﻿INVESTIGATIONS 
  INTO 
  THE 
  BIONOMICS 
  OP 
  GLOSSINA 
  PALPALIS. 
  

  

  459 
  

  

  Conditions 
  in 
  1906. 
  

   (Report 
  of 
  Dr. 
  R. 
  Van 
  Someren.) 
  

  

  "While 
  on 
  one 
  side 
  of 
  the 
  point 
  we 
  

   caught 
  8 
  on 
  the 
  two 
  occasions 
  we 
  waited 
  

   for 
  them, 
  on 
  the 
  rocks 
  on 
  the 
  other 
  side 
  

   some 
  10 
  yards 
  [rods 
  ?] 
  across, 
  where 
  

   several 
  men 
  and 
  boys 
  were 
  sitting 
  fishing, 
  

   we 
  did 
  not 
  observe 
  a 
  single 
  fly 
  about 
  their 
  

   persons, 
  and 
  amongst 
  a 
  group 
  of 
  some 
  20 
  

   drawing 
  a 
  seine 
  a 
  little 
  further 
  along 
  we 
  

   caught 
  only 
  one 
  the 
  second 
  day. 
  

  

  " 
  The 
  physical 
  conditions 
  in 
  these 
  sec- 
  

   tions, 
  starting 
  from 
  our 
  limit 
  in 
  the 
  

   Gwamba 
  southwards, 
  are 
  as 
  follows 
  : 
  — 
  

  

  " 
  A 
  sandy 
  beach 
  extends 
  practically 
  the 
  

   whole 
  way, 
  except 
  close 
  to 
  Sekwe, 
  where 
  

   the 
  trees 
  are 
  practically 
  at 
  the 
  water's 
  edge. 
  

  

  " 
  The 
  land 
  behind 
  is 
  low 
  and 
  covered 
  

   in 
  parts 
  with 
  scrub 
  ; 
  in 
  others 
  with 
  

   larger 
  trees 
  with 
  here 
  and 
  there 
  wide 
  

   open 
  areas 
  intervening 
  again. 
  At 
  some 
  

   portions 
  the 
  tree-covered 
  areas 
  are 
  swampy 
  

   some 
  distance 
  back 
  from 
  the 
  beach. 
  

  

  " 
  At 
  the 
  fly 
  limit 
  north 
  of 
  Namirembe 
  

   this 
  swampy 
  part 
  comes 
  quite 
  close 
  to 
  

   the 
  beach 
  and 
  remains 
  so 
  more 
  or 
  less 
  

   continuously 
  till 
  close 
  to 
  Bale, 
  and 
  con- 
  

   tinues 
  thus 
  practically 
  to 
  Sekwe, 
  except 
  

   for 
  portions 
  here 
  and 
  there 
  where 
  the 
  

   swamp 
  line 
  again 
  comes 
  close 
  to 
  the 
  

   beach. 
  In 
  many 
  parts 
  the 
  beach 
  is 
  not 
  

   so 
  high 
  that 
  during 
  high 
  winds 
  the 
  waves 
  

   wash 
  right 
  over 
  into 
  the 
  swamp. 
  

  

  Conditions 
  in 
  1915. 
  

  

  (Fly 
  Survey.) 
  

  

  The 
  density 
  at 
  these 
  points 
  (Sekwe) 
  

   averaged 
  9*2 
  in 
  1915 
  — 
  probably 
  not 
  far 
  

   different 
  from 
  that 
  observed 
  by 
  Dr. 
  Van 
  

   Someren 
  in 
  1906, 
  except 
  that 
  it 
  applies 
  

   to 
  the 
  shore 
  in 
  both 
  directions 
  from 
  the 
  

   rocks. 
  (These 
  are 
  the 
  only 
  rocks 
  for 
  

   miles 
  in 
  either 
  direction 
  and 
  identify 
  the 
  

   locality 
  absolutely.) 
  

  

  The 
  physical 
  conditions 
  in 
  these 
  sections 
  

   have 
  undergone 
  radical 
  changes 
  owing 
  to 
  

   the 
  falling 
  of 
  the 
  level 
  of 
  the 
  lake. 
  

  

  A 
  sandy 
  beach 
  is 
  practically 
  continuous 
  

   the 
  whole 
  way 
  except 
  for 
  the 
  reach 
  of 
  two 
  

   miles 
  north 
  of 
  Sekwe. 
  Here 
  the 
  beach 
  

   of 
  1906 
  is 
  separated 
  from 
  the 
  present 
  shore 
  

   line 
  by 
  a 
  belt 
  of 
  marsh, 
  very 
  soft 
  and 
  

   muddy, 
  into 
  which 
  one 
  sinks 
  knee 
  to 
  thigh 
  

   deep. 
  Outside 
  the 
  marsh 
  are 
  the 
  beginnings 
  

   of 
  a 
  new 
  beach, 
  very 
  narrow 
  and 
  wet. 
  

   Outside 
  of 
  this 
  is 
  a 
  hedge 
  of 
  ambatch, 
  or 
  

   merinde, 
  that 
  only 
  permits 
  passage 
  of 
  

   canoes 
  inward 
  to 
  the 
  land 
  at 
  a 
  few 
  points. 
  

   The 
  old 
  beach 
  of 
  1906, 
  thus 
  completely 
  

   cut 
  off 
  from 
  the 
  present 
  waterline, 
  is 
  over- 
  

   grown 
  with 
  an 
  excessively 
  dense 
  tangle 
  

   of 
  vegetation. 
  This 
  continues 
  to 
  a 
  point 
  

   "close 
  to 
  Sekwe" 
  where 
  the 
  trees 
  are 
  still 
  

   "practically 
  at 
  the 
  water's 
  edge," 
  and 
  

   (the 
  shore 
  being 
  rocky 
  or 
  falling 
  away 
  

   steeply) 
  the 
  conditions 
  are 
  virtually 
  un- 
  

   changed, 
  either 
  physically 
  or, 
  as 
  nearly 
  

   as 
  can 
  be 
  judged, 
  with 
  respect 
  to 
  infestation 
  

   by 
  fly. 
  

  

  These 
  conditions 
  are 
  unchanged 
  ; 
  there 
  

   is 
  more 
  of 
  swampy 
  land 
  back 
  from 
  beach 
  

   than 
  Dr. 
  Van 
  Someren's 
  notes 
  might 
  imply. 
  

  

  The 
  falling 
  water 
  wrought 
  most 
  radical 
  

   changes 
  in 
  the 
  conditions 
  here 
  described. 
  

   The 
  beach 
  of 
  1906 
  is 
  now 
  high 
  and 
  dry, 
  

   and 
  there 
  may 
  be 
  20, 
  30, 
  50 
  or 
  in 
  some 
  

   places 
  100 
  yards 
  of 
  dry 
  sandy 
  embank- 
  

   ment 
  between 
  the 
  present 
  beach 
  line 
  and 
  

   the 
  tree 
  or 
  reed 
  grown 
  swamps 
  and 
  marshes 
  

   back 
  of 
  it. 
  This 
  almost 
  continuous 
  em- 
  

   bankment 
  is 
  partly 
  open 
  in 
  places, 
  and 
  in 
  

   other 
  places 
  overgrown 
  with 
  dense 
  jungle. 
  

   Instead 
  of 
  a 
  narrow 
  wet 
  beach 
  with 
  high 
  

   waves 
  breaking 
  over 
  it, 
  we 
  have 
  a 
  broad 
  

   sandy 
  embankment 
  with 
  swampy 
  areas 
  

   " 
  some 
  distance 
  back 
  from 
  the 
  beach," 
  

   and 
  providing 
  ideal 
  shelter 
  and 
  breeding 
  

   ground 
  for 
  the 
  fly. 
  It 
  should 
  be 
  added 
  

   that 
  in 
  1915 
  somewhat 
  higher 
  water 
  than 
  

   for 
  the 
  past 
  few 
  years 
  was 
  working 
  still 
  

   further 
  changes 
  ; 
  building 
  new 
  beaches 
  and 
  

   cutting 
  off 
  new 
  bits 
  of 
  newly 
  made 
  marsh 
  

   from 
  the 
  open 
  lake 
  at 
  certain 
  points, 
  and 
  

  

  (050) 
  

  

  