﻿NEARCTIC 
  PERISCELIDAE 
  — 
  STURTEVANT 
  559 
  

  

  is 
  not 
  consistent 
  with 
  the 
  hypothesis 
  that 
  they 
  are 
  teneral. 
  However, 
  

   through 
  the 
  kindness 
  of 
  Mr. 
  Sabrosky 
  I 
  have 
  seen 
  a 
  mated 
  pair 
  

   collected 
  at 
  Lake 
  Drummond, 
  Va. 
  (H. 
  S. 
  Barber, 
  June 
  8-11, 
  1905), 
  

   in 
  which 
  the 
  male 
  has 
  the 
  typical 
  pattern 
  of 
  wing 
  clouds 
  while 
  the 
  

   female 
  has 
  hyaline 
  wings. 
  It 
  seems 
  likely 
  that 
  we 
  are 
  concerned 
  here 
  

   with 
  dimorphism 
  of 
  a 
  single 
  species, 
  rather 
  than 
  with 
  two 
  species. 
  

   Mr. 
  Sabrosky 
  reports 
  that 
  the 
  other 
  specimens 
  listed 
  above 
  in 
  the 
  

   U. 
  S. 
  National 
  Museum 
  collection 
  all 
  have 
  the 
  typical 
  wing 
  pattern. 
  

   C. 
  nebulosa 
  is 
  variable 
  in 
  color. 
  In 
  some 
  specimens 
  the 
  legs 
  are 
  

   wholly 
  yellow, 
  except 
  that 
  the 
  terminal 
  segments 
  of 
  all 
  tarsi 
  are 
  

   darkened. 
  In 
  others 
  there 
  is 
  more 
  or 
  less 
  darkening 
  of 
  the 
  apical 
  

   portions 
  of 
  the 
  second 
  and 
  third 
  femora, 
  which 
  in 
  some 
  cases 
  are 
  as 
  

   dark 
  as 
  in 
  the 
  single 
  specimen 
  of 
  imitata. 
  The 
  leg 
  color 
  is 
  not 
  corre- 
  

   lated 
  with 
  the 
  clouding 
  of 
  the 
  wings, 
  and 
  is 
  less 
  easily 
  used 
  for 
  a 
  sharp 
  

   classification 
  into 
  distinct 
  groups 
  of 
  individuals, 
  since 
  intermediates 
  

   occur. 
  

  

  Cyamops 
  imitata, 
  new 
  species 
  

  

  Female. 
  Subshining 
  black. 
  Orbits 
  silvery; 
  antennae 
  browTiish. 
  

   Legs, 
  including 
  coxae, 
  yellow 
  except 
  brown 
  to 
  black 
  first 
  tibiae 
  and 
  

   tarsi, 
  apical 
  halves 
  of 
  second 
  and 
  third 
  femora, 
  and 
  apices 
  of 
  second 
  

   and 
  third 
  tarsi. 
  Palpi 
  and 
  proboscis 
  yeUow. 
  Knob 
  of 
  haltere 
  white. 
  

   Wing 
  clouded, 
  with 
  a 
  hyaline 
  anterior 
  border 
  that 
  includes 
  costal 
  and 
  

   marginal 
  cells 
  and 
  anterior 
  half 
  of 
  submarginal, 
  except 
  that 
  the 
  apical 
  

   portion 
  of 
  the 
  latter 
  is 
  wholly 
  clouded 
  distal 
  to 
  a 
  point 
  midway 
  between 
  

   the 
  ends 
  of 
  second 
  and 
  third 
  veins. 
  

  

  Arista 
  with 
  8 
  or 
  9 
  long 
  dorsal 
  branches 
  and 
  2 
  or 
  3 
  distal 
  ventral 
  

   ones; 
  the 
  6 
  or 
  7 
  proximal 
  dorsal 
  branches 
  are 
  themselves 
  bifid 
  beyond 
  

   their 
  middle. 
  One 
  vibrissa 
  ; 
  posterior 
  to 
  it 
  are 
  two 
  downward-pointing, 
  

   long 
  bristles. 
  Clypeus 
  evident, 
  small. 
  A 
  large 
  proclinate 
  orbital 
  

   and 
  a 
  smaller 
  reclinate 
  one; 
  no 
  ocellars 
  or 
  postverticals; 
  a 
  single 
  

   (divergent) 
  vertical. 
  Face 
  narrowed 
  by 
  the 
  eyes 
  below 
  the 
  antennae. 
  

   A 
  single 
  posterior 
  dorsocentral 
  ; 
  hairs 
  on 
  mesonotum 
  sparse, 
  not 
  in 
  

   regular 
  rows; 
  one 
  supra-alar; 
  one 
  post-alar; 
  no 
  humerals; 
  two 
  noto- 
  

   pleurals; 
  mesopleura 
  bare; 
  one 
  conspicuous 
  sternopleural 
  ; 
  a 
  single 
  

   (apical) 
  pair 
  of 
  convergent 
  scutellars; 
  no 
  preapicals 
  on 
  tibiae; 
  a 
  long 
  

   apical 
  on 
  third 
  tibia. 
  Abdomen 
  flattened. 
  

  

  Second 
  and 
  third 
  costal 
  sections 
  nearly 
  equal; 
  last 
  section 
  fourth 
  

   vein 
  about 
  2.3 
  times 
  penultimate 
  section. 
  Third 
  and 
  fourth 
  veins 
  

   distinctly 
  divergent 
  apicaUy. 
  A 
  conspicuous, 
  erect 
  bristle 
  arising 
  

   from 
  costa 
  near 
  its 
  base. 
  

  

  Length, 
  2.5 
  mm. 
  

  

  Type 
  (USNM 
  61474) 
  collected 
  at 
  La 
  Fayette, 
  Ind., 
  July 
  6, 
  1915 
  

   (J. 
  M. 
  Aldrich). 
  

  

  