﻿440 
  W. 
  F. 
  FISKE. 
  

  

  lighter 
  than 
  conditions, 
  apart 
  from 
  the 
  very 
  exceptional 
  number 
  of 
  dragonnies, 
  

   would 
  have 
  led 
  one 
  to 
  expect. 
  It 
  seemed 
  quite 
  probable 
  that 
  the 
  destructor 
  was 
  

   responsible 
  for 
  a 
  considerably 
  less 
  heavy 
  infestation 
  than 
  would 
  otherwise 
  have 
  

   occurred. 
  

  

  There 
  is 
  this 
  difference 
  between 
  spider 
  and 
  dragonfly 
  — 
  that 
  sheltering 
  vegetation 
  

   is 
  of 
  little 
  or 
  no 
  protective 
  value 
  against 
  spiders, 
  but 
  of 
  much 
  protective 
  value 
  against 
  

   dragonnies. 
  They 
  will 
  not 
  follow 
  a 
  moving 
  animal 
  into 
  cover, 
  and 
  the 
  flies 
  are 
  not 
  

   likely 
  to 
  be 
  captured 
  unless 
  they 
  hunt 
  in 
  the 
  open. 
  

  

  Apart 
  from 
  spiders 
  and 
  dragonnies 
  no 
  destructive 
  enemies 
  of 
  tsetse 
  have 
  been 
  

   observed 
  that 
  appeared 
  to 
  be 
  specifically 
  responsible 
  for 
  appreciable 
  reduction 
  in 
  

   density 
  of 
  Glossina 
  palpalis. 
  

  

  (3). 
  Bembex. 
  

  

  A 
  wasp 
  of 
  the 
  genus 
  Bembex 
  works 
  somewhat 
  like 
  the 
  dragonfly 
  in 
  following 
  moving 
  

   animals 
  and 
  picking 
  off 
  flies 
  attracted 
  to 
  them. 
  Its 
  habits 
  have 
  been 
  described 
  by 
  

   Dr. 
  Carpenter. 
  • 
  Though 
  very 
  variable 
  in 
  density 
  it 
  is 
  nowhere 
  excessively 
  common, 
  

   and 
  at 
  most 
  points 
  was 
  not 
  observed 
  to 
  occur 
  at 
  all. 
  It 
  would 
  stand 
  third 
  in 
  

   importance 
  of 
  the 
  destructors 
  of 
  adult 
  flies 
  observed 
  at 
  work, 
  but 
  at 
  no 
  point 
  did 
  

   it 
  appear 
  to 
  produce 
  an 
  appreciable 
  effect 
  on 
  density 
  of 
  fly. 
  

  

  (4). 
  Miscellaneous 
  Destructors. 
  

  

  Small 
  lizards 
  are 
  among 
  the 
  most 
  numerous 
  of 
  entomophagous 
  creatures 
  which 
  

   hunt 
  in 
  the 
  haunts 
  of 
  tsetse, 
  and 
  it 
  has 
  seemed 
  probable 
  that 
  they 
  destroy 
  many 
  

   flies. 
  They 
  are 
  nearly 
  everywhere 
  common, 
  and 
  vary 
  relatively 
  little 
  in 
  local 
  density. 
  

  

  A 
  fair 
  number 
  of 
  other 
  entomophagids 
  have 
  been 
  observed 
  working 
  in 
  the 
  haunts 
  

   of 
  tsetse, 
  but 
  none 
  among 
  them 
  has 
  appeared 
  to 
  be 
  sufficiently 
  numerous 
  to 
  be 
  of 
  

   any 
  consequence 
  as 
  an 
  enemy. 
  

  

  It 
  is 
  to 
  be 
  noted, 
  however, 
  that 
  it 
  is 
  virtually 
  impossible 
  to 
  study 
  the 
  actual 
  or 
  

   potential 
  destructors 
  of 
  the 
  inactive 
  flies. 
  It 
  is 
  almost 
  impossible 
  to 
  discover 
  the 
  

   inactive 
  flies 
  without 
  putting 
  them 
  to 
  flight, 
  and 
  nothing 
  is 
  known 
  of 
  the 
  specific 
  

   dangers 
  that 
  beset 
  them. 
  

  

  IX 
  (c). 
  Parasitic 
  and 
  Predatory 
  Destruction 
  of 
  the 
  Larvae 
  and 
  Puparia. 
  

  

  (1). 
  Ants. 
  

  

  Almost 
  the 
  only 
  insects 
  common 
  at 
  breeding 
  grounds 
  in 
  clean-washed 
  deposits 
  

   of 
  beach 
  sand 
  and 
  gravel 
  are 
  the 
  ants 
  which 
  run 
  about 
  over 
  the 
  surface. 
  These 
  would 
  

   destroy 
  the 
  weak 
  larvae 
  of 
  tsetse 
  if 
  the 
  latter 
  did 
  not 
  bury 
  themselves 
  quickly 
  below 
  

   the 
  surface. 
  The 
  prescience 
  of 
  the 
  female 
  flies 
  guides 
  them 
  to 
  spots 
  where 
  their 
  

   young 
  are 
  not 
  unduly 
  exposed 
  to 
  this 
  danger. 
  

  

  There 
  are 
  numerous 
  species 
  of 
  ants 
  which 
  will 
  destroy 
  the 
  puparia 
  if 
  encountered, 
  

   but 
  none 
  of 
  these 
  are 
  known 
  or 
  suspected 
  to 
  burrow 
  beneath 
  the 
  surface 
  of 
  the 
  soil 
  in 
  

   breeding 
  grounds 
  in 
  search 
  of 
  buried 
  puparia. 
  The 
  " 
  red 
  driver 
  " 
  and 
  some 
  other 
  

   of 
  the 
  larger 
  ants 
  will 
  carry 
  the 
  puparia 
  away 
  bodily. 
  

  

  In 
  woodland, 
  or 
  where 
  there 
  is 
  a 
  thick 
  blanket 
  of 
  decaying 
  leaves 
  on 
  the 
  surface 
  

   of 
  the 
  soil, 
  there 
  are 
  species 
  of 
  ants 
  which 
  work 
  under 
  the 
  loosely 
  packed 
  material 
  

   and 
  which 
  will 
  destroy 
  any 
  Dipterous 
  puparia 
  encountered 
  in 
  it. 
  If 
  flies 
  ever 
  selected 
  

  

  