﻿2L4 
  On 
  a 
  new 
  Species 
  of 
  Tabanidae 
  from 
  British 
  Guiana. 
  

  

  colouring 
  and 
  shape 
  of 
  the 
  other 
  species 
  of 
  the 
  genus 
  as 
  she 
  

   restricts 
  it. 
  It 
  is 
  much 
  larger 
  than 
  D. 
  testacea, 
  measuring 
  

   19 
  mm. 
  Its 
  wings 
  are 
  smoky 
  and 
  blotched, 
  whereas 
  in 
  

   D. 
  testacea 
  the 
  wings 
  are 
  hyaline 
  all 
  except 
  three 
  dark 
  spots. 
  

   The 
  tibia 
  of 
  the 
  fore 
  leg 
  is 
  white, 
  but 
  in 
  I). 
  testacea 
  it 
  is 
  

   black. 
  The 
  abdomen 
  is 
  dark 
  brown, 
  in 
  D. 
  testacea 
  a 
  rusty 
  

   brown. 
  

  

  Dichelacera 
  robiginosa, 
  sp. 
  n. 
  

  

  Head 
  broader 
  than 
  the 
  thorax, 
  front 
  and 
  face 
  orange- 
  

   yellow. 
  Eyes 
  large, 
  black 
  with 
  a 
  bronze 
  shimmer, 
  bare. 
  

   Frontal 
  callus 
  a 
  narrow 
  stripe, 
  hardly 
  widening 
  at 
  the 
  base. 
  

   First 
  two 
  joints 
  of 
  the 
  antennae 
  reddish 
  orange, 
  third 
  joint 
  

   reddish 
  brown, 
  its 
  spur 
  reaching 
  to 
  the 
  second 
  ambulation 
  

   and 
  sparsely 
  beset 
  with 
  small 
  bristles 
  on 
  its 
  dorsal 
  surface. 
  

   First 
  three 
  annulations 
  of 
  the 
  third 
  joint 
  dark 
  brown, 
  fourth 
  

   almost 
  black. 
  Palps 
  about 
  as 
  long 
  as 
  antennae, 
  yellow, 
  

   curved, 
  rather 
  thinly 
  tomentose. 
  Proboscis 
  long, 
  brown, 
  

   blackish 
  at 
  the 
  tip. 
  

  

  Thorax 
  and 
  scutellum 
  rusty 
  brown, 
  under 
  surface 
  light 
  

   brown. 
  

  

  Legs 
  : 
  all 
  the 
  femora 
  reddish 
  yellow, 
  as 
  also 
  are 
  the 
  tibia 
  

   and 
  greater 
  part 
  of 
  the 
  first 
  tarsal 
  joint 
  of 
  the 
  second 
  and 
  third 
  

   legs. 
  Tibia 
  of 
  the 
  first 
  leg 
  whitish 
  in 
  its 
  proximal 
  two- 
  

   thirds, 
  dark 
  cinnamon-brown 
  in 
  its 
  distal 
  third. 
  All 
  the 
  

   tarsal 
  segments 
  of 
  the 
  first 
  legs 
  nearly 
  black, 
  the 
  last 
  four 
  

   tarsal 
  segments 
  of 
  the 
  second 
  and 
  third 
  legs 
  dark 
  brown. 
  

  

  Wings 
  much 
  clouded, 
  the 
  veins 
  very 
  dark. 
  Costal 
  cell 
  

   smoky 
  yellow. 
  Between 
  the 
  subcostal 
  and 
  the 
  fifth 
  longi- 
  

   tudinal 
  veins 
  the 
  wing 
  is 
  blotchy 
  and 
  smoky, 
  but 
  the 
  greater 
  

   part 
  of 
  the 
  discal 
  and 
  of 
  the 
  fifth 
  posterior 
  cells 
  and 
  a 
  part 
  of 
  

   the 
  fourth 
  posterior 
  cell 
  are 
  transparent, 
  and 
  the 
  greater 
  part 
  

   of 
  the 
  second 
  basal 
  as 
  well 
  as 
  a 
  distal 
  patch 
  in 
  the 
  marginal 
  

   and 
  second 
  submarginal 
  cells 
  and 
  two 
  narrow 
  streaks 
  in 
  the 
  

   first 
  submarginal 
  cell 
  are 
  translucent. 
  The 
  smoky 
  blotches 
  

   are 
  darkest 
  at 
  the 
  tip 
  of 
  the 
  first 
  longitudinal 
  vein 
  and 
  its 
  

   neighbourhood, 
  round 
  the 
  anterior 
  cross-vein 
  and 
  its 
  neigh- 
  

   bourhood, 
  at 
  the 
  bifurcation 
  of 
  the 
  third 
  longitudinal 
  vein, 
  

   and 
  at 
  the 
  tip 
  of 
  the 
  discal 
  cell. 
  

  

  Abdomen 
  dark 
  brown, 
  each 
  segment 
  from 
  the 
  second 
  to 
  the 
  

   fifth 
  inclusive 
  with 
  a 
  well-defined 
  median 
  triangular 
  yellow 
  

   patch. 
  Under 
  surface 
  light 
  brown. 
  

  

  The 
  specimen 
  that 
  constitutes 
  the 
  type 
  of 
  this 
  species 
  was 
  

   sent 
  to 
  the 
  London 
  School 
  of 
  Tropical 
  Medicine 
  by 
  Dr. 
  K. 
  S. 
  

   Wise, 
  Government 
  Medical 
  Officer, 
  Georgetown, 
  Demerara, 
  

  

  