﻿52 
  

  

  LL. 
  LLOYD 
  — 
  FURTHER 
  NOTES 
  ON 
  THE 
  BIONOMICS 
  OF 
  

  

  In 
  the 
  series 
  fed 
  on 
  goats, 
  fowls 
  and 
  ducks 
  there 
  was 
  little 
  difference 
  in 
  the 
  average 
  

   life 
  of 
  the 
  flies. 
  The 
  best 
  results 
  in 
  this 
  respect 
  were 
  given 
  by 
  the 
  two 
  series 
  (Nos. 
  15 
  

   and 
  16) 
  on 
  ducks 
  and 
  one 
  series 
  (No. 
  3) 
  on 
  goats. 
  The 
  flies 
  fed 
  upon 
  monkeys 
  died 
  

   much 
  more 
  rapidly, 
  though 
  they 
  feed 
  readily 
  on 
  these 
  animals, 
  often 
  doing 
  so 
  when 
  

   they 
  will 
  not 
  take 
  food 
  from 
  a 
  goat. 
  The 
  low 
  temperatures 
  did 
  not 
  appear 
  to 
  affect 
  

   the 
  length 
  of 
  life 
  of 
  the 
  flies, 
  though 
  in 
  the 
  coldest 
  weather 
  they 
  were 
  very 
  sluggish 
  

   and 
  would 
  not 
  feed 
  until 
  they 
  had 
  been 
  warmed 
  by 
  the 
  sun. 
  

  

  A 
  comparison 
  of 
  the 
  numbers 
  of 
  pupae 
  produced, 
  making 
  due 
  allowance 
  for 
  the 
  

   temperature, 
  shows 
  that 
  mammalian 
  blood 
  has 
  no 
  definite 
  advantage 
  over 
  avian 
  in 
  

   this 
  respect. 
  Those 
  fed 
  upon 
  goats 
  bred 
  a 
  little 
  more 
  freely 
  than 
  those 
  fed 
  upon 
  fowls 
  

   and 
  ducks 
  ; 
  while 
  those 
  fed 
  upon 
  monkeys 
  were 
  less 
  prolific. 
  On 
  the 
  average 
  the 
  

   pupae 
  produced 
  on 
  mammalian 
  blood 
  are 
  larger 
  than 
  those 
  bred 
  on 
  avian 
  blood. 
  

   This 
  advantage 
  is 
  four 
  per 
  cent, 
  in 
  length 
  and 
  five 
  per 
  cent, 
  in 
  breadth 
  (Table 
  IV). 
  

   The 
  difference 
  is 
  obvious 
  in 
  the 
  flies 
  which 
  emerge 
  from 
  the 
  bred 
  pupae. 
  In 
  Table 
  IV 
  

   the 
  dimensions 
  of 
  50 
  pupae 
  collected 
  in 
  nature 
  are 
  included 
  for 
  comparison. 
  

  

  Table 
  IV. 
  

  

  A 
  Comparison 
  of 
  the 
  Dimensions 
  of 
  Pupae 
  bred 
  on 
  Mammalian 
  and 
  Avian 
  Blood. 
  

  

  Source 
  of 
  Pupae. 
  

  

  Number. 
  

  

  Average 
  length. 
  

  

  Average 
  breadth. 
  

  

  Collected 
  in 
  nature 
  . 
  . 
  

  

  50 
  

  

  601 
  mm. 
  

  

  3-40 
  mm. 
  

  

  Bred 
  on 
  goats 
  . 
  . 
  

  

  68 
  

  

  576 
  „ 
  

  

  318 
  „ 
  

  

  ,, 
  ,, 
  monkeys 
  

  

  18 
  

  

  5-66 
  „ 
  

  

  3-17 
  „ 
  

  

  Total 
  bred 
  on 
  mammals 
  

  

  86 
  

  

  574 
  „ 
  

  

  3-18 
  „ 
  

  

  Bred 
  on 
  fowls 
  . 
  . 
  

  

  45 
  

  

  5-50 
  „ 
  

  

  303 
  „ 
  

  

  ,, 
  „ 
  ducks 
  

  

  16 
  

  

  5-59 
  „ 
  

  

  305 
  „ 
  

  

  Total 
  bred 
  on 
  birds 
  . 
  . 
  

  

  61 
  

  

  5-52 
  „ 
  

  

  304 
  „ 
  

  

  In 
  the 
  avian 
  series 
  there 
  was 
  a 
  large 
  proportion 
  of 
  very 
  small 
  pupae. 
  Of 
  these 
  22 
  

   (36 
  per 
  cent.) 
  measured 
  5 
  5 
  mm. 
  or 
  less 
  in 
  length, 
  while 
  in 
  the 
  mammalian 
  series 
  11 
  

   (13 
  per 
  cent.) 
  only 
  were 
  of 
  these 
  dimensions. 
  The 
  avian 
  series 
  however 
  also 
  included 
  

   a 
  few 
  pupae 
  which 
  were 
  equal 
  in 
  size 
  to 
  the 
  largest 
  bred 
  on 
  mammals' 
  blood. 
  

  

  The 
  small 
  size 
  of 
  these 
  pupae 
  is 
  considered 
  to 
  be 
  due 
  to 
  the 
  pressure 
  of 
  the 
  clots 
  of 
  

   blood 
  which 
  form 
  in 
  the 
  sucking 
  stomachs 
  of 
  some 
  of 
  the 
  flies 
  when 
  fed 
  on 
  avian 
  

   blood.* 
  A 
  fly 
  containing 
  such 
  a 
  clot 
  has 
  the 
  appearance 
  of 
  being 
  newly 
  and 
  fully 
  

   fed. 
  Their 
  formation 
  appears 
  to 
  be 
  due 
  to 
  an 
  individual 
  peculiarity 
  of 
  some 
  of 
  the 
  

   flies. 
  The 
  following 
  experiment 
  shows 
  the 
  permanence 
  of 
  the 
  clots 
  when 
  once 
  formed. 
  

   A 
  cage 
  of 
  100 
  tsetse 
  were 
  fed 
  for 
  20 
  days 
  on 
  fowls 
  and 
  then 
  starved 
  for 
  ten 
  days. 
  At 
  

   the 
  end 
  of 
  this 
  period 
  75 
  of 
  the 
  flies 
  were 
  dead. 
  They 
  were 
  then 
  examined 
  and 
  of 
  the 
  

   total 
  62 
  were 
  found 
  to 
  have 
  clots 
  in 
  the 
  sucking 
  stomachs, 
  while 
  the 
  remaining 
  38 
  

   were 
  thin. 
  Among 
  the 
  25 
  living 
  flies 
  12 
  contained 
  clots. 
  Fifty 
  flies 
  which 
  had 
  been 
  

   fed 
  on 
  monkeys' 
  blood 
  for 
  50 
  days 
  were 
  similarly 
  starved 
  for 
  ten 
  days. 
  Only 
  one 
  of 
  

   the 
  flies 
  remained 
  alive 
  and 
  examination 
  showed 
  that 
  all 
  of 
  them 
  were 
  thin 
  and 
  con- 
  

   tained 
  only 
  blood 
  detritus. 
  

  

  * 
  Ann. 
  Trop. 
  Med. 
  and 
  Parasitology, 
  vii, 
  no. 
  2, 
  p. 
  285. 
  

  

  