319 
drafting  of  Government  stock  from  the  farms  to  district  officials,  or 
to  settlers  who  hire  cows  for  a  term  of  years.  Such  movements  will 
rarely  exceed  lOO  miles.  Transport  is  entirely  by  native  porters, 
the  few  donkeys  being  used  for  riding  in  the  district,  and  are  only 
exceptionally  taken  any  distance.  Most  of  them  have  come  originally 
from  German  East  Africa. 
Ill-  OCCURRENCE  OF  BITING  FLIES 
The  barrier  to  the  efficient  and  immediate  development  of  this 
virgin  country  is  unquestionably  the  wide  distribution  of  trypano¬ 
somiasis  and  the  transmitting  flies. 
I.  Glossina.  (a)  Glossina  falpalis  is  as  yet  only  known  from 
the  river  Luapula  to  the  North  of  12-^  South,  around  Lake  Tangan¬ 
yika  and  on  some  tributary  rivers.  It  has  not  been  incriminated  for 
stock  in  Rhodesia,  and  cattle  at  Kalung^visi  and  Chienji  are  grazed 
close  to  Its  ranges.  The  distribution  of  this  fly  is  given  more  in 
detail  elsewhere  (pp.  281-3). 
{F)  Glossina  morsitans  is  found  over  the  greater  part  of  the  terri¬ 
tory;  indeed,  if  the  district  of  Fort  Jameson,  the  Tanganyika-Nyasa 
plateau  and  the  neighbourhood  of  Serenji  were  excluded,  it  would 
be  difficult  to  assert  its  perpetual  absence  from  any  area  of  fifty- 
miles  square.  The  statement  made  by  Sir  Harry  Johnston*  that 
this  fly  is  not  found  in  Nyasaland  at  an  altitude  of  more  than  3,000 
feet  does  not  obtain  in  Rhodesia,  where  the  average  height  above  sea 
level  of  the  heavily  infested  Chinsali  and  Mpika  districts  is  more  than 
4,000  feet,  whilst  they  have  been  continually  taken  on  the  Machinga 
Hills  to  the  West  of  the  Loangwa,  which  approach  closely  to 
5,000  feet,  and  a  European  crossing  the  Nyasa-Loangwa  watershed 
East  of  Chinsali,  which  is  of  even  greater  altitude,  states  in  a  letter 
that  he  ‘  found  the  fly  numerous  right  on  the  watershed  on  both  sides 
of  the  border.’  They  are  equally  prevalent  in  the  Loangwa  valley 
(2-3,000  feet),  and  at  less  than  1,000  feet  on  the  Shire  river. 
We  were  unable  to  make  any  personal  observations  as  to  the 
effect  of  season  fer  se  on  the  distribution  of  this  fly ;  but  the  reports 
given  us  by  residents  indicate  a  lack  of  marked  variations.  The 
Johnston,  Sir  H.  H.,  British  Central  Africa,  London,  1897. 
