con- 
these  acquired  them  through  what  Minchin*  has  termed  the 
taminative  ’  method. 
As  a  result  we  are  led  to  express  the  opinion  that  the  distribution 
of  Gl.  inorsitans  is  entirely  dependent  upon  the  nature  of  the  country 
and  its  flora,  the  association  with  the  fauna  is  largely  fortuitous,  and 
that  a  perpetual  supply  of  mammalian  blood  is  not  imperative  to  its 
at  least  temporary  existence. 
Relation  to  disease 
It  has  become  almost  an  axiom  that  Gl.  niorsitans  indicates 
trypanosomiasis ;  much  further  study  is  needed  to  decide  this  point. 
Wherever  disease  exists,  whether  positively  diagnosed  as  a  trypano¬ 
some  infection  or  not,  and  this  fly  can  be  caught  within  five  miles  or 
perhaps  more,  even  if  it  be  but  a  solitary  individual,  the  owner  will 
remain  convinced  of  its  causal  relationship.  There  are,  however, 
certain  instances  which  would  indicate  that  this  fly  may  exist  within  a 
short  distance  of  cattle  without  producing  any  noticeable  damage. 
In  a  previous  reportf  we  noted  an  example  on  the  River  Kafue, 
and  mentioned  two  villages  (Chinyama  and  Chiwala)  where  cattle 
are,  or  have  been  kept,  within  a  mile  of  permanently  infested  bush, 
and  which  unquestionably  at  some  time  have  been  bitten;  indeed 
morsitans  has  been  caught  by  a  European  feeding  on  these  animals 
In  North-Eastern  Rhodesia  we  were  informed  that  cattle  had  been 
for  some  time  grazed  in  the  Loangwa  Valley  at  a  place  where  we 
took  tsetse,  and  without  any  suspicion  of  infection  resulting  ;  and  at 
Mpika  and  Luena,  the  natural  haunts  of  the  fly  are  so  close  that  it 
is  difficult  to  consider  that  these  cattle  have  never  been  bitten.  The 
same  applies  to  the  native  cattle  at  Luchembe  with  Gl.  morsitans  all 
around,  and  to  the  Government-owned  stock  at  Kalungwisi  {Gl 
palpalts)  and  Chienji.  Still  more  striking  examples  are  afforded 
by  those  herds  which  until  recently  were  driven  from  German  East 
Africa  into  Southern  Rhodesia,  approximately  i,ooo  miles.  Of 
course,  every  precaution  was  taken  to  prevent  contact  with  Glossina, 
and  circuitous  routes  were  followed  to  avoid  them  ;  but  deaths  were 
♦  Minchin.  Proc.  Roy.  Soc.  Series  B.,  Vol.  79,  No.  528. 
t  Montgomery,  R.  E.,  and  Kinghorn,  A.  A  Report  on  Trypanosomiasis 
Stock  in  North-Western  Rhodesia.  Annals  Trop.  Med.  and  Parasitology,  9  >  ■  ’ 
