﻿28 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM 
  vol. 
  108 
  

  

  irregularly 
  rounded, 
  lateral 
  pair 
  (It) 
  narrow 
  and 
  evenly 
  rounded; 
  an- 
  

   tennal 
  socket 
  (an, 
  fig. 
  9, 
  e) 
  circular, 
  minute, 
  traces 
  of 
  sensilla 
  scarcely 
  

   visible 
  under 
  72-power 
  magnification; 
  labrum 
  membranous 
  except 
  

   mesally 
  and 
  at 
  lateral 
  extremities, 
  strongly 
  bilobed, 
  each 
  lobe 
  bearing 
  

   two 
  small 
  setae 
  about 
  equidistant 
  from 
  center 
  and 
  a 
  minute 
  seta 
  near 
  

   anteromesal 
  margin 
  ; 
  exposed 
  apical 
  fourth 
  of 
  overlapping 
  mandibles 
  

   triangular, 
  the 
  apex 
  sharply 
  acute, 
  about 
  seven 
  sharp 
  teeth 
  ; 
  approxi- 
  

   mate 
  basal 
  third 
  of 
  each 
  mandible 
  exposed 
  near 
  end 
  of 
  epistoma, 
  bear- 
  

   ing 
  a 
  single, 
  minute 
  seta 
  ; 
  a 
  long 
  tapering 
  apodeme 
  extending 
  dorso- 
  

   laterally 
  within 
  head 
  capsule; 
  maxillary 
  sclerome 
  (mxs) 
  anterior 
  to 
  

   base 
  of 
  mandible, 
  shaped 
  as 
  illustrated 
  ; 
  labial 
  sclerome 
  (labs) 
  an 
  ir- 
  

   regular, 
  incomplete 
  circle. 
  

  

  Abdomen 
  with 
  10 
  apparent 
  segments; 
  spiracles 
  located 
  as 
  in 
  fifth 
  

   instar 
  ; 
  entire 
  dorsal 
  area 
  glabrous 
  ; 
  venter 
  of 
  prothorax 
  and 
  cervical 
  

   region 
  bearing 
  minute 
  asperities 
  ; 
  dorsal 
  and 
  lateral 
  integument 
  ap- 
  

   pearing 
  as 
  if 
  covered 
  with 
  closely 
  appressed 
  scales 
  (see 
  later 
  descrip- 
  

   tion 
  of 
  exuviae) 
  ; 
  eight 
  abdominal 
  segments 
  with 
  ventral, 
  transverse 
  

   groups 
  of 
  small 
  platelets 
  ; 
  hold-fast 
  organ 
  at 
  posterior 
  margin 
  of 
  seg- 
  

   ment 
  10, 
  transverse, 
  weakly 
  crescent-shaped, 
  with 
  short 
  membranous 
  

   flap 
  extending 
  posteriorly. 
  

  

  Coloration: 
  General 
  color 
  dark 
  blackish-brown; 
  ventral 
  region 
  

   (unstippled 
  areas 
  on 
  fig. 
  9, 
  e, 
  /) 
  unpigmented; 
  a 
  white 
  middorsal 
  line 
  

   (where 
  split 
  occurs 
  at 
  subsequent 
  molt) 
  extending 
  entire 
  length 
  of 
  

   body 
  ; 
  head 
  considerably 
  darker 
  than 
  thorax 
  or 
  abdomen 
  ; 
  region 
  of 
  

   frons 
  lighter 
  colored 
  than 
  main 
  epicranial 
  region, 
  two 
  darker 
  pig- 
  

   mented 
  spots 
  (ps) 
  anterior 
  to 
  median 
  tubercles, 
  a 
  wide 
  longitudinal 
  

   white 
  stripe 
  on 
  frons, 
  interrupted 
  on 
  anterior 
  portion 
  of 
  vertex 
  and 
  

   resumed 
  as 
  narrow 
  line 
  on 
  occiput; 
  labrum 
  unpigmented 
  except 
  at 
  

   lateral 
  extremities, 
  on 
  a 
  slender 
  transverse 
  basal 
  median 
  sclerite, 
  and 
  

   mesally 
  at 
  the 
  junction 
  of 
  the 
  lobes; 
  mandibles 
  and 
  scleromes 
  of 
  max- 
  

   illae 
  and 
  labium 
  pigmented 
  with 
  brown 
  as 
  illustrated. 
  Abdomen 
  

   with 
  paired 
  unpigmented 
  spots 
  dorsad 
  of 
  spiracles 
  3 
  to 
  8, 
  and 
  in 
  a 
  

   similar 
  position 
  on 
  abdominal 
  segment 
  9 
  (which 
  bears 
  no 
  spiracle) 
  ; 
  

   transversely 
  grouped 
  platelets 
  of 
  ventral 
  surface 
  pale 
  brown, 
  also 
  clos- 
  

   ing 
  sclerites 
  of 
  hold-fast 
  organ 
  and 
  immediately 
  adjacent 
  membrane. 
  

  

  Measurements 
  (in 
  millimeters) 
  : 
  Length 
  of 
  body 
  5.7; 
  greatest 
  

   width 
  of 
  body 
  2.2 
  ; 
  greatest 
  width 
  of 
  head 
  capsule 
  1.4. 
  

  

  Comments: 
  Slide-mounted 
  preparations 
  of 
  the 
  cast 
  skin 
  of 
  the 
  

   fourth 
  instar 
  from 
  Falls 
  Church, 
  Va., 
  permitted 
  structures 
  to 
  be 
  

   observed 
  in 
  much 
  greater 
  magnification 
  than 
  was 
  possible 
  with 
  the 
  

   preserved 
  alcoholic 
  larva 
  from 
  Fuguay, 
  N. 
  C. 
  While 
  no 
  significant 
  

   differences 
  in 
  these 
  individual 
  fourth 
  stage 
  larvae 
  apparently 
  occur, 
  

   it 
  is 
  important 
  that 
  the 
  features 
  illustrated 
  and 
  described 
  be 
  attributed 
  

   to 
  the 
  correct 
  specimens. 
  

  

  