﻿THE 
  INSECTS 
  OE 
  NEW 
  JERSEY. 
  19 
  

  

  CHAPTER 
  H. 
  

  

  The 
  system 
  used 
  in 
  this 
  Hst 
  is 
  practically 
  the 
  same 
  as 
  that 
  of 
  

   the 
  previous 
  edition, 
  and 
  it 
  may 
  be 
  well 
  to 
  briefly 
  state 
  the 
  char- 
  

   acters 
  of 
  the 
  orders 
  as 
  used 
  here. 
  

  

  I 
  assume 
  that 
  the 
  primitive 
  insect 
  from 
  which 
  all 
  the 
  types 
  now 
  

   existing 
  have 
  descended 
  was 
  a 
  small, 
  soft-bodied 
  creature 
  living 
  

   in 
  moist 
  earth 
  or 
  mud 
  along 
  the 
  banks 
  of 
  bodies 
  of 
  water. 
  It 
  had 
  

   six 
  true 
  legs, 
  and 
  probably 
  leg-like 
  abdominal 
  appendages, 
  no 
  

   wings, 
  no 
  compound 
  eyes 
  or 
  no 
  eyes 
  at 
  all, 
  and 
  no 
  developed 
  

   breathing 
  system 
  ; 
  taking 
  in 
  oxygen 
  from 
  the 
  surrounding 
  

   moisture 
  through 
  all 
  parts 
  of 
  the 
  skin 
  surface. 
  The 
  head 
  was 
  

   not 
  much 
  differentiated 
  from 
  the 
  rest 
  of 
  the 
  body, 
  and 
  the 
  mouth 
  

   parts 
  were 
  generalized, 
  with 
  three 
  or 
  four 
  pairs 
  of 
  fleshy 
  processes 
  

   from 
  which 
  the 
  jointed 
  and 
  other 
  appendages 
  of 
  the 
  more 
  

   specialized 
  mouth 
  structures 
  developed. 
  These 
  were 
  the 
  Proto- 
  

   thysanura, 
  and 
  creatures 
  not 
  so 
  very 
  difl^erent 
  occur 
  among 
  the 
  

   Thysanura 
  of 
  the 
  present 
  day. 
  The 
  latter, 
  however, 
  have 
  in 
  some 
  

   cases 
  well 
  developed 
  mouth 
  parts, 
  while 
  many 
  live 
  in 
  dry 
  places 
  

   and 
  have 
  a 
  fairly 
  complete 
  tracheal 
  system. 
  There 
  are 
  no 
  distinct 
  

   metamorphoses 
  and 
  the 
  insects 
  are 
  wingless 
  throughout. 
  

  

  Our 
  primitive 
  Thysanurans 
  divided 
  early 
  into 
  two 
  branches 
  

   on 
  mouth 
  structure; 
  some 
  becoming 
  mandibulate 
  or 
  fitted 
  for 
  

   chewing, 
  while 
  others 
  became 
  haustellate, 
  fitted 
  for 
  puncturing 
  

   plant 
  or 
  animal 
  cells, 
  and 
  living 
  on 
  the 
  juices 
  alone. 
  In 
  both 
  

   these 
  branches 
  wings 
  developed, 
  very 
  different 
  in 
  type 
  and 
  yet 
  

   with 
  fundamentally 
  the 
  same 
  scheme 
  of 
  venation. 
  

  

  The 
  little 
  order 
  Thysanoptera 
  has 
  the 
  mouth 
  parts 
  fitted 
  for 
  

   puncturing 
  or 
  scraping 
  the 
  surface 
  so 
  as 
  to 
  get 
  at 
  the 
  plant 
  juices, 
  

   which 
  are 
  then 
  drawn 
  into 
  the 
  body. 
  The 
  wings 
  are 
  long, 
  very 
  

   narrow, 
  frail, 
  not 
  connected, 
  and 
  altogether 
  the 
  structure 
  is 
  

   primitive. 
  Popularly 
  they 
  are 
  known 
  as 
  Thrips, 
  and 
  some 
  of 
  

   them 
  are 
  decidedly 
  injurious 
  to 
  farm 
  crops. 
  

  

  A 
  decided 
  step 
  forward 
  is 
  made 
  in 
  the 
  Rhyngota, 
  in 
  which 
  the 
  

   mouth 
  parts 
  are 
  developed 
  into 
  slender 
  lancets 
  fitted 
  for 
  piercing, 
  

   and 
  are 
  protected 
  by 
  a 
  jointed 
  beak 
  except 
  in 
  the 
  parasitica 
  and 
  

  

  