﻿178 
  KEPORT 
  UNITED 
  STATES 
  ENTOMOLOGICAL 
  COMMISSION. 
  

  

  From 
  each 
  of 
  the 
  two 
  very 
  large 
  prothoracic 
  spiracles, 
  besides 
  two 
  

   small 
  tracheae, 
  a 
  very 
  large 
  barrel-shaped 
  dilated 
  trachea 
  is 
  directed 
  

   downwards 
  to 
  the 
  sternum. 
  It 
  communicates 
  directly 
  with 
  the 
  large 
  

   spiracle 
  as 
  the 
  point 
  of 
  a 
  needle 
  or 
  knife 
  when 
  passed 
  through 
  the 
  

   spiracle 
  entered 
  directly 
  into 
  this 
  trachea. 
  

  

  CHAPTER 
  IX. 
  

  

  THE 
  AIR-SACS 
  OF 
  LOCUSTS 
  WITH 
  REFERENCE 
  TO 
  THEIR 
  

   POWERS 
  OF 
  FLIGHT. 
  (Plate 
  I.) 
  

  

  In 
  the 
  ninth 
  chapter 
  of 
  our 
  First 
  Report 
  we 
  briefly 
  described 
  the 
  dis- 
  

   tribution 
  of 
  the 
  air 
  sacs 
  in 
  the 
  locust, 
  and 
  indicated 
  that 
  its 
  great 
  powers 
  

   of 
  flight 
  were 
  largely 
  due 
  to 
  the 
  fact 
  that 
  this 
  insect 
  is 
  an 
  aeronaut. 
  

   For 
  want 
  of 
  space 
  we 
  did 
  not 
  discuss 
  what 
  had 
  been 
  done 
  by 
  others 
  in 
  

   this 
  direction, 
  nor 
  did 
  we 
  describe 
  the 
  mode 
  of 
  distribution 
  of 
  these 
  air- 
  

   sacs 
  in 
  other 
  insects. 
  

  

  These 
  air-sacs 
  were 
  first 
  noticed 
  by 
  Swammerdam, 
  and 
  afterward 
  by 
  

   Sir 
  John 
  Hunter. 
  Swammerdam, 
  a 
  Dutch 
  naturalist, 
  whose 
  famous 
  

   work 
  entitled 
  The 
  Book 
  of 
  Nature, 
  appeared 
  at 
  Leyden 
  in 
  1737, 
  first 
  

   described 
  and 
  figured 
  them 
  in 
  a 
  lamellicorn 
  beetle 
  (Geotrupes 
  nasicomis). 
  

   Afterward 
  they 
  were 
  discovered 
  by 
  Sir 
  John 
  Hunter 
  in 
  the 
  bee, 
  and 
  sub- 
  

   sequently 
  Prof. 
  K. 
  Sprengel 
  217 
  discovered 
  them 
  in 
  other 
  insects. 
  They 
  

   were 
  in 
  1828 
  described 
  and 
  illustrated 
  in 
  a 
  very 
  elaborate 
  and 
  detailed 
  

   way 
  by 
  Straus 
  Diirckheim 
  in 
  his 
  great 
  work 
  on 
  the 
  anatomy 
  of 
  the 
  

   cockchafer. 
  218 
  Afterward 
  special 
  attention 
  was 
  paid 
  to 
  them 
  by 
  Marcel 
  

   de 
  Serres, 
  who 
  published 
  a 
  detailed 
  account 
  and 
  figures 
  of 
  the 
  air-tubes 
  

   and 
  sacs 
  or 
  vesicles 
  of 
  a 
  grasshopper 
  (Truxalis 
  nasutus). 
  Marcel 
  de 
  

   Serres's 
  figure 
  is 
  truer 
  to 
  nature 
  than 
  that 
  of 
  L. 
  Dufour, 
  published 
  in 
  his 
  

   work 
  on 
  the 
  anatomy 
  of 
  the 
  Orthoptera, 
  219 
  &c, 
  and 
  show 
  well 
  the 
  great 
  

   number 
  of 
  these 
  air-sacs 
  as 
  seen 
  in 
  a 
  dorsal 
  view 
  of 
  the 
  insect. 
  The 
  

   English 
  anatomist, 
  G. 
  Newport, 
  has 
  also 
  described 
  and 
  figured 
  the 
  air- 
  

   sacs 
  in 
  the 
  abdomen 
  of 
  the 
  male 
  bumble-bee 
  in 
  the 
  Philosophical 
  Trans- 
  

   actions 
  of 
  the 
  Royal 
  Society 
  of 
  London, 
  1836. 
  

  

  From 
  Newport's 
  article 
  " 
  Insecta," 
  in 
  Todd's 
  Cyclopaedia 
  of 
  Anatomy 
  

   and 
  Physiology, 
  we 
  take 
  the 
  following 
  statements 
  regarding 
  the 
  distri- 
  

   bution 
  of 
  these 
  sacs 
  in 
  different 
  insects. 
  

  

  These 
  air-sacs 
  are 
  found 
  most 
  developed 
  in 
  bees, 
  wasps, 
  &c. 
  (Hymen- 
  

   optera), 
  moths 
  and 
  butterflies, 
  flies 
  (Diptera), 
  and 
  some 
  beetles 
  and 
  some 
  

   bugs 
  (Hemiptera), 
  though 
  in 
  the 
  immature 
  or 
  larval 
  state 
  of 
  all 
  these 
  

   insects 
  there 
  is 
  not 
  the 
  slightest 
  trace 
  of 
  them. 
  They 
  thus 
  do 
  not 
  occur 
  

  

  217 
  Commentariu3 
  de 
  partibus 
  quibua 
  insocta 
  spiritus 
  ducunt. 
  Lipsiffi, 
  1815. 
  

  

  218 
  Consid6rationa 
  g6neralea 
  aur 
  l'Anatomio 
  comparee 
  des 
  Animaux 
  artioul6a. 
  Par 
  Heroule 
  Straus- 
  

   Diirckheim. 
  Paria, 
  1828. 
  

  

  219 
  Rockerckea 
  anatomiquea 
  ot 
  phyaiologiques 
  sur 
  lea 
  Orthopterea, 
  lea 
  nyin6nopteres 
  et 
  les 
  Nevrop- 
  

   tdres 
  ; 
  par 
  M. 
  L6on 
  Dufour, 
  M6moires 
  Math6matiquoa 
  des 
  Savants 
  etrangera, 
  Paris, 
  1841. 
  

  

  