﻿424 
  W. 
  F. 
  FISKE. 
  

  

  At 
  point 
  15, 
  where 
  there 
  is 
  a 
  fine 
  " 
  fly 
  beach 
  " 
  with 
  full 
  southern 
  exposure, 
  the 
  

   trees 
  grow 
  so 
  luxuriantly 
  at 
  the 
  back 
  of 
  it 
  as 
  completely 
  to 
  shade 
  it 
  during 
  the 
  

   summer 
  months, 
  when 
  the 
  sun 
  is 
  in 
  the 
  north. 
  At 
  points 
  16 
  and 
  17 
  the 
  breeding 
  

   grounds 
  are 
  no 
  better, 
  but 
  the 
  sun 
  strikes 
  the 
  beach 
  and 
  the 
  flies 
  tend 
  to 
  concentrate 
  

   at 
  the 
  border 
  line 
  between 
  light 
  and 
  shade. 
  

  

  Similar 
  explanations 
  apply 
  at 
  other 
  points. 
  

  

  VII 
  (g). 
  Correlation 
  between 
  Density 
  of 
  Infestation 
  by 
  Glossina 
  pilpalis 
  and 
  

   Location 
  and 
  Extent 
  of 
  Breeding 
  Grounds 
  in 
  Beach 
  Sand 
  in 
  Regions 
  

   where 
  Food 
  and 
  Shelter 
  are 
  both 
  more 
  than 
  adequate. 
  

  

  Bugaba 
  was 
  the 
  first 
  of 
  the 
  larger 
  islands 
  selected 
  for 
  exhaustive 
  survey. 
  It 
  

   lies 
  near 
  the 
  centre 
  of 
  the 
  Bugalla-Bukassa 
  group, 
  and 
  in 
  its 
  general 
  aspects 
  

   resembles 
  those 
  surrounding 
  it. 
  

  

  Its 
  area 
  was 
  roughly 
  estimated 
  at 
  4,500 
  acres, 
  made 
  up 
  of 
  (a) 
  forest, 
  rather 
  more 
  

   than 
  one- 
  third 
  ; 
  (b) 
  open 
  grassland 
  (formerly 
  pasture), 
  about 
  one- 
  third 
  ; 
  (c) 
  jungle, 
  

   occupying 
  sites 
  of 
  abandoned 
  villages 
  and 
  plantations, 
  rather 
  less 
  than 
  one-third. 
  

  

  The 
  forest 
  fills 
  the 
  ravines, 
  covers 
  rocky 
  and 
  unarable 
  slopes 
  and 
  ridges, 
  and 
  forms 
  

   an 
  almost 
  continuous 
  belt 
  along 
  the 
  shore. 
  The 
  grass 
  land 
  lies 
  at 
  the 
  back 
  of 
  the 
  forest 
  

   belt 
  along 
  the 
  shore, 
  and 
  extends 
  up 
  the 
  slopes 
  to 
  the 
  borders 
  of 
  the 
  old 
  plantations. 
  

   The 
  villages 
  and 
  plantations 
  were 
  located 
  on 
  a 
  plateau 
  that 
  occupied 
  the 
  whole 
  

   central 
  portion 
  of 
  the 
  island. 
  None 
  were 
  seen 
  on 
  the 
  shore. 
  There 
  were 
  three 
  canoe 
  

   landings, 
  with 
  broad 
  foot-paths 
  leading 
  to 
  the 
  villages 
  and 
  plantations. 
  

  

  The 
  shore 
  line 
  was 
  estimated 
  at 
  between 
  16 
  and 
  17 
  miles. 
  It 
  was 
  sheltered 
  by 
  

   forest 
  for 
  almost 
  the 
  entire 
  distance. 
  The 
  southern 
  and 
  eastern 
  shores, 
  except 
  

   in 
  the 
  large 
  southern 
  bay, 
  were 
  generally 
  bold 
  and 
  rocky 
  — 
  at 
  points 
  precipitous. 
  

   Elsewhere 
  the 
  shore 
  was 
  for 
  the 
  most 
  part 
  marshy, 
  or 
  with 
  clay 
  banks, 
  but 
  with 
  

   rock 
  at 
  many 
  points. 
  In 
  the 
  aggregate 
  there 
  was 
  between 
  2 
  and 
  2J 
  miles 
  of 
  sandy 
  

   •or 
  gravelly 
  shore 
  which 
  might 
  be 
  accounted 
  as 
  potential 
  breeding 
  ground. 
  This 
  

   was 
  broken 
  into 
  numerous 
  short 
  reaches 
  of 
  from 
  20 
  to 
  100 
  yards 
  in 
  length, 
  distributed 
  

   irregularly 
  along 
  the 
  shore 
  line. 
  

  

  Infestation 
  by 
  Glossina 
  was 
  limited 
  to 
  a 
  narrow 
  belt 
  along 
  shore. 
  At 
  no 
  point 
  

   could 
  flies 
  be 
  detected 
  more 
  than 
  400 
  yards 
  inland, 
  and 
  at 
  only 
  one 
  point 
  could 
  

   any 
  be 
  found 
  more 
  than 
  200 
  yards 
  inland. 
  

  

  The 
  longshore 
  infestation 
  was 
  light. 
  The 
  maximum 
  male 
  density 
  at 
  any 
  of 
  the 
  

   48 
  observations 
  points 
  was 
  26-0. 
  The 
  average 
  for 
  all 
  points 
  was 
  6*7 
  — 
  far 
  below 
  

   the 
  average 
  for 
  the 
  lake 
  region 
  as 
  a 
  whole 
  of 
  approximately 
  12*5. 
  

  

  Food 
  was 
  plentiful. 
  Crocodiles, 
  Varanus 
  and 
  hippo 
  were 
  all 
  common 
  ; 
  situtunga 
  

   had 
  newly 
  immigrated 
  from 
  Sesse 
  (Bugalla) 
  Island, 
  and 
  a 
  few 
  tracks 
  were 
  seen 
  

   at 
  only 
  one 
  point. 
  The 
  female 
  percentage 
  was 
  very 
  low 
  : 
  7*9 
  for 
  the 
  total 
  catch 
  

   on 
  the 
  island. 
  

  

  The 
  coincidence 
  of 
  infestation 
  with 
  the 
  location 
  and 
  character 
  of 
  the 
  sandy 
  

   or 
  gravelly 
  reaches 
  that 
  offered 
  potential 
  breeding 
  ground 
  was 
  gratifyingly 
  precise. 
  

   At 
  or 
  adjacent 
  to 
  every 
  point 
  on 
  the 
  shore 
  where 
  sandy 
  or 
  gravelly 
  soil 
  was 
  exposed 
  

   to 
  the 
  surface 
  (i.e., 
  not 
  concealed 
  beneath 
  grass 
  or 
  leaf-mould) 
  and 
  properly 
  

   shaded, 
  the 
  local 
  density 
  of 
  fly 
  exceeded 
  the 
  average. 
  At 
  no 
  point 
  not 
  at 
  or 
  adj 
  acent 
  

  

  