﻿196 
  REPORT 
  UNITED 
  STATES 
  ENTOMOLOGICAL 
  COMMISSION. 
  

  

  This 
  is 
  not 
  the 
  place 
  to 
  describe 
  the 
  single 
  muscles 
  of 
  the 
  body, 
  but 
  

   there 
  is 
  one 
  which 
  I 
  will 
  mention, 
  because 
  its 
  disposition 
  can 
  hardly 
  be 
  

   seen 
  as 
  clearly 
  in 
  any 
  other 
  way 
  but 
  in 
  a 
  section 
  through 
  the 
  abdomen. 
  

   The 
  muscle 
  in 
  question 
  is 
  shown 
  in 
  Fig. 
  6 
  r. 
  m., 
  and 
  may 
  be 
  called 
  the 
  

   M. 
  respiratorius, 
  for 
  it 
  serves 
  to 
  approximate 
  the 
  upper 
  and 
  lower 
  cuti- 
  

   cular 
  arches 
  (Fig. 
  2 
  D 
  and 
  V) 
  and 
  so 
  to 
  diminish 
  the 
  capacity 
  of 
  the 
  

   abdomen, 
  hence 
  it 
  is 
  to 
  be 
  concluded 
  that 
  it 
  subserves 
  the 
  act 
  of 
  expira- 
  

   tion. 
  It 
  has 
  a 
  broad 
  attachment 
  to 
  the 
  lower 
  part 
  of 
  the 
  side 
  of 
  the 
  

   dorsal 
  arch 
  (cf. 
  Fig. 
  2 
  r. 
  m.) 
  and 
  a 
  narrow 
  insertion 
  into 
  the 
  upper 
  edge 
  

   or 
  rim 
  of 
  the 
  ventral 
  arch. 
  It 
  is 
  surrounded 
  by 
  a 
  network 
  of 
  fibrous 
  

   connective 
  tissue. 
  Graber 
  256 
  calls 
  this 
  muscle 
  the 
  "dorso- 
  ventral." 
  In 
  

   the 
  living 
  grasshopper 
  the 
  respiratory 
  movements 
  of 
  the 
  two 
  arches 
  are 
  

   readily 
  seen. 
  

  

  ORGANS 
  OF 
  CIRCULATION. 
  

  

  These 
  organs 
  I 
  have 
  not 
  examined 
  with 
  sufficient 
  attention 
  to 
  justify 
  

   the 
  publication 
  of 
  my 
  fragmentary 
  observations. 
  The 
  two 
  most 
  recent 
  

   articles 
  on 
  the 
  heart 
  are 
  by 
  Graber 
  257 
  and 
  Dogiel, 
  258 
  both 
  of 
  whom 
  refer 
  to 
  

   the 
  older 
  literature. 
  I 
  wish 
  also 
  to 
  use 
  this 
  occasion 
  to 
  refer 
  to 
  the 
  in- 
  

   vestigations 
  of 
  Graber 
  259 
  on 
  the 
  pulsating 
  ventral 
  sinus 
  of 
  insects, 
  and 
  

   the 
  discovery 
  of 
  ganglion 
  cells 
  in 
  the 
  heart 
  of 
  Crustacea 
  by 
  Dogiel 
  260 
  and 
  

   Berger. 
  261 
  The 
  student 
  should 
  also 
  compare 
  Burger's 
  paper 
  262 
  on 
  the 
  so- 
  

   called 
  ventral 
  vessel, 
  which 
  he 
  shows 
  to 
  be 
  really 
  a 
  cord 
  of 
  connective 
  

   tissue 
  surrounding 
  the 
  ventral 
  ganglionic 
  cord. 
  

  

  CONNECTIVE 
  TISSUE. 
  

  

  In 
  insects 
  all 
  the 
  internal 
  organs 
  of 
  the 
  body 
  are, 
  so 
  to 
  speak, 
  spun 
  

   around 
  by 
  a 
  web 
  of 
  fibrous 
  and 
  fatty 
  tissue, 
  which 
  extends 
  in 
  the 
  space 
  

   between 
  the 
  outer 
  body 
  wall 
  and 
  the 
  digestive 
  tract, 
  so 
  as 
  to 
  surround 
  

   all 
  the 
  intermediate 
  parts. 
  This 
  is 
  the 
  connective 
  tissue, 
  which 
  also 
  

   acts 
  as 
  carrier 
  or 
  staging 
  of 
  the 
  tracheae. 
  The 
  arrangement 
  of 
  this 
  net- 
  

   work 
  is 
  such 
  that 
  the 
  spaces 
  left 
  between 
  the 
  beams 
  or 
  threads 
  of 
  it 
  form 
  

   a 
  system 
  of 
  lacunar 
  spaces, 
  which 
  serve 
  as 
  channels 
  for 
  the 
  circulation 
  

   by 
  being 
  directly 
  connected 
  with 
  the 
  arteries 
  on 
  the 
  one 
  hand 
  and 
  the 
  

   veins 
  on 
  the 
  other. 
  Indeed 
  it 
  is 
  not 
  improbable 
  that 
  the 
  distinctive 
  

   blood-vessels 
  are 
  nothing 
  more 
  than 
  specialized 
  lacunae 
  of 
  the 
  con- 
  

   nective 
  tissue, 
  so 
  that 
  it 
  would 
  be 
  eminently 
  proper 
  to 
  consider 
  the 
  vas- 
  

  

  266 
  Graber: 
  Denkachr. 
  Wien. 
  Akad., 
  Bd. 
  36, 
  p. 
  75. 
  

  

  257 
  Graber: 
  Ueber 
  den 
  propulsatorischen 
  Apparat 
  dor 
  Insecten. 
  Arch., 
  f. 
  mikros. 
  Anat., 
  ix 
  (1873), 
  p. 
  

   129. 
  

  

  268 
  Dogiel: 
  Anatomio 
  mid 
  Physiologic 
  des 
  Herzens 
  dor 
  Larve 
  von 
  Coretkra 
  plumicornis. 
  Mem. 
  Acad. 
  

   St. 
  Peterab., 
  xxiv, 
  No. 
  x 
  (1877). 
  

  

  259 
  Graber 
  : 
  Ueber 
  den 
  pulsirendcn 
  Bauchsinus 
  dor 
  Inaecten. 
  Arcb. 
  f. 
  mikroa. 
  Anat., 
  xii 
  (1876), 
  p. 
  

   575. 
  

  

  ' 
  zw 
  Dogiel 
  : 
  De 
  la 
  Structure 
  ot 
  dea 
  Ponctions 
  du 
  Coeur 
  dea 
  Crustacea. 
  Arch. 
  Phys., 
  1877, 
  p. 
  401.- 
  

  

  26i 
  Berger: 
  Ueber 
  daa 
  Vorkommen 
  von 
  Ganglienzellen 
  hn 
  Horzen 
  des 
  Pluaakrebse, 
  Vienna, 
  1877, 
  pub- 
  

   lished 
  by 
  Gerolda 
  Sohn. 
  

  

  2(i2 
  Burger, 
  Dionys: 
  Ubor 
  daa 
  aogenannte 
  Bauchgefiiaa 
  dor 
  Lepidopteren, 
  nebst, 
  etc. 
  Niederl. 
  Arch. 
  f. 
  

   Zool., 
  iii 
  (1876), 
  p. 
  97. 
  

  

  