﻿NEW 
  AND 
  LITTLE-KNOWN 
  MESOPOTAMIAN 
  BLOOD-SUCKING 
  DIPTERA. 
  

  

  277 
  

  

  Family 
  Tabanidae. 
  

  

  Subfamily 
  Pangoniinae. 
  

  

  Genus 
  Silvius, 
  Meigen. 
  

  

  Silvius 
  irritans, 
  Ric. 
  (fig. 
  2). 
  

  

  Silvius 
  irritans, 
  Ricardo, 
  Ann. 
  Mag. 
  Nat. 
  Hist. 
  (7), 
  viii, 
  p. 
  292 
  (1901). 
  

  

  Silvius 
  unicolor, 
  Becker, 
  Ann. 
  Mus. 
  Zool. 
  Acad. 
  Imp. 
  Sc. 
  St. 
  Petersb., 
  xvii, 
  p. 
  588 
  

   (1913). 
  [New 
  synonym]. 
  

  

  One 
  2, 
  Hit, 
  R. 
  Euphrates, 
  vii.1920; 
  one 
  2, 
  Ramadi, 
  R. 
  Euphrates, 
  9.viii.l920, 
  

   " 
  in 
  horse 
  lines 
  " 
  ; 
  a 
  third 
  2. 
  Ramadi, 
  ix.1920 
  : 
  all 
  collected 
  and 
  presented 
  by 
  

   Major 
  A. 
  D. 
  Fraser, 
  who 
  states 
  in 
  a 
  field-note 
  that 
  the 
  " 
  eyes 
  are 
  golden 
  -green, 
  with 
  

   dark 
  brown 
  markings 
  " 
  (fig. 
  2). 
  

  

  The 
  typical 
  series 
  (seven 
  2?) 
  of 
  this 
  species, 
  which 
  is 
  in 
  the 
  British 
  Museum, 
  was 
  

   taken 
  in 
  1884-85 
  in 
  Khorasan, 
  Persia, 
  and 
  in 
  the 
  Hari-rud 
  Valley, 
  Afghanistan, 
  

   by 
  Dr. 
  J. 
  E. 
  T. 
  Aitchison, 
  Naturalist 
  of 
  the 
  Afghan 
  Delimitation 
  Commission, 
  who 
  

   writes 
  (Trans. 
  Linn. 
  Soc, 
  London 
  (2) 
  v, 
  Zool., 
  p. 
  132, 
  1889) 
  : 
  — 
  "Near 
  Mount 
  Do- 
  

   Shakh 
  my 
  ponies 
  were 
  nearly 
  driven 
  mad 
  with 
  the 
  numbers 
  of 
  this 
  very 
  small 
  species 
  ; 
  

   although 
  in 
  ones 
  or 
  twos 
  they 
  did 
  not 
  give 
  much 
  trouble, 
  when 
  in 
  large 
  numbers, 
  as 
  

   I 
  saw 
  them, 
  they 
  were 
  extremely 
  irritating 
  to 
  the 
  cattle, 
  chiefly 
  attacking 
  the 
  head 
  

   and 
  fore 
  legs." 
  

  

  Fig. 
  2. 
  Head 
  of 
  Silvius 
  irritans, 
  Ric, 
  2- 
  from 
  in 
  front, 
  

  

  showing 
  frontal 
  callus, 
  bare 
  flecks 
  or 
  spots 
  near 
  base 
  

  

  of 
  antennae, 
  and 
  eye-markings. 
  

  

  In 
  the 
  case 
  of 
  the 
  typical 
  series 
  of 
  S. 
  irritans, 
  all 
  the 
  specimens 
  belonging 
  to 
  which 
  

   are 
  denuded 
  and 
  snrivelled 
  through 
  having 
  originally 
  been 
  preserved 
  in 
  alcohol, 
  the 
  

   ground-colour 
  of 
  the 
  dorsum 
  of 
  the 
  abdomen 
  is 
  pinkish 
  cinnamon, 
  with 
  conspicuous 
  

   slate-black 
  markings 
  as 
  follows 
  : 
  — 
  a 
  large, 
  rounded, 
  median 
  blotch 
  on 
  the 
  second 
  

   (visible) 
  tergite, 
  not 
  extending 
  to 
  the 
  hind 
  margin, 
  and 
  deep 
  transverse 
  bands 
  on 
  the 
  

   third 
  and 
  three 
  or 
  four 
  following 
  tergites, 
  each 
  band 
  occupying 
  the 
  anterior 
  three- 
  

   fourths 
  of 
  the 
  segment 
  ; 
  in 
  the 
  case 
  of 
  the 
  third 
  (sometimes 
  also 
  in 
  that 
  of 
  the 
  fourth) 
  

   tergite 
  the 
  band 
  may 
  be 
  twice 
  interrupted, 
  so 
  as 
  to 
  form 
  a 
  transverse 
  series 
  of 
  three 
  

   discontinuous 
  blotches 
  ; 
  certain 
  specimens 
  show 
  an 
  ill-defined, 
  dusky, 
  median 
  blotch 
  

   on 
  the 
  first 
  (visible) 
  tergite, 
  projecting 
  somewhat 
  beyond 
  the 
  hind 
  margin 
  of 
  the 
  

   scutellum. 
  Similar 
  abdominal 
  markings, 
  largely 
  concealed 
  by 
  the 
  coat 
  of 
  pale 
  olive- 
  

   buff 
  pollen 
  with 
  which 
  head 
  and 
  body 
  in 
  this 
  species 
  are 
  normally 
  covered, 
  are 
  

  

  