﻿84 
  RUPERT 
  W. 
  JACK. 
  

  

  feeding 
  on 
  animals 
  suffering 
  from 
  rinderpest 
  may 
  have 
  actually 
  killed 
  the 
  flies. 
  

   With 
  respect 
  to 
  the 
  latter, 
  observations 
  might 
  have 
  been 
  made 
  in 
  East 
  Africa 
  during 
  

   recent 
  years, 
  but 
  it 
  is 
  on 
  the 
  face 
  of 
  it 
  an 
  almost 
  incredible 
  hypothesis. 
  Moreover, 
  

   if 
  every 
  fly 
  was 
  killed 
  in 
  this 
  way 
  does 
  it 
  not 
  imply 
  a 
  very 
  close 
  association 
  between 
  

   animals 
  subject 
  to 
  rinderpest 
  and 
  tsetse-fly 
  ? 
  With 
  respect 
  to 
  the 
  climate 
  the 
  writer 
  

   has 
  been 
  at 
  some 
  pains 
  to 
  obtain 
  particulars 
  of 
  rainfall 
  and 
  temperature 
  in 
  Southern 
  

   Rhodesia 
  at 
  the 
  period 
  involved 
  and 
  there 
  is 
  nothing 
  whatever 
  to 
  suggest 
  any 
  remark- 
  

   able 
  deviation 
  from 
  the 
  normal. 
  The 
  following 
  returns 
  were 
  furnished 
  through 
  the 
  

   courtesy 
  of 
  the 
  Rev. 
  E. 
  Goetz, 
  S. 
  J., 
  M.A., 
  F.R.A.S., 
  of 
  Bulawayo. 
  

  

  A 
  set 
  of 
  observations 
  is 
  on 
  record 
  from 
  the 
  Zambesi 
  from 
  1891 
  to 
  1897, 
  but 
  some 
  

   of 
  these 
  were 
  taken 
  at 
  Baroma 
  and 
  some 
  at 
  Zumbo, 
  a 
  complete 
  set 
  for 
  either 
  station 
  

   being 
  lacking. 
  These 
  two 
  stations 
  are, 
  however, 
  only 
  about 
  fifty 
  miles 
  apart 
  and 
  the 
  

   climates 
  are 
  more 
  or 
  less 
  similar. 
  It 
  may 
  be 
  mentioned 
  that 
  fly 
  apparently 
  

   disappeared 
  from 
  this 
  vicinity 
  in 
  the 
  1896-7 
  season 
  and 
  has 
  not 
  since 
  reappeared. 
  

   The 
  records 
  for 
  three 
  seasons 
  ending 
  1896-7 
  are 
  given 
  on 
  the 
  opposite 
  page. 
  

  

  If 
  climatic 
  conditions 
  are 
  to 
  account 
  for 
  the 
  widespread 
  dying 
  out 
  of 
  tsetse-fly 
  at 
  

   this 
  period, 
  one 
  would 
  expect 
  either 
  an 
  intense 
  general 
  drought, 
  an 
  excessively 
  pro- 
  

   longed 
  period 
  of 
  dull 
  weather 
  and 
  rain, 
  an 
  excessively 
  high 
  maximum 
  or 
  an 
  excessively 
  

   low 
  minimum 
  temperature, 
  but 
  there 
  is 
  no 
  record 
  of 
  any 
  such 
  occurrence. 
  As 
  a 
  matter 
  

   of 
  fact 
  the 
  seasons 
  of 
  1889-90 
  and 
  1890-1 
  showed 
  far 
  heavier 
  rainfall, 
  as 
  also 
  did 
  last 
  

   season, 
  1917-18. 
  Dull 
  weather 
  was 
  so 
  prolonged 
  last 
  season 
  that 
  the 
  maize 
  crop 
  

   was 
  largely 
  a 
  failure 
  and 
  no 
  effect 
  is 
  apparent 
  on 
  the 
  tsetse-fly. 
  Seasons 
  of 
  much 
  

   lower 
  rainfall 
  than 
  1896-7 
  had 
  also 
  no 
  effect 
  on 
  the 
  pest, 
  and, 
  as 
  may 
  be 
  seen 
  from 
  the 
  

   record, 
  the 
  maximum 
  and 
  minimum 
  temperatures 
  recorded 
  did 
  not 
  actually 
  vary 
  

   as 
  widely 
  as 
  those 
  of 
  the 
  preceding 
  years. 
  

  

  These 
  figures 
  would 
  seem 
  to 
  dispose 
  effectively 
  of 
  the 
  theory 
  concerning 
  exceptional 
  

   meteorological 
  conditions, 
  and 
  at 
  present 
  we 
  are 
  altogether 
  without 
  any 
  plausible 
  

   explanation 
  to 
  account 
  for 
  the 
  immense 
  reduction 
  of 
  fly 
  at 
  that 
  period 
  except 
  the 
  

   slightly 
  antecedent 
  immense 
  reduction 
  of 
  wild 
  ungulates. 
  

  

  (3) 
  The 
  presence 
  of 
  nucleated 
  corpuscles 
  in 
  the 
  stomach 
  of 
  G. 
  morsitans 
  has 
  

   been 
  recorded 
  by 
  several 
  investigators, 
  but 
  there 
  is 
  apparently 
  only 
  one 
  record 
  of 
  

   any 
  considerable 
  percentage 
  of 
  flies 
  showing 
  this 
  evidence 
  of 
  a 
  non-mammalian 
  

   diet,* 
  and 
  the 
  circumstances 
  may 
  have 
  been 
  exceptional. 
  There 
  is 
  no 
  doubt 
  that 
  a 
  

   hungry 
  morsitans 
  is 
  quite 
  willing 
  to 
  feed 
  upon 
  any 
  warm-blooded 
  creature, 
  and 
  

   possibly 
  any 
  vertebrate, 
  that 
  comes 
  within 
  its 
  notice, 
  and 
  in 
  the 
  case 
  of 
  certain 
  large 
  

   birds, 
  the 
  operation 
  should 
  not 
  be 
  difficult. 
  Amongst 
  those 
  which 
  no 
  doubt 
  con- 
  

   tribute 
  an 
  occasional 
  meal 
  to 
  the 
  fly 
  may 
  be 
  included 
  the 
  ostrich, 
  cranes, 
  herons, 
  

   ground 
  hornbills, 
  vultures 
  and 
  various 
  birds 
  of 
  prey, 
  including 
  eagles, 
  owls, 
  etc., 
  

   and 
  doubtless 
  several 
  other 
  types. 
  Such 
  birds 
  are 
  obviously 
  far 
  too 
  scarce 
  or 
  come 
  

   far 
  too 
  rarely 
  within 
  range 
  of 
  the 
  fly, 
  to 
  constitute 
  an 
  efficient 
  substitute 
  for 
  the 
  usual 
  

   mammalian 
  diet. 
  That 
  the 
  vast 
  majority 
  of 
  birds 
  with 
  their 
  active 
  dis- 
  

   positions 
  and 
  untiring 
  pertinacity 
  in 
  pecking 
  at 
  insects 
  serve 
  to 
  support 
  morsitans 
  

   is 
  extremely 
  unlikely, 
  and 
  there 
  appears 
  to 
  be 
  no 
  evidence 
  at 
  all 
  to 
  suggest 
  such 
  a 
  

   possibility. 
  

  

  * 
  [Lloyd, 
  Bull. 
  Ent. 
  Kes. 
  iii, 
  p. 
  236. 
  — 
  Of 
  52 
  flies 
  containing 
  blood, 
  the 
  nature 
  of 
  the 
  

   blood 
  cells 
  could 
  be 
  recognised 
  in 
  only 
  20; 
  of 
  these, 
  5 
  contained 
  no 
  n- 
  mammalian 
  

   nucleated 
  cells. 
  — 
  Ed.] 
  

  

  