﻿208 
  REPORT 
  UNITED 
  STATES 
  ENTOMOLOGICAL 
  COMMISSION. 
  

  

  in 
  some 
  sections 
  that 
  I 
  could 
  see 
  cilia, 
  but 
  this 
  point 
  I 
  could 
  not 
  settle 
  

   to 
  my 
  satisfaction. 
  There 
  is 
  a 
  thin, 
  but 
  distinct, 
  layer 
  of 
  connective 
  

   tissue 
  around 
  the 
  epithelium. 
  The 
  character 
  of 
  the 
  epithelium 
  is 
  not 
  

   the 
  same 
  throughout 
  this 
  upper 
  division. 
  In 
  the 
  lower 
  part, 
  when 
  seen 
  

   from 
  the 
  inner 
  surface, 
  the 
  epithelium 
  presents 
  the 
  appearance 
  repre- 
  

   sented 
  in 
  Fig. 
  32, 
  the 
  nuclei 
  being 
  oval, 
  of 
  nearly 
  uniform 
  size, 
  and 
  quite 
  

   closely 
  crowded 
  together. 
  Higher 
  up 
  the 
  nuclei 
  are 
  further 
  apart 
  and 
  

   vary 
  considerably 
  in 
  their 
  dimensions 
  ; 
  the 
  outlines 
  of 
  the 
  cells 
  also 
  ap- 
  

   pear 
  more 
  clearly 
  as 
  pentagonal. 
  'Near 
  the 
  rounded 
  tip 
  the 
  distance 
  

   apart 
  of 
  the 
  nuclei 
  is 
  still 
  greater, 
  and 
  they 
  are 
  more 
  irregular 
  in 
  size. 
  

   In 
  some 
  of 
  the 
  specimens 
  I 
  have 
  examined 
  the 
  whole 
  upper 
  division 
  of 
  

   the 
  tube 
  was 
  crowded 
  with 
  bundles 
  of 
  spermatozoa. 
  In 
  one 
  tube 
  I 
  counted 
  

   over 
  200 
  bundles. 
  

  

  The 
  lower 
  end 
  of 
  the 
  upper 
  division 
  tapers 
  off, 
  the 
  nuclei 
  becoming 
  

   smaller 
  and 
  even 
  more 
  crowded 
  than 
  in 
  Fig. 
  32. 
  The 
  muscular 
  coat 
  ap- 
  

   pears 
  thin 
  at 
  first, 
  but, 
  increasing, 
  soon 
  acquires 
  its 
  full 
  thickness, 
  the 
  

   caliber 
  of 
  the 
  tube 
  diminishing 
  at 
  the 
  same 
  time. 
  A 
  transverse 
  section 
  

   of 
  this 
  lower 
  part 
  of 
  the 
  vesicula 
  (Fig. 
  34) 
  shows 
  that 
  the 
  epithelial 
  

   cells 
  are 
  very 
  much 
  smaller 
  than 
  in 
  the 
  upper 
  portion 
  (compare 
  Fig. 
  34 
  

   with 
  Fig 
  31, 
  both 
  being 
  equally 
  magnified 
  ^P) 
  $ 
  the 
  walls, 
  however, 
  

   rendered 
  very 
  much 
  thicker 
  by 
  the 
  enormous 
  muscular 
  coat, 
  Fig 
  34 
  Muc 
  r 
  

   the 
  fibres 
  of 
  which 
  appear 
  to 
  be 
  exclusively 
  circular. 
  

  

  I 
  have 
  also 
  made 
  a 
  complete 
  series 
  of 
  sections 
  through 
  the 
  posterior 
  

   end 
  of 
  the 
  abdomen 
  of 
  the 
  male, 
  some 
  of 
  which 
  display 
  very 
  beautifully 
  

   the 
  relations 
  of 
  the 
  parts, 
  but 
  these 
  structures 
  are 
  so 
  complicated 
  that 
  

   an 
  elaborate 
  investigation 
  is 
  necessary 
  to 
  secure 
  a 
  satisfactory 
  interpre- 
  

   tation 
  of 
  the 
  sections. 
  Therefore 
  I 
  must 
  reserve 
  the 
  subject 
  for 
  another 
  

   occasion. 
  

  

  DIGESTIVE 
  CANAL. 
  

  

  Of 
  the 
  digestive 
  canal 
  I 
  shall 
  give 
  a 
  more 
  complete 
  histological 
  

   description 
  than 
  I 
  have 
  of 
  the 
  other 
  systems. 
  Of 
  the 
  cavity 
  of 
  the 
  

   mouth 
  and 
  of 
  the 
  oesophagus 
  I 
  shall 
  say 
  but 
  little. 
  The 
  salivary 
  glands 
  

   I 
  have 
  not 
  studied 
  at 
  all, 
  for 
  want 
  of 
  proper 
  material. 
  Those 
  in 
  the 
  

   cockroach 
  have 
  been 
  described 
  by 
  von 
  Basch, 
  291 
  and 
  also 
  in 
  the 
  more 
  

   recent 
  superb 
  monograph 
  of 
  Kupffer. 
  292 
  Ley 
  dig 
  293 
  has 
  made 
  some 
  valua- 
  

   ble 
  observations. 
  The 
  glands 
  have 
  likewise 
  been 
  studied 
  in 
  other 
  insects 
  

   by 
  various 
  authors, 
  to 
  whom 
  I 
  need 
  not 
  refer 
  here. 
  

  

  In 
  order 
  to 
  render 
  my 
  description 
  easier 
  to 
  follow, 
  I 
  will 
  preface 
  my 
  

   account 
  by 
  a 
  brief 
  review 
  of 
  the 
  divisions 
  of 
  the 
  digestive 
  canal 
  in 
  

   locusts 
  5 
  my 
  own 
  investigations 
  having 
  shown 
  that 
  the 
  divisions 
  adopted 
  

   by 
  the 
  older 
  authors, 
  4 
  and 
  since 
  generally 
  introduced 
  in 
  all 
  text-books, 
  

  

  291 
  & 
  Bosch: 
  Untersuchungen 
  ueber 
  das 
  Chylopootiscke 
  unci 
  Uropoetische 
  System 
  der 
  Blatta 
  orien- 
  

   talis. 
  Sitzber. 
  Wien. 
  Akad., 
  xxxiii 
  (1858), 
  pp. 
  234. 
  Speicheldrtisen, 
  p. 
  235, 
  Taf. 
  v, 
  Fig. 
  11. 
  

  

  292 
  Kupffer 
  : 
  Die 
  Speicheldrtisen 
  von 
  Periplaneta 
  orientalis 
  und 
  ihr 
  Nervenapparat. 
  Beitriige 
  Anat. 
  

   Phys., 
  C. 
  Ludwig 
  gewidmet, 
  p. 
  C4, 
  Taf. 
  ix. 
  

  

  *« 
  Mtiller's 
  Arch., 
  1859, 
  pp. 
  59-70. 
  

  

  