264 
The  possibility  of  tsetse  flies  feeding  on  anything  except  blood 
has  recently  been  mooted  againd^  The  following  observation 
though  negative,  may  be  worth  noting. 
On  one  occasion  at  the  mouth  of  the  Kalambo  river,  a  tributary 
of  Lake  Tanganyika,  numbers  of  Gl.  falpalis  were  seen  to  settle  at 
the  edges  of  little  puddles  of  stagnant  water  containing  various  low 
forms  of  plant  life.  We  could  not  determine  that  they  were  sucking 
up  the  water,  and  at  the  time  were  not  in  a  position  to  examine  the 
flies. 
Nine  of  the  113  Gl.  morsitans  were  found  to  be  infected  with 
protozoa,  i.e.,  yS  per  cent.  This  intestinal  infection  apparently  tends 
to  die  out,  or  at  all  events,  the  parasites  do  not  retain  the 
ordinary  trypanosome  form  after  a  few  days,  as  is  evidenced  by  the 
following :  — 
Time  of  examination 
No.  Examined 
Male 
Female 
Percentage 
Freshly  caught 
41  fi;  positive) 
2  (negative) 
i5'i 
24  hours  after  capture 
6°  (4  n  ) 
6 
6 
48  T)  )1  )) 
2  (negative) 
0 
0 
9^  j)  11  11 
>, 
0 
0 
V.  INCIDENCE  OF  INFECTION  IN  PROBOSCIS 
As  stated  above,  infection  of  the  proboscis  of  Gl.  palpalis 
parasites  was  never  observed.  It  was  found  to  be  present  in  seven 
out  of  thirty-one  Gl.  morsitans,  2r2  per  cent.  In  contradistinction 
to  the  intestinal  infection,  that  of  the  proboscis  apparently  increases  in 
frequency  on  keeping  the  flies,  e.g. :  — 
Time  of  examination 
No.  examined 
No.  infected 
Percentage 
Freshly  caught 
8 
I 
12*4 
24  hours  after  capture 
10 
4 
40 
4®  11  1)  1) 
3 
2 
66-6 
96  „  „  „ 
12 
0 
0 
Condition  of  intestine  in 
infected  cases 
Parasites  present 
Parasites  present  in  3,  absent 
in  I 
Parasites  present  in  1,  ? 
other,  fly  lost 
