﻿A 
  NEW 
  AUSTRALIAN 
  SPECIES 
  OF 
  RIOXA. 
  3 
  

  

  arista 
  are 
  closer 
  together 
  on 
  both, 
  sides, 
  forming 
  thus 
  a 
  kind 
  of 
  apical 
  tuft, 
  which 
  is 
  

   not 
  clearly 
  indicated 
  in 
  the 
  female. 
  Palpi 
  broad, 
  yellowish, 
  reddish 
  at 
  the 
  outer 
  

   border, 
  with 
  yellowish 
  hairs 
  and 
  some 
  black 
  bristles 
  ; 
  proboscis 
  dirty 
  yellowish, 
  

   with 
  pale 
  hairs 
  ; 
  the 
  hairs 
  of 
  the 
  lower 
  part 
  of 
  the 
  head 
  are 
  likewise 
  pale 
  yellowish. 
  

   All 
  the 
  cephalic 
  bristles 
  are 
  black, 
  those 
  of 
  the 
  occipital 
  border 
  being 
  numerous 
  and 
  

   pointed 
  ; 
  the 
  postvertical 
  are 
  long 
  ; 
  outer 
  vertical 
  half 
  as 
  long 
  as 
  the 
  inner 
  one 
  ; 
  

   no 
  ocellar 
  ; 
  only 
  a 
  single 
  superior 
  orbital,* 
  the 
  basal 
  one 
  ; 
  only 
  a 
  single 
  inferior 
  

   orbital, 
  the 
  apical 
  one, 
  which 
  is 
  placed 
  very 
  near 
  the 
  antennae, 
  and 
  is 
  rather 
  weak 
  

   and 
  short 
  ; 
  genal 
  bristle 
  well 
  developed, 
  black. 
  

  

  Thorax 
  on 
  the 
  back 
  entirely 
  reddish 
  and 
  rather 
  shining, 
  the 
  very 
  short 
  pubescence 
  

   black 
  and 
  fhe 
  whitish 
  dust 
  very 
  sparse 
  : 
  the 
  humeri, 
  the 
  sides 
  above 
  the 
  notopleural 
  

   line, 
  and 
  a 
  broad 
  postsutural 
  stripe 
  above 
  the 
  root 
  of 
  wings, 
  are 
  of 
  a 
  more 
  yellowish 
  

   colour, 
  but 
  not 
  sharply 
  defined 
  ; 
  along 
  the 
  dorsocentral 
  lines 
  there 
  is 
  sometimes 
  in 
  

   fully 
  coloured 
  specimens 
  a 
  brownish, 
  ill-defined 
  longitudinal 
  stripe 
  ; 
  the 
  two 
  blackish 
  

   spots 
  in 
  front 
  of 
  the 
  scutellum 
  are 
  rounded 
  and 
  lie 
  between 
  the 
  praescutellar 
  and 
  

   inner 
  pair 
  of 
  the 
  posterior 
  supra-alar 
  bristles, 
  not 
  extending 
  in 
  front 
  beyond 
  the 
  

   praescutellar 
  bristles. 
  The 
  pleurae 
  are 
  entirely 
  reddish 
  and 
  shining, 
  quite 
  unspotted, 
  

   even 
  the 
  hypopleural 
  spots 
  being 
  not 
  paler 
  than 
  the 
  surrounding 
  parts 
  ; 
  the 
  short 
  

   hairs 
  are 
  mainly 
  black. 
  Scutellum 
  triangular 
  and 
  of 
  rather 
  large 
  size 
  : 
  it 
  is 
  

   flattened 
  above, 
  with 
  well 
  developed 
  lateral 
  keels 
  ; 
  it 
  is 
  entirely 
  yellowish, 
  but 
  

   on 
  each 
  side 
  there 
  is 
  a 
  triangular 
  blackish 
  or 
  brownish 
  spot 
  in 
  contact 
  with 
  that 
  at 
  

   hind 
  border 
  of 
  the 
  mesonotum 
  ; 
  it 
  is 
  clothed 
  on 
  the 
  sides 
  with 
  short 
  black 
  hairs, 
  

   and 
  bears 
  six 
  equally 
  strong, 
  black 
  bristles, 
  even 
  those 
  of 
  the 
  middle 
  pair 
  being 
  as 
  

   strong 
  as 
  the 
  others, 
  and 
  those 
  of 
  the 
  apical 
  pair 
  being 
  parallel 
  or 
  diverging. 
  Post- 
  

   scutellum 
  and 
  mesophragma 
  shining 
  black 
  (in 
  fully 
  coloured 
  specimens), 
  with 
  a 
  

   narrow, 
  reddish, 
  middle 
  longitudinal 
  stripe. 
  Thoracic 
  chaetotaxy 
  complete 
  ; 
  all 
  

   the 
  bristles 
  are 
  black, 
  even 
  the 
  scapular 
  ones, 
  the 
  middle 
  pair 
  of 
  which 
  is 
  as 
  strong 
  

   as 
  the 
  lateral 
  ones 
  and 
  has 
  its 
  bristles 
  rather 
  distant 
  ; 
  praesutural 
  bristles 
  rather 
  

   weak 
  and 
  short 
  ; 
  dorsocentral 
  bristles 
  placed 
  much 
  behind, 
  about 
  on 
  a 
  level 
  with 
  

   the 
  praescutellar 
  ones 
  ; 
  one 
  strong 
  mesopleural 
  bristle, 
  and 
  2-3 
  more 
  weak 
  ones 
  

   below 
  it 
  ; 
  pteropleural 
  bristle 
  as 
  strong 
  as 
  the 
  sternopleural 
  one. 
  Squamulae 
  and 
  

   halteres 
  whitish, 
  the 
  former 
  with 
  white 
  hairs 
  at 
  the 
  border. 
  

  

  Abdomen 
  elongate, 
  slightly 
  constricted 
  at 
  base, 
  and 
  about 
  as 
  broad 
  as 
  the 
  thorax 
  

   at 
  the 
  end 
  of 
  the 
  second 
  segment 
  ; 
  it 
  is 
  shining 
  reddish, 
  with 
  broad, 
  shining 
  black 
  

   bands 
  at 
  base 
  of 
  segments 
  3-5, 
  the 
  bands 
  being 
  in 
  the 
  female 
  broadly 
  interrupted 
  

   in 
  the 
  middle, 
  while 
  in 
  the 
  male 
  they 
  are 
  entire 
  or 
  nearly 
  so, 
  the 
  last 
  segment 
  being 
  

   entirely 
  black 
  ; 
  the 
  hind 
  borders 
  of 
  segments 
  2-5 
  are 
  pale 
  yellowish 
  with 
  whitish 
  

   dust, 
  thus 
  contrasting 
  strikingly 
  with 
  the 
  black 
  basal 
  bands. 
  Male 
  genitalia 
  black, 
  

   rounded, 
  prominent 
  below 
  ; 
  ovipositor 
  shining 
  black, 
  depressed, 
  with 
  the 
  basal 
  

   segment 
  as 
  long 
  as 
  the 
  last 
  two 
  abdominal 
  segments 
  together. 
  Venter 
  entirely 
  

   reddish-yellow, 
  unspotted. 
  The 
  short 
  abdominal 
  pubescence 
  is 
  black, 
  like 
  the 
  

   bristles 
  at 
  the 
  sides 
  and 
  end 
  ; 
  the 
  two 
  basal 
  segments 
  are 
  clothed 
  with 
  soft, 
  long 
  

   whitish 
  hairs 
  at 
  the 
  sides. 
  

  

  * 
  In 
  the 
  allied 
  genus 
  Ptilona 
  there 
  is 
  likewise 
  but 
  a 
  single 
  s. 
  or., 
  but 
  it 
  is 
  the 
  apical 
  one. 
  

   In 
  the 
  recently 
  described 
  genus 
  Ortaloptera, 
  Edwards 
  (Trans. 
  Zool. 
  Soc, 
  1915, 
  p. 
  419, 
  

   pi. 
  xxxviii, 
  fig. 
  9), 
  from 
  New 
  Guinea, 
  the 
  cephalic 
  chaetotaxy 
  is 
  very 
  like 
  that 
  of 
  the 
  

   present 
  species, 
  while 
  that 
  of 
  the 
  thorax 
  is 
  much 
  more 
  reduced. 
  

  

  (C572) 
  a2 
  

  

  