﻿HELEID 
  MIDGES, 
  GENUS 
  STILOBEZZIA 
  — 
  WIRTH 
  83 
  

  

  Description. 
  — 
  Female: 
  Length 
  1.5 
  mm., 
  wing 
  1.3 
  mm. 
  by 
  0.5 
  mm. 
  

   Head 
  shining 
  brown, 
  clypeus 
  and 
  antenna! 
  pedicel 
  yellowish, 
  antennal 
  

   flagellum 
  and 
  palpi 
  dusky. 
  Thorax 
  polished 
  brown, 
  mesonotum 
  with 
  

   sparse 
  black 
  hah's 
  in 
  rows 
  ; 
  scutellum 
  with 
  four 
  marginal 
  hairs. 
  Pleura, 
  

   coxae, 
  midfemur, 
  hind 
  femur, 
  and 
  tibiae 
  dusky, 
  yellowish 
  brown; 
  all 
  

   of 
  forelegs, 
  midtarsus, 
  and 
  hind 
  tarsus 
  lighter 
  yellowish. 
  Proportions 
  

   of 
  segments 
  of 
  hind 
  leg 
  as 
  in 
  table 
  1 
  ; 
  basi 
  tarsi 
  unspined; 
  fifth 
  segment 
  

   with 
  a 
  pair 
  of 
  black 
  ventral 
  batonnets 
  near 
  base; 
  claws 
  slender 
  and 
  

   unequal, 
  normal 
  on 
  forelegs 
  and 
  midlegs 
  with 
  outer 
  claw 
  as 
  long 
  as 
  

   fifth 
  segment, 
  the 
  inner 
  a 
  third 
  as 
  long, 
  on 
  hind 
  legs 
  with 
  fifth 
  segment 
  

   half 
  as 
  long 
  and 
  claws 
  only 
  a 
  fourth 
  as 
  long 
  as 
  on 
  forelegs 
  and 
  midlegs. 
  

  

  Wings 
  grayish 
  hyaline, 
  without 
  macro 
  trichiae, 
  anterior 
  veins 
  brown- 
  

   ish 
  yellow. 
  First 
  radial 
  cell 
  a 
  fourth 
  as 
  long 
  as 
  second, 
  latter 
  to 
  five- 
  

   eighths 
  wing 
  length 
  ; 
  vein 
  R4+5 
  on 
  distal 
  half 
  of 
  second 
  radial 
  ceU 
  with 
  

   an 
  oval 
  beadlike 
  swelling; 
  cross 
  vein 
  r-m 
  short, 
  petiole 
  of 
  media 
  about 
  

   three 
  times 
  as 
  long 
  as 
  crossvein. 
  Halteres 
  brown. 
  Abdomen 
  shining 
  

   brown, 
  very 
  convex 
  dorsally 
  and 
  somewhat 
  petiolate 
  at 
  base. 
  

  

  Male: 
  Ninth 
  sternite 
  a 
  slender 
  anterior 
  band, 
  the 
  posterior 
  mem- 
  

   brane 
  spiculate; 
  ninth 
  tergite 
  rounded, 
  the 
  apicolateral 
  lobes 
  reduced. 
  

   Basistyle 
  broad, 
  with 
  a 
  large 
  triangular, 
  flattened, 
  sclerotized 
  lobe 
  

   about 
  midway 
  of 
  mesal 
  margin; 
  dististyle 
  nearly 
  as 
  long 
  as 
  basistyle, 
  

   incurved, 
  gradually 
  tapered 
  to 
  slender 
  apex. 
  Aedeagus 
  with 
  a 
  pair 
  of 
  

   slightly 
  oblique, 
  long, 
  very 
  slender, 
  sclerotized 
  bars. 
  Parameres 
  with 
  

   basal 
  knoblike 
  apodemes 
  fused 
  with 
  anteromesal 
  margins 
  of 
  inner 
  

   lobes 
  of 
  basistyles, 
  with 
  slender, 
  long, 
  curved, 
  sicklelike 
  posterior 
  

   blades. 
  

  

  Types.— 
  USNM 
  60967, 
  holotype, 
  9, 
  and 
  allotype, 
  Falls 
  Church, 
  

   Virginia, 
  July 
  4, 
  1950, 
  Wirth. 
  

  

  Remarks. 
  — 
  This 
  species 
  is 
  very 
  similar 
  to 
  *S'. 
  (S.) 
  antennalis 
  (Coquil- 
  

   lett), 
  but 
  the 
  highly 
  modified 
  posterior 
  branch 
  of 
  the 
  radius 
  and 
  hind 
  

   fifth 
  tarsal 
  segment 
  and 
  claws 
  are 
  quite 
  distinctive. 
  The 
  West 
  

   African 
  species 
  S. 
  limnophila 
  Ingram 
  and 
  Macfie, 
  1922, 
  is 
  very 
  similar 
  

   in 
  coloration 
  and 
  in 
  the 
  structure 
  of 
  the 
  male 
  genitalia, 
  but 
  since 
  the 
  

   female 
  is 
  unloiown, 
  the 
  wing 
  and 
  tarsal 
  features 
  cannot 
  be 
  compared 
  

   with 
  those 
  of 
  sybleae. 
  Parabezzia 
  poikiloptera 
  Ingram 
  and 
  Macfie, 
  

   1922, 
  from 
  West 
  Africa, 
  which 
  is 
  a 
  Stilobezzia 
  of 
  the 
  subgenus 
  Eukrai- 
  

   ohelea, 
  has 
  a 
  remarkable 
  thickening 
  of 
  the 
  radius 
  almost 
  exactly 
  like 
  

   that 
  of 
  sybleae, 
  indicating 
  that 
  this 
  character 
  is 
  not 
  just 
  an 
  aberration. 
  

   This 
  species 
  is 
  named 
  for 
  my 
  wife, 
  Syble 
  Austin 
  Wirth. 
  

  

  17. 
  Stilobezzia 
  {Stilobezzia) 
  thomsenae, 
  new 
  species 
  

  

  Figure 
  12, 
  a 
  

  

  Diagnostic 
  characters. 
  — 
  Very 
  closely 
  related 
  to, 
  and 
  almost 
  indis- 
  

   tinguishable 
  from, 
  bulla 
  Thomsen, 
  except 
  for 
  the 
  very 
  characteristic 
  

   male 
  genitaha. 
  

  

  