﻿THE 
  TABANIDAE 
  OF 
  SOUTHERN 
  NY 
  AS 
  ALAND. 
  

  

  309 
  

  

  the 
  wing 
  being 
  uniformly 
  dusky 
  to 
  the 
  edge 
  of 
  the 
  apex. 
  The 
  golden 
  spots 
  on 
  the 
  

   dorsal 
  surface 
  of 
  the 
  abdomen 
  are 
  nearly 
  always 
  smaller 
  than 
  those 
  of 
  T. 
  biguttatus, 
  

   and 
  in 
  specimens 
  from 
  Mlanje 
  are 
  not 
  infrequently 
  evanescent. 
  The 
  females 
  of 
  

   T. 
  corax 
  are 
  interesting 
  in 
  that 
  both 
  a 
  grey 
  and 
  a 
  golden 
  form 
  occur, 
  just 
  as 
  

   in 
  the 
  case 
  of 
  T. 
  biguttatus. 
  

  

  Fig. 
  19. 
  Dorsal 
  view 
  of 
  syphon 
  and 
  anal 
  segment 
  of 
  a 
  young 
  larva 
  of 
  T. 
  corax, 
  Lw., 
  

   showing 
  Graber's 
  organ 
  ; 
  the 
  dotted 
  line 
  shows 
  the 
  position 
  of 
  the 
  anus. 
  

  

  Considerable 
  numbers 
  of 
  the 
  larvae 
  of 
  this 
  species 
  were 
  obtained. 
  Adult 
  

   specimens 
  are 
  very 
  large 
  (from 
  40-45 
  mm. 
  in 
  length) 
  and 
  very 
  distinct, 
  having 
  

   a 
  very 
  thick, 
  rough 
  integument 
  of 
  a 
  dull 
  reddish 
  colour, 
  with 
  a 
  tendency 
  to 
  two 
  

   more 
  definite 
  patches 
  of 
  darker 
  red 
  on 
  the 
  dorsal 
  portions 
  of 
  the 
  last 
  two 
  

   segments. 
  The 
  general 
  coloration 
  appears 
  to 
  be 
  largely 
  due 
  to 
  the 
  presence 
  of 
  

   foreign 
  bodies 
  in 
  the 
  rough 
  skin. 
  The 
  syphon 
  is 
  very 
  short 
  (PL 
  xxvii, 
  fig. 
  9). 
  

   These 
  larvae 
  were 
  most 
  ferocious 
  cannibals 
  in 
  all 
  stages 
  and 
  very 
  troublesome 
  in 
  the 
  

   laboratory, 
  as 
  they 
  seemed 
  to 
  have 
  unlimited 
  powers 
  of 
  wandering 
  about, 
  even 
  over 
  

   dry 
  surfaces. 
  They 
  frequently 
  succeeded 
  in 
  reaching 
  the 
  receptacles 
  in 
  which 
  other 
  

   species 
  were 
  kept, 
  and 
  in 
  destroying 
  the 
  larvae 
  in 
  them. 
  

  

  In 
  the 
  pupal 
  aster 
  the 
  dorsal 
  hooks 
  of 
  the 
  male 
  are 
  somewhat 
  larger 
  than 
  those 
  

   of 
  the 
  female. 
  The 
  dorso-lateral 
  comb 
  is 
  large 
  and 
  composed 
  of 
  very 
  long 
  and 
  

   fine 
  spines. 
  

  

  A 
  number 
  of 
  newly-hatched 
  larvae 
  of 
  this 
  species 
  were 
  obtained 
  from 
  collected 
  

   egg-masses, 
  generally 
  found 
  on 
  reeds 
  overhanging 
  swampy 
  ground. 
  These 
  grew 
  

   very 
  slowly 
  at 
  first. 
  Fig. 
  19 
  is 
  a 
  diagrammatic 
  sketch 
  of 
  the 
  syphon 
  and 
  anal 
  

   segment 
  of 
  one 
  of 
  these 
  young 
  larvae. 
  It 
  shows 
  the 
  peculiar 
  Graber's 
  organ, 
  

   which 
  is 
  such 
  a 
  conspicuous 
  object 
  in 
  most 
  Tabanid 
  larvae 
  when 
  examined 
  in 
  life 
  

   under 
  a 
  lens. 
  This 
  remarkable 
  organ 
  is 
  somewhat 
  tongue-shaped 
  or 
  triangular 
  and 
  

   is 
  attached 
  by 
  fine 
  strands 
  of 
  muscle 
  from 
  each 
  of 
  the 
  three 
  corners, 
  apparently 
  

   to 
  the 
  body 
  wall. 
  It 
  lies 
  above 
  the 
  gut 
  immediately 
  below 
  the 
  dorsal 
  integument, 
  

   and 
  seems 
  to 
  be 
  capable 
  of 
  movement 
  independent 
  of 
  the 
  general 
  body 
  movements. 
  

   This 
  organ 
  contains 
  a 
  number 
  of 
  pairs 
  of 
  small 
  black 
  pyriform 
  bodies, 
  which, 
  as 
  

   Mitzmain 
  has 
  pointed 
  out, 
  seem 
  to 
  increase 
  in 
  number 
  with 
  the 
  age 
  of 
  the 
  

   individual. 
  The 
  organ 
  appears 
  to 
  be 
  more 
  elongated 
  and 
  to 
  contain 
  more 
  pairs 
  

   of 
  these 
  bodies 
  in 
  the 
  Chrysops 
  larvae 
  that 
  I 
  have 
  seen, 
  than 
  in 
  any 
  others. 
  

  

  