﻿THE 
  TABANIDAE 
  OF 
  SOUTHERN 
  NYASALAND. 
  293 
  

  

  The 
  egg-masses 
  of 
  T. 
  cor 
  ax 
  are 
  of 
  the 
  usual 
  Tabanid 
  type, 
  all 
  the 
  individual 
  spindle- 
  

   shaped 
  eggs 
  being 
  laid 
  with 
  their 
  long 
  axes 
  in 
  the 
  same 
  direction. 
  In 
  the 
  cases 
  

   observed, 
  hatching 
  took 
  place 
  about 
  the 
  fifth 
  day, 
  but 
  this 
  would 
  be 
  likely 
  to 
  be 
  

   lengthened 
  or 
  shortened 
  in 
  some 
  cases, 
  according 
  to 
  the 
  temperature. 
  The 
  process 
  

   of 
  hatching 
  is 
  a 
  remarkable 
  one 
  and 
  takes 
  place 
  with 
  surprising 
  suddenness. 
  

   The 
  egg-mass 
  splits 
  in 
  the 
  middle 
  line, 
  following 
  the 
  long 
  axis, 
  and 
  the 
  small 
  larvae 
  

   emerge 
  almost 
  simultaneously, 
  forming 
  a 
  large 
  quasi-viscous 
  drop 
  which 
  falls 
  

   bodily 
  from 
  the 
  reeds, 
  etc., 
  into 
  the 
  water 
  or 
  mud 
  below. 
  

  

  The 
  young 
  larvae, 
  in 
  my 
  experience, 
  grow 
  very 
  slowly 
  at 
  first 
  and 
  differ 
  from 
  

   the 
  later 
  stages 
  in 
  being 
  more 
  active 
  and 
  swimming 
  more 
  freely 
  in 
  water 
  (which 
  they 
  

   do 
  by 
  lashing 
  themselves 
  along 
  the 
  surface). 
  The 
  more 
  mature 
  larvae, 
  especially 
  

   of 
  the 
  larger 
  species, 
  appeared 
  to 
  be 
  principally 
  nocturnal 
  in 
  their 
  habits. 
  Most 
  

   species 
  are, 
  I 
  think, 
  more 
  or 
  less 
  cannibalistic, 
  but 
  this 
  seems 
  to 
  be 
  largely 
  a 
  

   question 
  of 
  the 
  age 
  of 
  the 
  larvae, 
  and 
  the 
  species 
  in 
  which 
  this 
  habit 
  is 
  most 
  marked 
  

   seem 
  to 
  lose 
  it 
  as 
  they 
  become 
  mature. 
  The 
  large 
  larvae, 
  especially 
  those 
  of 
  a 
  

   species 
  like 
  Tabanus 
  corax, 
  are 
  very 
  savage 
  when 
  disturbed 
  and 
  strike 
  at 
  everything 
  

   within 
  reach 
  with 
  their 
  mandibular 
  hooks, 
  which 
  readily 
  penetrate 
  the 
  skin 
  of 
  

   the 
  hand. 
  

  

  With 
  regard 
  to 
  questions 
  of 
  the 
  morphological 
  details 
  of 
  the 
  numerous 
  larvae 
  

   and 
  pupae 
  obtained, 
  I 
  have 
  been 
  much 
  indebted 
  to 
  Mr. 
  James 
  Waterston, 
  of 
  the 
  

   Imperial 
  Bureau, 
  who 
  has 
  given 
  me 
  much 
  assistance 
  on 
  these 
  points 
  and 
  has 
  

   suggested 
  the 
  convenient 
  name 
  " 
  aster 
  " 
  for 
  the 
  group 
  of 
  hooks 
  at 
  the- 
  termination 
  

   of 
  the 
  last 
  segment 
  of 
  the 
  pupa. 
  The 
  form 
  of 
  this 
  differs 
  a 
  good 
  deal 
  in 
  the 
  various 
  

   species, 
  and 
  another 
  character 
  which 
  seems 
  of 
  some 
  specific 
  value 
  is 
  the 
  nature 
  of 
  

   the 
  uppermost 
  section, 
  often 
  isolated, 
  of 
  the 
  series 
  of 
  combs 
  on 
  the 
  anterior 
  part 
  

   of 
  the 
  last 
  segment 
  ; 
  this 
  I 
  have 
  called 
  the 
  dorso-lateral 
  comb. 
  It 
  is 
  not 
  always 
  

   present 
  and 
  varies 
  much 
  in 
  form. 
  

  

  Specific 
  differences 
  amongst 
  the 
  larvae 
  are, 
  except 
  in 
  certain 
  species, 
  not 
  so 
  easy 
  

   to 
  detect, 
  especially 
  in 
  those 
  of 
  Haematopota. 
  They 
  are 
  generally 
  to 
  be 
  found 
  in 
  

   the 
  distribution 
  of 
  the 
  pigmented 
  areas 
  on 
  the 
  last 
  segment 
  around 
  the 
  base 
  of 
  the 
  

   syphon 
  and 
  the 
  anus. 
  These 
  so-called 
  pigmented 
  areas 
  are 
  really, 
  as 
  Mr. 
  Waterston 
  

   has 
  pointed 
  out 
  to 
  me, 
  areas 
  of 
  pigmented 
  hairs, 
  in 
  which 
  are 
  entangled 
  small 
  

   foreign 
  bodies. 
  Their 
  actual 
  colour 
  therefore 
  varies 
  to 
  some 
  extent 
  with 
  that 
  of 
  the 
  

   medium 
  in 
  which 
  the 
  larvae 
  have 
  lived. 
  The 
  amount 
  of 
  pigmentation, 
  though 
  not 
  

   its 
  distribution, 
  also 
  varies 
  with 
  the 
  age 
  of 
  the 
  larva. 
  

  

  Owing 
  to 
  the 
  absence 
  of 
  Mr. 
  E. 
  E. 
  Austen 
  on 
  active 
  service, 
  I 
  have 
  been 
  compelled 
  

   myself 
  to 
  describe 
  the 
  more 
  striking 
  of 
  the 
  new 
  species 
  in 
  the 
  collection 
  and 
  have 
  

   utilised 
  the 
  beautiful 
  drawings 
  of 
  Mr. 
  Terzi, 
  which 
  had 
  been 
  intended 
  for 
  a 
  separate 
  

   paper 
  by 
  him, 
  to 
  accompany 
  my 
  notes 
  on 
  the 
  insects 
  themselves 
  and 
  their 
  

   life- 
  histories. 
  I 
  also 
  received 
  most 
  valuable 
  assistance 
  in 
  Nyasaland 
  from 
  

   Mr. 
  E. 
  Ballard, 
  then 
  Government 
  Entomologist 
  in 
  that 
  Protectorate, 
  who 
  was 
  

   kind 
  enough 
  to 
  make 
  a 
  number 
  of 
  drawings 
  from 
  life 
  of 
  the 
  various 
  larvae 
  then 
  

   being 
  discovered, 
  which 
  were 
  subsequently 
  invaluable 
  in 
  the 
  difficult 
  work 
  of 
  

   identifying 
  and 
  sorting 
  them. 
  

  

  