﻿306 
  REPORT 
  UNITED 
  STATES 
  ENTOMOLOGICAL 
  COMMISSION. 
  

  

  are 
  inserted 
  at 
  the 
  posterior 
  end 
  on 
  the 
  side 
  of 
  each 
  segment 
  (bseno- 
  

   mere), 
  as 
  the 
  coxae 
  are 
  widely 
  separated 
  by 
  the 
  very 
  large 
  and 
  broad 
  

   sterhites. 
  

  

  Fropleurites. 
  (PI. 
  XXIY, 
  fig. 
  1.) 
  These 
  are 
  well 
  developed. 
  The 
  

   episternum 
  is 
  horizontal, 
  flat, 
  subtriangular, 
  narrow, 
  reduced 
  to 
  a 
  

   point 
  before 
  reaching 
  the 
  coxa. 
  A 
  wedge-shaped, 
  triangular 
  sclerite 
  is 
  

   wedged 
  in 
  between 
  it 
  and 
  the 
  stern 
  ite 
  (this 
  may 
  be 
  regarded 
  as 
  the 
  sub- 
  

   episternum, 
  though 
  possibly 
  the 
  trochantine, 
  as 
  the 
  coxa 
  is 
  apparently 
  

   entire, 
  and 
  there 
  is 
  otherwise 
  no 
  trochantine 
  to 
  be 
  found). 
  

  

  The 
  epimerum 
  forms 
  the 
  upper 
  part 
  of 
  the 
  pleurum, 
  and 
  is 
  scale-like, 
  

   oblong-oval; 
  in 
  front 
  it 
  is 
  narrow, 
  and 
  ends 
  at 
  the 
  anterior 
  margin 
  of 
  

   the 
  notum. 
  The 
  posterior 
  or 
  upper 
  end 
  of 
  the 
  epimerum 
  is 
  free, 
  rounded, 
  

   scale-like, 
  as 
  it 
  covers 
  the 
  prothoracic 
  stigma. 
  

  

  The 
  coxa 
  is 
  cylindrical, 
  shorter 
  than 
  broad. 
  I 
  can 
  perceive 
  no 
  suture 
  

   in 
  it, 
  and 
  think 
  the 
  trochantine 
  is 
  obsolete. 
  

  

  Mesopleurites. 
  (Fig. 
  2.) 
  These 
  sclerites. 
  repeat 
  the 
  form 
  of 
  the 
  pro- 
  

   pleurites. 
  The 
  segment 
  (bsenomere) 
  is 
  not 
  so 
  long, 
  and 
  the 
  sclerites 
  

   are 
  a 
  little 
  more 
  horizontal. 
  The 
  epimerum 
  is 
  more 
  regularly 
  oblong- 
  

   oval, 
  with 
  a 
  deep 
  crease 
  or 
  fold 
  below 
  the 
  middle, 
  which 
  extends 
  ob- 
  

   liquely 
  from 
  near 
  the 
  coxa 
  to 
  the 
  front 
  edge 
  of 
  the 
  epimerum. 
  

  

  The 
  episternum 
  is 
  in 
  this 
  segment, 
  as 
  in 
  the 
  preceding 
  one, 
  divided 
  

   into 
  two 
  pieces 
  ; 
  the 
  sur-episternum 
  is 
  very 
  small 
  and 
  situated 
  in 
  the 
  

   same 
  plane 
  as 
  and 
  on 
  the 
  side 
  of 
  the 
  anterior 
  end 
  of 
  the 
  sternum. 
  The 
  

   triangular 
  sub-episternum 
  is 
  more 
  oblique 
  than 
  in 
  the 
  propleurum. 
  The 
  

   coxa 
  is 
  smaller 
  than 
  in 
  the 
  pro 
  thorax. 
  

  

  Metapleurites. 
  (Fig. 
  3.) 
  The 
  structure 
  of 
  this 
  region 
  is 
  very 
  remark- 
  

   able, 
  as 
  compared 
  with 
  that 
  of 
  other 
  Phyloptera. 
  The 
  episternum 
  is 
  

   simple, 
  not 
  subdivided 
  as 
  in 
  the 
  pro- 
  and 
  mesopleurum, 
  but 
  represented 
  

   by 
  an 
  acutely 
  triangular 
  sclerite, 
  the 
  base 
  of 
  which 
  lies 
  next 
  to 
  the 
  

   coxa, 
  the 
  acute 
  apex 
  reaching 
  only 
  two 
  -thirds 
  the 
  way 
  to 
  the 
  front 
  of 
  

   the 
  sternum. 
  This 
  reduction 
  in 
  the 
  size 
  of 
  the 
  episternal 
  elements 
  is 
  due 
  

   to 
  the 
  increase 
  in 
  size 
  of 
  the 
  sternum 
  below 
  and 
  the 
  epimerum 
  above. 
  

  

  The 
  epimerum 
  is 
  enormously 
  developed, 
  extending 
  from 
  the 
  insertion 
  

   of 
  the 
  hind 
  wings 
  (which 
  is 
  very 
  near 
  that 
  of 
  the 
  anterior 
  pair) 
  back 
  

   nearly 
  to 
  the 
  middle 
  of 
  the 
  second 
  abdominal 
  segment 
  ; 
  it 
  thus 
  forms 
  

   the 
  side 
  of 
  about 
  half 
  the 
  entire 
  thorax; 
  in 
  situation 
  it 
  is 
  horizontal, 
  

   its 
  sides 
  vertical, 
  but 
  in 
  front 
  next 
  to 
  the 
  mesocoxse 
  and 
  sternum 
  it 
  

   rounds 
  down 
  and 
  under, 
  becoming 
  ventral.^ 
  (This 
  is 
  a 
  most-novel 
  mod- 
  

   ification 
  of 
  the 
  met-episternum, 
  and 
  as 
  unique 
  as 
  the 
  modification 
  of 
  the 
  

   mes-episternum 
  in 
  the 
  Odonata.) 
  

  

  Coxae 
  longer 
  than 
  in 
  the 
  mesothorax, 
  and 
  soldered 
  to 
  the 
  sternum. 
  

  

  Sternum. 
  

  

  The 
  sternal 
  elements 
  are 
  in 
  Forficulidae 
  remarkably 
  large 
  and 
  broad, 
  

   the 
  species 
  being 
  essentially 
  runners. 
  

   The 
  prosternum 
  is 
  subdivided 
  into 
  a 
  single, 
  large 
  intercoxal 
  plate, 
  

  

  