﻿304 
  L. 
  H. 
  DUNN. 
  

  

  A 
  total 
  of 
  42 
  pairs 
  of 
  flies 
  were 
  observed, 
  and 
  the 
  results 
  obtained 
  are 
  shown 
  in 
  

   the 
  following 
  table 
  : 
  — 
  

  

  Females 
  Nos. 
  3 
  and 
  30 
  were 
  killed 
  on 
  the 
  thirty-fourth 
  day. 
  This 
  was 
  due 
  to 
  the 
  

   writer 
  leaving 
  for 
  the 
  United 
  States 
  on 
  the 
  day 
  following. 
  

  

  The 
  168 
  eggs 
  (f) 
  deposited 
  by 
  female 
  No. 
  21 
  on 
  the 
  fourth 
  day 
  consisted 
  of 
  two 
  

   batches, 
  95 
  in 
  the 
  a.m. 
  and 
  73 
  in 
  the 
  p.m. 
  

  

  Only 
  two 
  batches 
  of 
  eggs 
  of 
  the 
  entire 
  number 
  deposited 
  were 
  found 
  to 
  be 
  non-viable. 
  

   These 
  were 
  undoubtedly 
  infertile 
  eggs, 
  and 
  not 
  some 
  that 
  had 
  passed 
  through 
  the 
  

   autoclave 
  and 
  not 
  discovered 
  in 
  the 
  manure 
  before 
  being 
  placed 
  in 
  the 
  jar, 
  as 
  they 
  

   were 
  white 
  and 
  of 
  normal 
  size, 
  while 
  the 
  three 
  batches 
  of 
  eggs 
  previously 
  mentioned 
  

   as 
  being 
  autoclaved 
  were 
  noticed 
  to 
  be 
  apparently 
  enlarged 
  and 
  with 
  a 
  yeUowish 
  

   tinge, 
  which 
  was 
  possibly 
  caused 
  by 
  taking 
  up 
  some 
  colour 
  from 
  the 
  steaming 
  manure. 
  

   Moreover, 
  these 
  two 
  batches 
  were 
  deposited 
  by 
  the 
  same 
  female 
  on 
  two 
  successive 
  days. 
  

   These 
  two 
  batches 
  are 
  not 
  included 
  in 
  the 
  tables 
  on 
  oviposition 
  or 
  in 
  the 
  general 
  

   count. 
  

  

  As 
  previously 
  mentioned, 
  the 
  flies 
  used 
  for 
  these 
  observations 
  were 
  bred 
  from 
  three 
  

   different 
  strains, 
  but 
  no 
  appreciable 
  difference 
  was 
  noted 
  in 
  any 
  way. 
  

  

  The 
  results 
  obtained 
  by 
  Pomeroy 
  while 
  working 
  with 
  isolated 
  pairs, 
  as 
  given 
  by 
  

   Hutchison, 
  differed 
  greatly 
  from 
  those 
  of 
  the 
  series 
  carried 
  out 
  by 
  myself. 
  He 
  

   succeeded 
  in 
  getting 
  but 
  7 
  females 
  out 
  of 
  30 
  to 
  oviposit 
  while 
  confined 
  as 
  isolated 
  pairs, 
  

   and 
  but 
  2 
  of 
  the 
  7 
  deposited 
  a 
  second 
  batch 
  of 
  eggs. 
  The 
  maximum 
  number 
  of 
  eggs 
  

   deposited 
  by 
  any 
  one 
  female 
  out 
  of 
  the 
  7 
  that 
  oviposited 
  was 
  110. 
  In 
  writing 
  of 
  

   Pomeroy's 
  observations, 
  Hutchison* 
  states, 
  " 
  The 
  fact 
  that 
  only 
  7 
  out 
  of 
  some 
  30 
  

   tests 
  gave 
  any 
  positive 
  results 
  points 
  to 
  the 
  difficulties 
  in 
  obtaining 
  significant 
  data 
  

   from 
  experiments 
  performed 
  under 
  artificial 
  conditions." 
  

  

  Judging 
  from 
  the 
  literature 
  at 
  hand, 
  it 
  is 
  quite 
  probable 
  that 
  the 
  observations 
  on 
  

   the 
  oviposition 
  of 
  M. 
  domestica 
  as 
  shown 
  in 
  the 
  foregoing 
  pages 
  are 
  the 
  most 
  successful 
  

   and 
  accurate 
  that 
  have 
  as 
  yet 
  been 
  made. 
  More 
  especially 
  is 
  this 
  evident 
  owing 
  to 
  

   the 
  observations 
  having 
  been 
  made 
  while 
  working 
  with 
  isolated 
  pairs 
  of 
  flies, 
  which 
  

   in 
  my 
  estimation 
  is 
  the 
  only 
  satisfactory 
  method 
  of 
  obtaining 
  accurate 
  results 
  in 
  

   oviposition 
  studies. 
  

  

  These 
  observations 
  also 
  show 
  that 
  the 
  time 
  between 
  deposits 
  of 
  eggs 
  may 
  be 
  much 
  

   shorter 
  than 
  has 
  been 
  heretofore 
  recognised. 
  This 
  was 
  indicated 
  by 
  a 
  number 
  of 
  

   females 
  depositing 
  large 
  batches 
  of 
  eggs 
  at 
  intervals 
  of 
  approximately 
  36 
  hours. 
  

  

  Although 
  no 
  special 
  attempts 
  were 
  made 
  to 
  ascertain 
  the 
  pre-copulation 
  period 
  

   of 
  each 
  pair, 
  it 
  was 
  noted 
  in 
  several 
  instances, 
  in 
  two 
  of 
  which 
  copulation 
  occurred 
  

   within 
  24 
  hours 
  after 
  emergence. 
  Promptness 
  in 
  supplying 
  food 
  and 
  material 
  in 
  which 
  

   to 
  deposit 
  eggs 
  after 
  the 
  adults 
  emerge 
  seems 
  to 
  exert 
  considerable 
  influence 
  on 
  the 
  

   length 
  of 
  this 
  period. 
  

  

  It 
  was 
  noted 
  that 
  after 
  successful 
  copulation 
  once 
  occurred 
  the 
  female 
  remained 
  

   fertilised 
  throughout 
  her 
  life-period, 
  and 
  all 
  eggs 
  deposited 
  were 
  fertile, 
  with 
  but 
  

   very 
  few 
  exceptions, 
  without 
  later 
  copulation 
  being 
  necessary. 
  

  

  Temperature 
  and 
  humidity 
  are 
  factors 
  that 
  undoubtedly 
  have 
  a 
  strong 
  influence 
  

   on 
  the 
  life-history 
  of 
  the 
  house-fly, 
  and 
  it 
  may 
  be 
  safely 
  assumed 
  that 
  the 
  biology 
  of 
  

   this 
  fly 
  in 
  the 
  tropics 
  differs 
  somewhat 
  from 
  that 
  in 
  temperate 
  regions. 
  However, 
  the 
  

   dry 
  season 
  in 
  Panama, 
  during 
  which 
  time 
  these 
  observations 
  were 
  carried 
  out, 
  is 
  not 
  

   so 
  different 
  from 
  the 
  summer 
  months 
  in 
  the 
  southern 
  part 
  of 
  the 
  United 
  States 
  as 
  

   one 
  would 
  expect. 
  

  

  * 
  Hutchison, 
  R. 
  H. 
  " 
  Notes 
  on 
  the 
  Pre-oviposition 
  Period 
  of 
  the 
  House-fly, 
  Musca 
  

   domestica, 
  L." 
  U.S. 
  Dept. 
  Agric, 
  Bull. 
  345, 
  Feb. 
  1916, 
  p. 
  8. 
  

  

  