﻿250 
  PROF. 
  M. 
  BEZZI. 
  

  

  Ocneros 
  bigemmaius, 
  sp. 
  nov. 
  (PL 
  xviii, 
  fig. 
  2). 
  

  

  Very 
  like 
  the 
  }:>receding 
  species, 
  but 
  distinguished 
  by 
  its 
  larger 
  size, 
  and 
  the 
  

   different 
  pattern 
  of 
  the 
  thorax 
  and 
  wings. 
  

  

  $. 
  Length 
  of 
  body 
  5*5 
  mm. 
  ; 
  of 
  ovipositor 
  1 
  mm. 
  ; 
  of 
  wings 
  6 
  mm. 
  

  

  Head, 
  its 
  appendages 
  and 
  bristles 
  exactly 
  as 
  in 
  the 
  preceding 
  species 
  ; 
  the 
  two 
  

   occipital 
  black 
  spots 
  are 
  broader, 
  shaped 
  as 
  a 
  triangular 
  patch, 
  the 
  outer 
  corner 
  

   of 
  which 
  does 
  not 
  reach 
  the 
  border 
  of 
  the 
  eyes 
  ; 
  there 
  are 
  besides 
  two 
  approximated 
  

   black 
  stripes 
  above 
  the 
  neck, 
  directed 
  towards 
  the 
  vertex, 
  wanting 
  in 
  0. 
  undatus. 
  

   Thorax 
  and 
  scutellum, 
  and 
  their 
  pubescence 
  and 
  bristles, 
  exactly 
  as 
  in 
  the 
  preceding 
  

   species 
  ; 
  there 
  is 
  also 
  an 
  equally 
  narrow, 
  black, 
  notopleural 
  stripe 
  in 
  continuation 
  

   of 
  the 
  occipital 
  one, 
  and 
  therefore 
  there 
  is 
  the 
  same 
  striking 
  contrast 
  with 
  the 
  

   whitish 
  pleurae 
  ; 
  the 
  interior 
  stripe 
  is 
  however 
  much 
  broader 
  and 
  ends 
  at 
  the 
  suture, 
  

   but 
  is 
  continued 
  beyond 
  it 
  with 
  a 
  broad 
  stripe 
  on 
  the 
  dorsocentral 
  lines, 
  extending 
  

   nearly 
  to 
  the 
  lateral 
  edges 
  of 
  the 
  scutellum. 
  The 
  mesophragma 
  is 
  shining 
  reddish, 
  

   brownish 
  fuscous 
  on 
  the 
  sides, 
  like 
  the 
  postscutellum. 
  Halteres 
  and 
  squamulae 
  

   as 
  in 
  0. 
  undatus. 
  Abdomen 
  more 
  elongate, 
  shining 
  reddish 
  ; 
  the 
  three 
  terminal 
  

   segments 
  more 
  broadly 
  black 
  on 
  the 
  sides 
  and 
  middle 
  ; 
  bristles 
  black 
  ; 
  venter 
  

   darker 
  ; 
  ovipositor 
  shining 
  black, 
  with 
  blackish 
  pubescence. 
  Legs 
  as 
  in 
  the 
  

   preceding 
  ; 
  front 
  femora 
  with 
  only 
  three 
  rather 
  thin 
  and 
  yellowish 
  bristles 
  on 
  the 
  

   apical 
  half 
  beneath. 
  Wings 
  as 
  in 
  0. 
  undatus, 
  but 
  with 
  the 
  following 
  differences 
  : 
  

   (a) 
  at 
  base 
  of 
  the 
  stigma 
  there 
  is 
  a 
  broad 
  whitish-hyaline 
  spot, 
  extending 
  below 
  

   to 
  the 
  first 
  longitudinal 
  vein 
  ; 
  (b) 
  the 
  whitish 
  hyaline 
  spot 
  beyond 
  the 
  stigma 
  has 
  

   the 
  shape 
  of 
  an 
  oblique 
  band, 
  which 
  goes 
  from 
  the 
  end 
  of 
  the 
  first 
  vein 
  across 
  the 
  

   middle 
  of 
  the 
  marginal 
  cell 
  to 
  the 
  second 
  vein 
  ; 
  (c) 
  there 
  is 
  no 
  trace 
  of 
  the 
  hyaline 
  

   basal 
  dot 
  of 
  the 
  first 
  posterior 
  cell 
  ; 
  (d) 
  the 
  lower 
  border 
  of 
  the 
  fuscous 
  part 
  is 
  more 
  

   irregular, 
  showing 
  a 
  blackish 
  tooth 
  in 
  the 
  middle 
  of 
  the 
  upper 
  border 
  of 
  the 
  third 
  

   posterior 
  cell, 
  and 
  another 
  more 
  elongate 
  tooth 
  on 
  the 
  outer 
  inferior 
  angle 
  of 
  the 
  

   discoidal 
  cell, 
  reaching 
  the 
  hind 
  border 
  of 
  the 
  wing 
  along 
  the 
  fifth 
  longitudinal 
  

   vein 
  ; 
  in 
  the 
  second 
  posterior 
  cell 
  the 
  border 
  of 
  the 
  fuscous 
  part 
  forms 
  a 
  straight 
  

   line, 
  which 
  has 
  no 
  indentations 
  or 
  projections 
  (or 
  only 
  a 
  little 
  so 
  beyond 
  the 
  fourth 
  

   vein), 
  the 
  cell 
  being 
  thus 
  mainly 
  hyaline 
  ; 
  along 
  the 
  middle 
  of 
  the 
  anal 
  cell 
  there 
  

   is 
  also 
  a 
  subhyaline 
  longitudinal 
  stripe, 
  which 
  is 
  wanting 
  in 
  the 
  preceding 
  

   species. 
  

  

  Type 
  J, 
  a 
  single 
  specimen 
  from 
  British 
  East 
  Africa, 
  Embu, 
  12.xii.1913 
  (G. 
  H. 
  J. 
  

   Or 
  de-Browne). 
  

  

  Ocnerioxa, 
  Speiser, 
  1915. 
  

  

  The 
  species 
  of 
  the 
  present 
  genus 
  show 
  a 
  great 
  resemblance 
  to 
  those 
  of 
  the 
  first 
  

   group 
  (sinuatm, 
  undatus 
  and 
  bigemmatus) 
  of 
  Ocneros 
  ; 
  they 
  have 
  the 
  same 
  

   appearance 
  and 
  the 
  same 
  colour 
  pattern 
  of 
  body 
  and 
  wings, 
  being 
  probably 
  con- 
  

   generic. 
  They 
  can 
  be 
  distinguished 
  only 
  by 
  the 
  third 
  longitudinal 
  vein 
  being 
  

   quite 
  bare, 
  or 
  scarcely 
  setigerous 
  before 
  the 
  small 
  cross- 
  vein 
  only 
  ; 
  and 
  also 
  by 
  

   the 
  bare, 
  non-pubescent 
  arista 
  and 
  by 
  the 
  less 
  developed 
  orbital 
  hairs 
  between 
  

   the 
  fronto- 
  orbital 
  bristles. 
  

  

  In 
  the 
  new 
  material 
  there 
  is 
  the 
  following 
  undescribed 
  form. 
  

  

  