202 
the  thorax,  and  traction  was  made  on  the  everted  hypopygium  in  the 
male,  or  on  the  last  abdominal  segment  of  the  female,  with  a  second 
needle.  The  last  segment  was  thus  separated  from  the  rest  of  the 
abdomen  and  with  it  the  attached  gut  was  pulled  out  into  the  drop 
of  fluid.  With  a  little  care  the  whole  intestine,  including  the 
oesophageal  portion,  could  be  obtained  intact  and  quite  free  from  the 
other  abdominal  contents.  The  malpighian  tubules  were  usually 
the  only  other  organs  which  came  away  with  the  gut ;  sometimes 
spermathecae,  ovaries,  and  uterus.  This  procedure,  as  will  be  seen, 
varies  slightly  from  that  given  by  Minchin,^  in  which  the  terminal 
segment  of  the  fly  was  snipped  off  and  the  whole  of  the  abdominal 
viscera  expressed. 
The  whole  intestine  was  mounted  in  the  salt-citrate  solution  and 
examined  under  the  low  and  high  powers.  Fresh  preparations  and 
smears  were  afterwards  made  from  the  various  portions  of  the 
intestine  and  other  abdominal  contents.  The  smears  were  fixed  in 
absolute  alcohol  and  Fleming’s  solution  and  stained  by  Giemsa’s  and 
Leishman’s  methods. 
The  proboscis  was  examined  in  salt-citrate  solution,  and  smears 
were  made  and  stained  as  in  the  case  of  the  intestinal  contents. 
IV.  INCIDENCE  OF  INTESTINAL  CONTAMINATION 
A.  Glossina  falfalis. 
During  July,  1,409  Gl.  palpalis  were  caught,  1,282  males  and  127 
females.  Of  these,  185  were  dissected  and  examined,  and  78  were 
found  to  harbour  intestinal  protozoa,  a  percentage  of  42T.  This 
IS  by  far  the  highest  percentage  of  tsetse  flies  which  has  yet  been 
recorded  as  containing  these  trypanosomes.  In  the  Sesse  Islands 
II  per  cent,  were  infected, -m  the  French  Congo  about  10  per  cent, 
in  the  Congo  F ree  State  infection  is  apparently  unknown,  according  to 
Dutton,  Todd  and  Hanington.*i° 
The  comparative  ratio  of  infection  in  the  two  sexes  was 
approximately  the  same. 
Positive 
Negative 
Percentage 
Males  ... 
73 
96 
43-1 
Females 
5 
II 
37-5 
*  This  is  rather  questionable,  however,  judging  from  the  extremely  widespreaii 
occurrence  of  the  condition. 
