﻿STRUCTURE 
  OF 
  THE 
  CROP. 
  211 
  

  

  Dr. 
  Wilde, 
  of 
  Leipzig, 
  in 
  which, 
  p. 
  130, 
  he 
  gives 
  the 
  most 
  accurate 
  account 
  

   of 
  the 
  crop 
  and 
  proventriculus 
  of 
  the 
  Acridians 
  and 
  other 
  Orthoptera 
  

   which 
  has 
  yet 
  been 
  published. 
  

  

  The 
  crop 
  of 
  Andbrus 
  is 
  not 
  divided 
  iuto 
  two 
  parts, 
  and 
  its 
  cuticula 
  

   forms 
  no 
  ridges, 
  but 
  is 
  divided 
  up 
  into 
  distinct 
  fields 
  (Fig. 
  CO), 
  each 
  of 
  

   which 
  corresponds 
  to 
  a 
  siugle 
  epithelial 
  cell, 
  for 
  in 
  preparations 
  colored 
  

   with 
  logwood, 
  and 
  examined 
  from 
  the 
  surface, 
  a 
  sharply 
  defined, 
  round 
  

   nucleus 
  appears 
  in 
  the 
  middle 
  of 
  each 
  field. 
  Each 
  field 
  has 
  a 
  spine, 
  whicb 
  

   rises 
  from 
  its 
  posterior 
  part 
  and 
  points 
  backward. 
  These 
  spines 
  are 
  

   more 
  developed 
  than 
  their 
  fellows 
  on 
  the 
  cuticula 
  of 
  the 
  epidermis. 
  The 
  

   close 
  resemblance 
  of 
  the 
  two 
  cuticulse 
  serves 
  to 
  corroborate 
  the 
  view 
  

   that 
  the 
  crop 
  of 
  insects 
  arises 
  in 
  the 
  embryo, 
  as 
  a 
  secondary 
  invagination 
  

   of 
  the 
  ectoderm. 
  

  

  Proventriculus. 
  — 
  Dr. 
  Wilde, 
  in 
  the 
  article 
  just 
  mentioned, 
  speaks 
  of 
  

   the 
  "Kaumagen" 
  as 
  the 
  terminal 
  portion 
  of 
  the 
  crop, 
  but 
  I 
  see 
  no 
  ob- 
  

   jection 
  to 
  considering 
  it 
  entirely 
  distiuct 
  and 
  fully 
  equivalent 
  to 
  the 
  pro- 
  

   ventriculus 
  of 
  other 
  insects 
  with 
  which 
  it 
  is 
  homologous, 
  as 
  Wilde 
  has 
  

   already 
  pointed 
  out. 
  Wilde 
  appears 
  to 
  have 
  overlooked 
  the 
  fact 
  that 
  

   it 
  is 
  sharply 
  limited 
  both 
  in 
  front 
  and 
  behind, 
  and 
  in 
  his 
  figure 
  (1. 
  c, 
  

   Plate 
  IX, 
  Fig. 
  2) 
  the 
  front 
  limit 
  is 
  not 
  marked. 
  

  

  An 
  examination 
  of 
  the 
  proventriculus 
  opened, 
  and 
  spread 
  out 
  so 
  as 
  

   to 
  expose 
  the 
  inner 
  surface, 
  shows 
  that 
  there 
  are 
  six 
  large 
  teeth, 
  which 
  

   present 
  a 
  triangular 
  outline, 
  the 
  base 
  facing 
  frontwards, 
  the 
  apex 
  point- 
  

   ing 
  backwards. 
  The 
  ridges 
  of 
  the 
  crop 
  become 
  zigzag 
  just 
  in 
  front 
  of 
  

   the 
  bases 
  of 
  these 
  teeth 
  close 
  to 
  which 
  they 
  terminate. 
  Between 
  the 
  

   single 
  teeth 
  of 
  the 
  proventriculus 
  there 
  are 
  a 
  few 
  parallel 
  ridges, 
  which 
  

   are 
  not 
  continuous 
  with 
  those 
  of 
  the 
  crop, 
  and 
  which 
  terminate 
  abruptly 
  

   with 
  rounded 
  ends, 
  at 
  the 
  level 
  of 
  the 
  apices 
  of 
  the 
  large 
  teeth, 
  that 
  is 
  

   to 
  say 
  at 
  the 
  entrance 
  to 
  the 
  stomach. 
  In 
  the 
  apical 
  portions 
  of 
  the 
  

   large 
  teeth 
  there 
  is 
  more 
  or 
  less 
  pigment, 
  while 
  in 
  the 
  basal 
  portions 
  

   there 
  is 
  almost 
  none. 
  The 
  base 
  of 
  the 
  large 
  teeth 
  is 
  notched 
  j 
  the 
  apex 
  

   rounded 
  off 
  ; 
  and 
  their 
  surface 
  covered 
  with 
  a 
  multitude 
  of 
  minute 
  con- 
  

   ical 
  spines, 
  which 
  project 
  up 
  from 
  the 
  cuticula. 
  

  

  In 
  Anabrus 
  the 
  proventriculus 
  is 
  fully 
  developed, 
  and 
  resembles 
  that 
  

   of 
  other 
  crickets. 
  290 
  It 
  consists, 
  as 
  in 
  Gryllus 
  domesticus, 
  of 
  two 
  parts 
  : 
  

   one, 
  anterior, 
  serves 
  as 
  the 
  communication 
  between 
  the 
  crop 
  and 
  the 
  

   proventriculus 
  proper. 
  This 
  anterior 
  part 
  has 
  no 
  definite 
  limit 
  either 
  

   in 
  front 
  or 
  behind. 
  Both 
  parts 
  are 
  traversed 
  by 
  six 
  rows 
  of 
  teeth, 
  but, 
  

   though 
  the 
  rows 
  are 
  continuous, 
  the 
  form 
  of 
  the 
  teeth 
  differs 
  in 
  the 
  two 
  

   parts. 
  If 
  a 
  single 
  row 
  be 
  examined 
  it 
  will 
  be 
  seen 
  that 
  the 
  change 
  from 
  

   one 
  form 
  of 
  tooth 
  to 
  the 
  other 
  is 
  gradual, 
  not 
  abrupt. 
  A 
  transverse 
  

   section 
  through 
  the 
  posterior 
  part 
  of 
  the 
  proventriculus 
  shows 
  the 
  dis- 
  

   position 
  of 
  the 
  parts 
  to 
  be 
  as 
  drawn 
  in 
  Fig. 
  58. 
  Externally 
  is 
  the 
  muscu- 
  

   lar 
  coat, 
  consisting 
  mainly 
  of 
  circular 
  fibres, 
  intermingled 
  with 
  tracheae. 
  

   I 
  have 
  not 
  succeeded 
  in 
  detecting 
  any 
  longitudinal 
  fibres 
  in 
  transverse 
  

  

  **Wilde, 
  1. 
  c. 
  Arch. 
  f. 
  Naturgesch., 
  1877, 
  1. 
  Bd.,pp. 
  159-165. 
  

  

  