are 
  on 
  each 
  side. 
  There 
  would 
  

   thus 
  seem 
  to 
  be 
  a 
  direct 
  double 
  nervous 
  communication 
  between 
  the 
  two 
  

   trabeculae, 
  and 
  with 
  the 
  fibers 
  surrounding 
  the 
  central 
  body, 
  and 
  hence 
  

   with 
  the 
  rest 
  of 
  the 
  brain. 
  This 
  seems 
  to 
  be 
  opposed 
  to 
  the 
  statement 
  of 
  

   Newton 
  that 
  the 
  trabeculae, 
  and 
  the 
  mushroom 
  bodies 
  in 
  general, 
  have 
  no 
  

   nervous 
  connection 
  with 
  the 
  rest 
  of 
  the 
  brain. 
  This 
  section 
  also 
  clearly 
  

   indicates 
  the 
  origin 
  of 
  the 
  optic 
  nerve, 
  which 
  passes 
  behind 
  the 
  stalk 
  of 
  

   the 
  mushroom 
  body, 
  and 
  also 
  the 
  relation 
  of 
  the 
  fibers 
  of 
  the 
  stalk 
  to 
  

   the 
  calices, 
  as 
  they 
  appear 
  to 
  penetrate 
  far 
  into 
  the 
  interior 
  of 
  the 
  body 
  

   of 
  each 
  calyx. 
  

  

  The 
  double 
  stalk 
  (cauliculus 
  and 
  peduncle). 
  — 
  These 
  names 
  are 
  applied 
  

   to 
  the 
  larger 
  and 
  smaller 
  divisions 
  of 
  the 
  stalk 
  of 
  the 
  "mushroom 
  body." 
  

   They 
  are 
  represented 
  in 
  the 
  eighteenth 
  section 
  (Fig. 
  4) 
  where 
  the 
  outer 
  

   part 
  of 
  the 
  stalk 
  (cauliculus) 
  supports 
  the 
  outer 
  calyx, 
  and 
  the 
  inner 
  

   slenderer 
  column 
  of 
  fibers 
  supports 
  or 
  ends 
  in 
  the 
  inner 
  division 
  of 
  the 
  

   calyx. 
  These 
  two 
  bundles 
  of 
  fibers 
  are 
  somewhat 
  curved, 
  but 
  as 
  they 
  

   do 
  not 
  appear 
  in 
  sections' 
  16 
  and 
  19, 
  must 
  be 
  less 
  than 
  ^J^ 
  of 
  an 
  inch 
  

   thick. 
  Their 
  fibers 
  are 
  seen 
  to 
  penetrate 
  deeply 
  into 
  the 
  base 
  of 
  the 
  

   calices, 
  and 
  thus 
  to 
  directly 
  communicate 
  with 
  the 
  fine 
  granular 
  sub- 
  

   stance 
  of 
  the 
  calices. 
  

  

  The 
  calices.— 
  The 
  cups 
  of 
  the 
  mushroom 
  bodies 
  in 
  the 
  locust 
  differ 
  

   decidedly 
  in 
  form 
  from 
  those 
  of 
  the 
  cockroach, 
  and 
  this 
  part 
  of 
  the 
  

   mushroom 
  body 
  is 
  more 
  variable 
  in 
  form 
  in 
  the 
  different 
  orders 
  of 
  insects 
  

   than 
  any 
  of 
  the 
  other 
  parts 
  of 
  the 
  brain. 
  It 
  is 
  nearly 
  obsolete, 
  or, 
  as 
  

   Flogel 
  states, 
  "not 
  more 
  than 
  rudimentary" 
  in 
  hemipterous 
  insects 
  

   (notably 
  Syrc-mastes), 
  and 
  is 
  less 
  completely 
  developed 
  in 
  many 
  smaller 
  

   moths, 
  beetles, 
  and 
  flies, 
  as 
  well 
  as 
  Neuroptera 
  (JEschna), 
  according 
  to 
  

   Flogel, 
  than 
  in 
  the 
  larger 
  moths, 
  in 
  the 
  Orthoptera, 
  and 
  especially 
  in 
  the 
  

  

  