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A  NATURALIST  ON 
LAKE    VICTORIA 

WITH  AN  ACCOUNT  OF 
SLEEPING  SICKNESS 
AND    THE     TSE-TSE    FLY 


PLATE   I. 
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.        ND    COMPANV 


PLATE  I 

'Planema  tellus  ?  ,  Kome  Island,  L.  Victoria,  12  vm,  1914. 

Caught  by  native. 

2.  Pseudacraea  eurytus    form   terra  ? ,  Damba  Island,  1-15 

IX,  1911. 

3.  PI.  epaea  form  paragea  ?  ,  Bugalla  Island,  24  ii,  1912. 

4.  Ps.  eurytus  form  obscura  ?  ,  Bugalla  Island,  18  ii,  1912* 

5.  PI  macarista  ^ ,  Entebbe,  16  vm,  1910. 

Caught  by  one  of  Dr.  Wiggins'  natives. 

6.  Ps.  eurytus  form  hobleyi  ^  ,  Wema  Island,  1  iii,  1918. 

7.  PI.  macarista  ?  ,  Kome  Island,  29  vi,  1914. 
•"8.  Ps.  eurytus  form  tirikefists  ?  ,  Bugalla  Island,  6  Xil,  1912. 

9.  PL  poggei  $  ,  Bulago  Island,  15  iii,  l9iL\^  J0l^'! 

10.  Ps.  eurytus  form  poggeoides  ?  ,  13  Viii,  1911. 

Caught  by  S.  A.  Neave   near    west  foot   of  Mt.  Elgon,  Eastern 
Uganda. 


A     NATURALIST 
ON    LAKE   VICTORIA 

WITH  AN   ACCOUNT   OF   SLEEPING 
SICKNESS    AND    THE    TSE-TSE    FLY 


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BY 


G.   D.   HALE   CARPENTER 

D.M.,   B.Ch.  (Oxon),  Uganda  Medical  Service 

Fellow  of  the  Linnean,  Entomological,  and  Zoological  Societies 

of  London 


WITH  2  COLOURED   PLATES,  A   MAP, 
CHARTS,     AND      87     ILLUSTRATIONS 


E.    P.    DUTTON    AND    COMPANY 
68 1  FIFTH  AVENUE,  NEW  YORK 


First  published  vi  1920 


(All  rights  reserved) 

PRtNTBD  IK  GREAT  BRITAIN 


TO   THE 
MEMORY   OF  MY  FATHER 

P.    HERBERT   CARPENTER,  D.Sc,  F.R.S. 

AND   TO    MY    DEAR   MOTHER 

THIS,    MY   FIRST   BOOK, 

IS    DEDICATED 


"  It  appeal's  to  me  the  doing  what  little  we  can 
to  increase  the  general  stock  of  knowledge  is  as 
respectable  an  object  of  life  as  one  can  in  any 
likelihood  pursue." 

Letter  from  Charles  Darwin  to  his  sister,  1833. 


INTRODUCTION 

At  the  commencement  of  1910,  when  studjdng  Tropical 
Medicine  at  the  London  School,  I  was  asked  if  I  would 
undertake  an  investigation  into  the  bionomics  of  tho 
Tse-tse  fly,  Glossina  palpalis,  in  Uganda,  as  the  Tropical 
Diseases  Committee  of  the  Royal  Society  had  come  to 
the  conclusion  that  a  greater  knowledge  of  this  fly  was 
essential  for  the  successful  dealing  with  the  disease. 

I  left  England  in  June  1910,  and  during  the  second  half 
of  this  year  and  beginning  of  1911  worked  at  Jinja, 
on  the  north  shore  of  the  Victoria  Nyanja,^  where  the 
Nile  takes  origin,  and  endeavoured  to  famiharize  my- 
self with  the  novel  surroundings  and  with  the  fly. 

It  soon  appeared  that  residence  on  the  completely 
depopulated  islands  known  as  the  Sesse  Isles,  in  the 
north-west  part  of  the  lake,  would  afford  ideal  conditions 
for  studying  Glossina  unaltered  by  the  presence  of  man- 
kind and  his  surroundings  ;  accordingly,  in  February 
1911,  I  went  to  Nsadzi  Isle,  which,  lying  south  of  Entebbe 
and  within  two  or  three  hours  of  it  by  canoe,  had  been 
recommended  by  the  P.M.O.  as  suitable  for  a  beginning. 
This  island,  however,  did  not  furnish  aU  the  conditions 
required  for  the  investigations,  and  camp  was  moved, 
after  a  fortnight,  to  the  large  Island  of  Damba  to  the 
east  and  on  the  Equator,  where  the  rest  of  the  year  was 
spent. 

^  Nyanja,  not  Nyanza.  The  former  is  Luganda  for  lake,  the  latter 
means  nothing,  and  is  erroneously  copied  from  one  book  to  another. 


X  INTRODUCTION 

In  January  1912,  a  new  site  was  chosen  on  Bugalla, 
the  largest  island  of  the  Sesse  group,  lying  in  the  north- 
west corner  of  the  lake,  and  fourteen  months  of  unin- 
terrupted residence  were  spent  there,  after  which  I  went 
home  on  leave,  returning  in  December  1913.  On  arrival 
at  Entebbe  I  met  Mr.  W.  F.  Fiske,  from  the  States, 
who  had  been  deputed  by  the  Tropical  Diseases  Bureau 
of  London  to  investigate  Glossina  morsitans,  and  had 
decided  to  first  make  the  acquaintance  of  palpalis, 
the  problems  connected  with  which  seemed  more 
readily  soluble,  and  by  their  solution  might  throw  light 
on  morsitans.  He  had  decided,  as  a  result  of  several 
months'  previous  work,  to  undertake  a  tour  of  the  chain 
of  islands  lying  parallel  with  the  north  shore  of  the  lake, 
in  order  to  compare  one  with  the  other,  hoping  that  the 
presence  or  absence  of  Glossina  might  be  found  to  be 
correlated  with  definite  factors.  He  proposed  that 
I  should  join  him,  and  we  made  the  tour  together,  very 
greatly  to  my  benefit  not  only  regarding  Glossina  in 
particular,  but  in  field  work  in  general,  his  wide  experi- 
ence of  field  entomology  and  acute  powers  of  observation 
showing  me  how  much  I  had  missed  when  working  by 
myself.  At  the  close  of  a  tour  of  about  two  and  a  half 
months  Fiske  left  for  another  part  of  Uganda,  and  I 
settled  down  on  the  western  spur  of  Kome  Isle  to  carry 
out  a  year's  continuous  cycle  of  experiment  and  observa- 
tion on  the  smaller  islets  within  working  distance 
(Ngamba,  Nsadzi,  Kizima,  Tavu,  Bulago,  Kimmi). 
Unfortunately  this  was  brought  to  an  end  by  the  out- 
break of  war  ;  for  in  August  1914  I  was  called  off  for 
duty  with  the  troops  on  the  Uganda-German  frontier, 
and  subsequently  with  the  Belgian  Northern  column 
under  Colonel  Molitor,  which  invaded  German  East 
Africa  via  Kigezi  and  Ruanda,  to  Tabora,  after  which 
my  duties  took  me  to  various  parts  of  German  East 
Africa  and  Portuguese  East  Africa.     When  released  from 


INTRODUCTION  xi 

active  service  in  November  1918,  I  returned  to  Uganda, 
and  had  a  further  most  interesting  tour  among  the  same 
islands  that  were  visited  with  Mr.  Fiske  in  1914. 

This  book  is  an  attempt  to  give  an  account  of  the 
life  on  the  islands  of  the  Victoria  Nyanja  :  and  very 
nearly  all  the  examples  mentioned  were  met  with  there, 
between  February  1911  and  August  1914.  During  active 
service,  however,  other  examples  were  met  with,  an 
account  of  which  seemed  not  to  be  out  of  place  in  this 
book  because  of  their  bearing  on  certain  of  the  points 
discussed.  The  fascinating  question  of  the  Colouration  of 
Insects  has  been  treated  at  some  length,  but  mainly  from 
the  point  of  view  of  the  bearing  on  it  of  examples  met 
with  on  the  islands.  Consequently  this  chapter  must 
not  be  taken  as  a  discussion  of  the  relative  merits  of 
rival  theories  from  an  abstract,  or  "  arm-chair,"  point 
of  view.  Similarly  the  chapter  on  Glossina  must  not 
be- taken  as  a  complete  summary  of  all  that  is  known, 
since  this  book  deals  almost  entirely  with  some  of 
my  own  observations  and  work. 

The  chapters  on  Mammals,  Birds  and  Reptiles,  I  am 
aware,  are  dreadfully  scanty.  In  defence,  I  can  only 
urge  that  I  am  primarily  an  entomologist ;  and  my 
knowledge  of  field  botany  is  a  minus  quantity  ! 


I  am  indebted  to  the  Royal  Society  and  the  Controller 
of  His  Majesty's  Stationery  Office  for  permission  to 
reproduce  illustrations  and  other  matter  that  have 
appeared  in  my  reports  to  the  Sleeping  Sickness  Com- 
mission. 

The  beautiful  photograph  of  Glossina  is  the  work  of 
Mr.  A.  Robinson,  of  the  Oxford  University  Museum. 

Grateful  acknowledgment  is  also  due  to  the  Council 
of  the  Entomological  Society  of  London,  for  permission 


xii  INTRODUCTION 

to  reproduce  the  two  plates  of  butterflies  which  have 
appeared  in  the  Transactions  for  1920.  Many  of  the 
observations  on  Insects  have  already  appeared  in  the 
publications  of  the  Society,  others  in  Bedrock,  and  some 
of  those  on  the  Fossorial  Hymenoptera  in  the  Journal  of 
the  East  Africa  and  Uganda  Natural  History  Society. 

Mr.  A.  L.  Shephard,  of  the  Tropical  Diseases  Bureau, 
very  kindly  gave  me  references  which  were  of  great  help 
in  the  preparation  of  the  chapters  on  Sleeping  Sickness, 
and  thanks  are  also  due  to  the  Director,  Dr.  A.  G.  Bagshawe, 
C.M.G,,  in  this  matter.  Dr.  H.  Eltringham  most  kindly 
complied  with  a  request  for  the  use  of  his  talent  as  a 
draughtsman,  and  provided  an  original  and  humorous 
drawing  of  an  imaginary  example  of  mammalian  mimicry. 

To  my  friend  and  mentor,  E.  B.  Poulton,  F.R.S., 
Hope  Professor  of  Zoology  at  Oxford,  I  owe  more  than 
I  can  say  for  his  ever  ready  advice  and  encouragement, 
for  his  kindness  in  writing  the  Preface,  and  in 
particular  for  reading  the  MS.  of  Chapter  XI,  and 
suggesting  improvements  therein.  To  him  and  Dr.  S. 
A.  Neave  are  due  the  selection  and  arrangement  of 
specimens  illustrating  by  two  plates  forms  of  Pseudacraea 
eurytus  and  their  models.  Dr.  Karl  Jordan,  of  the  Tring 
Museum,  was  most  kind  in  showing  me  Lord  Rothschild's 
collection  of  this  wonderful  species,  including  a  unique 
specimen  of  a  new  form  which  shows  the  geographical 
range  to  extend  further  southwards  than  has  been 
known   hitherto. 

G.  D.  H.  C. 


PEEFACE 

BT 

PROFESSOR    POULTON 

Every  reader  of  this  book  will,  I  feel  sure,  recognize 
that  it  contains  a  really  wonderful  body  of  observations  ; 
especially  so  if  the  brief  time  in  which  they  were  made 
be  borne  in  mind — from  February  1911  until  the  day 
in  August  1914  when,  without  a  word  of  preparation  or 
a  hint  of  warning,  the  author  arrived  in  Entebbe  to  find 
in  full  progress,  and  to  bear  his  part  in,  the  fiercest  struggle 
of  human  history.  And  even  this  short  period  of  "  island 
life  "  was  broken  into  by  nearly  a  year's  leave. 

The  observations  recorded,  whether  dealing,  now  and 
then,  with  men,  or,  throughout  the  book,  with  other 
animals,  are  both  loving  and  accurate.  The  two  qualities 
are  closely  associated,  for  the  love  of  living  beings  renders 
the  patient  study  of  them  an  unceasmg  fascination  and 
delight. 

Apart  from  the  chapters  on  Sleeping  Sickness  and  its 
carrier,  the  Tse-tse  fly,  the  most  important  discoveries 
are  those  which  add  to  our  knowledge  of  Papilio  dardanus, 
and,  above  all,  the  breeding  experiments  which  brought 
final  confirmation  to  the  conclusions  of  Dr.  Karl  Jordan 
upon  that  wonderful  series  of  mimetic  butterflies  here 
proved  beyond  doubt  to  be  forms  of  a  single  species — 
Pseudacraea  eurytus  of  Linnaeus. 

xiii 


xiv  PREFACE 

It  is  a  curious  fact  that  the  African  butterflies — far 
less  numerous  in  species  than  those  of  the  tropical  East, 
and  outnumbered  even  more  by  the  American — should 
include  what  are  probably  the  two  most  remarkable 
examples  of  mimicry  in  the  world — Papilio  dardanus 
and  Ps.  eurytus  ;  furthermore,  that  they  should  illustrate 
such  different  aspects  of  the  subject. 

The  Swallowtail,  dardanus,  whose  non-mimetic  male 
is  accompanied  by  a  very  similar  non-mimetic  female  in 
Madagascar,  the  Comoro  Islands,  Somaliland,  and  Abys- 
sinia (although  two  single  but  different  mimetic  females 
were  once  taken  in  this  last  locality),  is  represented, 
wherever  it  occurs  on  other  parts  of  the  African  continent, 
by  females  entirely  different  from  males,  and  either 
mimetic  of  other  butterflies,  or,  far  more  rarely,  inter- 
mediates between  these  mimetic  forms,  or  persistent 
stages  enabling  us  to  retrace  the  history  of  their  origin. 
Until  1903  the  mimetic  females  were  all  believed  to 
resemble  the  commonest  Danaine  butterflies  of  each 
locality — often  mimicking  in  a  single  area  three  different 
species  with  widely  different  patterns. 

This  interesting  and  complicated  story  became  still  - 
further  involved,  when,  on  October  7,  1903,  the  late  Mr. 
Roland  Trimen  brought  before  the  Entomological  Society 
an  account  of  a  new  and  entirely  different  female,  mimick- 
ing not  a  Danaine,  but  an  Acraeine  model,  belonging  to 
the  genus  Planema.  For  some  years  the  new  mimic, 
appropriately  named  planemoides,  was  only  by  strong 
inference  assumed  to  be  a  form  of  dardanus,  but  definite 
proof  was  soon  afforded  by  the  study  of  a  specimen 
captured  by  Mr.  T.  T.  Behrens,  R.E.,  near  the  old  southern 
boundary  of  Uganda  on  the  west  shore  of  the  Victoria 
Kyanja.  This  single  example  was,  on  the  left  side,  a 
gynandromorph,  viz.  one  of  those  rare  individuals  in 
which  the  patterns  of  the  two  sexes  occur  combined. 
In  this  case  parts  of  the  yellow  and  black  non -mimetic 


1 


PREFACE  XV 

pattern  of  the  male  are,  as  it  were,  let  into  the  mimetic 
female  pattern,  clearly  proving  that  the  two  belonged 
to  the  same  species.  The  specimen,  now  m  the  Hope 
Collection  of  the  Oxford  University  Museum,  is  figured 
in  the  Transactions  of  the  Entomological  Society  for  1906 
(PI.  XVIII,  Fig.  4). 

The  evidence  of  this  specimen  was  very  satisfactory, 
but  how  much  better  was  the  proof  by  breeding  from  a 
known  parent,  obtained  by  the  author  in  Bugalla  island, 
Sesse  Archipelago,  when  he  captured  on  December  1,  1912, 
a  planemoides  female,  and  reared  from  its  eggs  three 
females  like  the  parent,  seven  of  the  black-and-white 
hippocoon  females,  and  twelve  non-mimetic  males.  And 
later  on,  m  1915,  when  Medical  Officer  to  the  forces  acting 
on  the  southern  frontier  of  Uganda,  he  reared  one  plane- 
moides female,  one  trophonissa  female  (similar  to  hippocoon, 
but  with  the  main  white  areas  replaced  by  orange),  and 
five  males  from  the  eggs  of  a  captured  female  combining 
the  patterns  of  her  two  daughters.  These  are  the  only 
occasions  on  which  the  planemoides  female  has  been  bred, 
although  rare  forms  which  evidently  represent  an  imper- 
fect planemoides,  many  hundreds  of  miles  away  from  its 
model,  have  been  bred  by  Mr.  C.  F.  M.  Swynnerton  in 
S.E.  Rhodesia,  and  by  Mr.  G.  F.  Leigh,  in  the  neigh- 
bourhood of  Durban. 

The  Pseudacraea  mimics,  belonging  to  the  Nymphaline 
sub-family,  and  allied  to  our  own  White  Admiral  {Limenitis 
sybilla),  illustrate  the  second  great  group  of  mimetic 
butterflies  in  which  the  males  resemble  models  as  weU 
as  the  females.  The  models  of  the  Ps.  eurytus  series, 
with  which  this  book  deals,  all  belong  to  the  Acraeine 
genus,  Planema,  but  in  some  of  them  the  sexes  differ, 
while  in  others  they  are  alike.  In  Uganda  there  is  one 
common  example  of  the  first,  mimicked  by  a  Pseudacraea 
whose  male  resembles  the  male  and  female  the  female, 


xvi  PREFACE 

and  also  two  examples  of  the  second,  each  mimicked  by 
a  Pseudacraea  with  sexes  alike  ;  and  when,  in  1910, 
Dr.  Jordan  announced  that  these  three  Pseudacraeas  could 
not  be  separated  structurally  from  each  other,  from  the 
Linnean  West  African  eurytus,  or  from  other  mimics  west, 
east,  and  south,  which  had  been  described  as  distinct 
species,  I  felt  that  the  obvious  conclusion  that  they  were 
in  fact  all  of  them  forms  of  one  and  the  same  species 
ought  to  be  confirmed  by  breeding  experiments  before 
it  gained  acceptance.  And  it  was  the  occurrence,  in  the 
same  area,  e.g.  Uganda,  and  ex  hypothesi  interbreeding, 
of  forms  with  sexes  different  and  with  sexes  alike,  which 
raised  the  greatest  difficulty,  and  at  the  same  time 
would  prove  of  the  deepest  interest  if  the  conclusion 
were  confirmed.  In  order  to  test  it  I  wrote  to 
every  naturalist  known  to  me  who  was  in  a  position 
to  undertake  the  work,  pointing  out  its  exceptional 
interest  and  importance.  I  even  tried  to  persuade  the 
late  Mr.  A.  D.  Millar  who  had  just  been  very  successful 
in  breeding  the  Natal  form  of  the  Pseudacraea,  to  under- 
take the  journey  to  Uganda  and  apply  his  experience 
there. 

The  complete  success  finally  attained  by  the  author 
on  Bugalla  may  be  gathered  from  the  results  fully  set 
forth  in  Chapter  XI.  Dr.  Jordan's  conclusions  were 
thoroughly  confirmed,  and  the  large  group  of  conspecific 
forms,  now  proved  to  interbreed  in  the  same  areas,  and 
interbreeding,  it  may  be  legitimately  inferred,  with  those 
of  other  areas  when  they  meet  on  the  boundaries,  the 
group  of  Pseudacraea  eurytus,  took  its  place  beside  that 
of  Papilio  dardanus  as  one  of  the  greatest  examples  of 
mimicry  in  the  world. 

This  discovery  was  completed  by  another  of  equal 
importance  described  in  the  same  chapter,  the  evidence 
that  the  mimetic  patterns  were  only  kept  up  to  the  mark 
in  islands  where  and  when  their  models  were  relatively 


PREFACE  xvii 

abundant.  As  these  became  scarce,  so  did  the  mhnetic 
Pseudacraeas  run  into  each  other  more  and  more 
completely  through  the  intermediation  of  an  increasing 
number  of  transitional  forms. 

In  concluding  I  should  wish  to  take  this  opportunity 
of  thanking  all  those  naturalists  who,  during  the  past 
quarter  of  a  century,  in  distant  lands,  have  helped  me 
in  my  work  and  have  given  me  the  great  pleasure  of  helping 
them  ;  and,  among  all,  especially  to  thank  the  author. 
Dr.  G.  D.  Hale  Carpenter,  D.M.,  not  only  for  the  mutual 
help  which  may  be  gathered  from  this  book,  but  for 
much  further  help  in  S.W.  Uganda,  and  ex-German  East 
Africa  ;  the  late  C.  0.  Farquharson,  in  S.  Nigeria,  whose 
death  in  the  sinking  of  the  Burutu  almost  at  the  end  of 
the  war,  was  so  great  a  loss  to  Natural  History  ;  W.  A. 
Lamborn,  in  S.  Nigeria,  ex-G.E.A.,  and  now  in  the 
Federated  Malay  States  ;  Dr.  G.  A.  K.  Marshall,  D.Sc, 
C.M.G.,  in  Natal  and  S.  Rhodesia  ;  the  Rev.  Canon  K. 
St.  Aubyn  Rogers,  M.A.,  in  British  and  ex-G.E.A.,  the 
late  R.  W.  C.  Shelford,  M.A.,  in  Borneo,  another  grievous 
loss  to  science  ;  C.  F.  M.  Swynnerton,  in  S.E.  Rhodesia  ; 
and  C.  A.  Wiggins,  P.M.O.,  Uganda,  in  this  country 
and  B.E.A.  To  all  these  and  many  others  I  offer  most 
grateful  thanks  for  some  of  the  greatest  happiness  I 
have  known. 

EDWARD    B.    POULTON. 
August  3,   1920. 


CONTENTS 


Introduction 


PA.OE 

ix 


Preface.    By  Professor  E.  B.  Poulton,  F.R.S. 


.   xui 


CHAPTER 

I.     Sleeping  Sickness      .  .  .  .  . 

Symptoms — Ancient  description — History  of  the 
introduction  of  the  Uganda  epidemic  —  The 
Rhodesian   disease 


II.    Natural  History  op  Sleeping  Sickness    . 
Trypanosomes,  Tse-tse  flies,  and  game 


11 


III.    Natural  History  of  Glossina  palpalis 


30 


IV.     The  Lake         .  .  .  .  .  .67 

Geographical  data — Scenery — Weather — A  storm — 
Weather  prophets — Noises  of  the  night 

V.    Canoes  and  a  Voyage  .  .  .  .84 

Description   of   the   Sesse   canoe,  and  a  voyage  to 
the  southernmost  islands  of  Sesse 


58957 


XX 


CONTENTS 


CHAPTEB  PAGE 

VI.     A  Tour  of  Investigation   among   the   Northern 

Islands       .  .  .  .  .  .94 

A  number  of  islands  compared  as  to  their  fauna 

VII.     Mammals  .  .  .  .  .  .126 

Monkeys  —  Hippos  —  Situtunga  —  Otters  —  Bats — 
Mongoose 

VIII.    Birds 145 

IX.     Eeptiles  and  Fish     .....  180 

X.    The  Colouration  of  Insects  .  .  .  195 

Procryptic  —  Anticryptic  —  Aposematic  —  Directive 
marks — The  habit  of  grouping  together  more 
common  in  aposematic  than  procryptic  species 
— Enemies  of  protected  insects — Sexual  colouring 
and  coiu-tship  of  butterflies  —  Mimicry,  Batesian 
and  Mullerian — Do  birds  eat  btatterflies  ? — Longley's 
revised  hypothesis  of  mimicry 

XI.       FSEUDACRAEA    EURYTUS  ....    242 

Some  of  its  forms  and  varieties  and  their  bearing 
on  the  interpretation  of  mimicry  by  natural 
selection 

XII.    Hymenopteea  .....  276 

Ants — Wasps — Fossors  or  Sand-wasps — Bees 

XIII.     Sundry  Insects  .....  305 

Beetles  —  Di-agon-flies  —  Montispa  —  Mantidae — 
Grasshoppers  —  Cockroaches  —  Earwigs  —  Flies — 
Spiders — Myriapods — Crustacea — Molluscs 


LIST   OF  ILLUSTRATIONS 


Plate  I.  Model  species  of  Planema  with  mimetic  forms  of  Pseuda- 

craea  eurytus  (coloured  plate)         ....  Frontispiece 

FACING  PAGE 

Plate  II.  Model  species  of  Planema  with  mimetic  forms  of  Pseuda- 

craea  eurytus  (coloured  plate)         ......  244 

Fly  beach  on  Damba  Isle  ........  24 

Fly  beach  on  Bugalla  Isle            .......  24 

On  Damba  Isle  ;   not  a  good  fly  shore          .....  30 

A  fly-boy  at  work      .........  30 

An  Ambatch  tree        .........  48 

Fly  beach  on  Kimmi            ........  48 

Glossina  palpalis  and  pupae         .......  54 

Uprooted  tree  on  Kimmi  Isle  forming  ideal  shelter  for  pupae  .  .  54 
Searching  for  pupae  among  grass  tussocks  on  south  point,  Bulago 

Isle 54 

Tree  trunk  on  Bugalla  Isle  under  which  many  Glossina  pupae  could 

always  be  found            ........  56 

Breeding  place  of  Glossina  at  hollowed  base  of  tree  on  Bugalla     .  56 

"  Enzibaziba  "  bushes  on  Damba  Isle  forming  breeding  ground  .  58 
Shingle  and  sand  under  sheltering  Enzibaziba  bushes  where  flies 

have  been  seen  to  deposit  larvae            .....  58 

The  first  artificial  breeding  ground,  on  Ngamba  Isle    ...  62 

Artificial  breeding  ground  on  Tavu  Isle        .....  62 

The  Kagera  river        .  .  .  .  .  .  .  .  .68 

The  head  of  Napoleon  gulf  where  the  Nile  arises  from  the  Lake  .  68 

The  eastern  cataract  of  the  Ripon  falls        .....  68 

The  birth  of  the  Nile 68 

Young  Raphia  palm  .........  70 

Wild  date  pahn 70 

A  tangled  mass  of  Ipomaea  in  flower            .....  70 

A  bed  of  bracken  on  Bugalla      .......  70 

Abrupt  margin  of  forest  belt  on  Bugalla     .....  72 

Park  land  on  Bugalla          ........  72 


XXll 


LIST   OF   ILLUSTRATIONS 


My  settlement  on  Bugalla  Isle,   1912-13 

Aerial  roots  dipping  to  ground,  Bugalla  forest 

Giant  twisted  stem  of  creeper,  Bugalla  forest 

Canoe  returning  with  load  of  firewood 

A  canoe  race      ..... 

A  halt  on  the  east  coast  of  Bugalla   . 

Pitching  camp  on  the  isthmus  of  Kirugu  Isle 

The  western  point  of  Kirugu  Isle 

On  Kirugu  Isle 

On  Kirugu  Isle 

The  high  ridge  of  Kuye  Isle 

South  end  of  Buguye  Isle 

South  end  of  Nkose  Isle     . 

Canoe  off  Kirugu  Isle 

Bulago  Isle,  north  bay  and  forested  north  point 

The  open  grass  land  interior  of  Bxilago 

Large  fig  tree  on  Ngamba  Isle 

Nsadzi  Isle,  south  beach     . 

Dwasendwe  from  Dwanga  Mto, 

Kisigalla  Islet     . 

South  beach  of  Nsadzi  Isle 

South-west  end  of  Wema  Isle 

View  South-east  from  Bugalla  camp    . 

Wee  Man  choosing  a  grasshopper 

Wee  Man  and  Tommy  taking  grasshoppers 

Wee  Man  being  rude  to  a  Tortoise 

Tommy  and  Wee  Man  in  an  interval  of  a  game 

Puffin  "  hating  "  a  Tortoise 

A  favourite  haunt  of  Situtunga  on  Bugalla 

A  bat  caught  on  tent  at  Jinja 

Nest  of  Egjrptian  goose 

Nest  of  stone  curlew 

Nest  of  stone  curlew 

Nest  of  Osprey 

View  from  camp  on  Kome 

View  towards  Buvumira  from  Bugalla  camp 

Nesting  place  of  kingfishers 

Fly-catcher 

Nest  of  crocodile 

Canoe-man  with  Enswa-swa 

A  small  Enswa-swa    . 

A  very  abundant  tree  frog 

Fly-boy  and  Mamba 

Semutundu    .    . 


FACING  PAGE 

74 

78 

78 

84 

86 

86 

88 

88 

90 

90 

90 

90 

92 

92 

94 

94 

98 

100 

106 

106 

106 

106 

118 

132 

132 

134 

134 

136 

142 

142 

150 

150 

152 

160 

166 

166 

170 

174 

174 

182 

190 

190 

192 

192 


LIST   OF   ILLUSTRATIONS 


XXlll 


Male  .... 

Caterpillar  of  Aterica  galenc 

Pupae  of  Papilio  dardanus 

Moth  at  rest  on  low  foliage 

Aposematic  caterpillars 

Diagram  of  ant  and  typical  spider 

Imaginary  case  of  Mammalian  mimicr 

"  Toby  "  as  a  caterpillar  (Pseudacraea  eurylus) 

"  Toby  "  as  a  chrysalis  {Pseudacraea  eurytus) 

View  to  the  West  from  Bugalla  camp 

House  on  Bugalla,   1912-13 

Interior  of  Bugalla  house    . 

Back  of  house  on  Kome  Isle,  1914 

Front  of  Kome  house 

Fly-boys'  camp  on  Kome  Isle,   1914 

Servants'  huts  on  Kome  Isle,   1914 

Cook's  hut  and  kitchen  on  Bugalla 

Personal  boys  and  their  wives     . 


PACING  PAGE 

192 

196 
198 
198 
206 
228 
228 
262 
262 
278 
282 
282 
292 
292 
304 
304 
314 
314 


CHARTS 


I.  Comparison  between  climates  of  Entebbe  and  Bugalla  Isle 
II.  Influence  of  climate  on  flies  at  Jinja  .... 

III.  Influence  of  climate  on  the  fly    . 

IV.  Influence  of  climate  on  rate  of  reproduction  of  the  fly 


V.  Number  of  female  flies  on  different  islands 
VI.  Nmnber  of  male  flies  on  different  islands     . 
VII.  Number  of  crocodiles  and  flies  on  Tavu  island 


40 
42 
44 
46 

At  end  behind  map 


TABLES 

Parallelism  of  Nagana  and  Sleeping  Sickness        .  .  .  . 

Prolonged  catching  of  flies  increases  proportion  of  females  caught 

Proof  that  the  fly  roams  along  the  coast     . 

Sources  of  non-mammalian  blood  found  in  wild  flies 

Flies  watched  biting  captive  crocodile 

Number  of  butterflies  on  various  islands 

Food  of  Bee-eaters     ...... 

Numbers  of  eggs  in  nests  of  crocodiles 

Degrees  of  relationship  between  model  and  mimic 


PAQE 

25 

31 

33 

37 

38 

125 

172 

182 

233 


xxiv  LIST   OF  ILLUSTRATIONS 

PAGE 

Some  forms  of  Pseudacraea  eurytus,  their  models,  and  distribution     254 
Pseudacraea  eurytus  on  Damba  Island  .....      257 

Forms  of  Ps.  eurytus  obtained  by  breeding  from  laiown  parent 
Models,  mimics,  and  intermediates  in  varying  proportions     . 
The  same  shown  graphically  as  a  chart        .... 
Models  and  mimics  in  different  localities      .... 


264 
265 
267 
274 


MAP 

The  Sesse  Archipelago         .  .  .  .  .  -  .    At  the  end 


A    NATURALIST    ON 
LAKE   VICTORIA 

CHAPTER    I 

SLEEPING  SICKNESS 

In  this  chapter  a  general  account  will  be  given  of  the 
history  and  symptoms  of  Sleeping  Sickness  as  it  was 
known  during  the  epidemic  in  Uganda.  It  may  be  said 
at  once  that  the  disease  is  entirely  confined  to  tropical 
Africa,  nor  does  there  seem  any  reason,  as  will  be 
explained  later,  to  fear  its  spread  beyond  Africa. 

In  a  few  words  it  may  be  said  that  the  cause  of  the 
disease  is  a  minute  unicellular  creature,  called  a  Trypano- 
some,  belonging  to  the  lowest  order  of  animal  life,  which 
is  as  it  were  inoculated  by  the  bite  of  a  blood-sucking 
fly,  the  "  Tse-tse,"  or  Glossina. 

A  common  history  given  by  patients  who  suffer  from 
Sleeping  Sickness  is  that  they  have  been  in  a  country 
where  they  were  much  bitten  by  Tse-tse  flies,  and  that 
after  a  few  days  a  painful  swelling  has  appeared  on  the 
neck,  accompanied  by  high  fever.  The  swelling  may 
appear  to  be  on  the  point  of  becoming  an  abscess,  but  does 
not  do  so,  and  gradually  subsides.  It  is  probable  that 
this  represents  the  site  where  the  fly  which  was  the 
cause  of  the  infection  actually  bit.  The  fever  may 
subside  in  a  few  days,  and  recurs  at  irregular  intervals 
lasting  weeks  or  months  :  it  often  reaches  a  high  point 
attended  with  delirium. 

2  1 


2  SLEEPING  SICKNESS 

There  is  a  good  deal  of  headache,  debility  and  languor, 
and  vague  pains  in  legs.  An  interesting  feature  is  the  ap- 
pearance of  an  erythematous  rash,  mainly  on  the  chest 
and  back.  There  is  great  wasting  and  enlargement 
of  the  glands  of  the  neck.  Another  interesting  feature  is 
puffy  swelling  of  parts  of  the  face  and  body  :  this  (ede- 
matous swelling  is  a  particular  feature  of  the  diseases 
of  animals,  which  are,  as  will  be  seen,  so  very  closely 
connected  with  Sleeping  Sickness. 

This  condition  may  go  on  for  years,  and  has  been 
known  to  disappear  altogether  with  an  apparent  cure  ; 
it  is  known  as  "  Trypanosomiasis."  Next  comes  the 
stage  to  which  the  term  "  Sleeping  Sickness "  more 
properly  applies.  The  drowsiness  becomes  accentuated, 
so  that  the  subject  takes  no  interest  in  his  surroundings 
and  does  not  trouble  to  eat,  though  he  will  eat  food 
if  it  is  brought  him,  and  he  is  fed.  The  fever  continues 
irregularly,  the  eyes  become  more  pufEy,  the  lips  and 
tongue  tremulous,  the  wasting  more  and  more  pro- 
nounced, until  death  finally  supervenes  with  the  patient 
in  a  state  of  coma.  At  the  last  there  may  be  mania 
and  convulsions. 

It  has  been  noticed  that  natives  suffering  from  Sleeping 
Sickness  appear  to  feel  the  cold  very  acutely,  and  will 
often  sleep  so  near  to  a  fire  that  they  inflict  severe  burns 
on  themselves.  This  also  shows  how  the  senses  are  dulled, 
so  that  one  can  conclude  that  they  cannot  suffer 
much. 

Death  may  occur  in  a  few  months  after  the  initial 
fever,  but  more  usually  after  one  to  three  years. 

The  earliest  account  of  Sleeping  Sickness  which  is 
known  in  print  dates  from  1742,  and  is  of  considerable 
interest  because  it  reflects  the  current  medical  opinion 
of  the  day. 

Dr.  E.  D,  Whittle,  in  the  Malay  Medical  Journal 
for  April    1911,   drew  attention   to  a   book   by  a   naval 


EARLIEST  ACCOUNT  OF  SLEEPING  SICKNESS   3 

surgeon   named    John   Atkins,    called   Physical   Observa- 
tions on  the  Coast  of  Gainey. 

The  following  extract  is  given  in  The  Sleeping  Sickness 
Bulletin  : 

"  The  Sleepy  Distemper  (common  among  negroes) 
gives  no  other  previous  Notice,  than  a  Want  of  Appetite 
two  or  three  Days  before  :  Their  Sleeps  are  sound,  and 
Sense  of  Feeling  very  little  ;  for  pulling,  drubbing,  or 
whipping,  will  scarce  stir  up  Sense  and  Power  enough 
to  move  ;  and  the  moment  you  cease  beating,  the  Smart 
is  forgot,  and  down  they  fall  again  into  a  state  of  Insen- 
sibility, driveling  constantly  from  the  Mouth,  as  if  in  a 
deep  Salivation  ;  breath  slowly,  but  not  unequally,  nor 
snort. 

**  Young  People  are  more  subject  to  it  than  the  Old  ; 
and  the  Judgement  generally  pronounced  is  Death, 
the  prognostick  seldom  failing.  If  now  and  then  one 
of  them  recovers,  he  certainly  loses  the  little  Reason  he 
had  and  turns  Ideot. 

"  The  immediate  Cause  of  this  deadly  Sleepiness  in 
the  Slaves,  is  evidently  a  Super-abundance  of  Phlegm 
or  Serum  extravated  in  the  Brain,  which  obstructs  the 
Irradiation  of  the  Nerves  ;  but  what  the  procatartick 
Causes  are,  that  exert  to  this  Production,  eclipsing  the 
Light  of  the  Senses,  is  not  so  easily  assigned. 

"  We  find  sometimes  in  Europe  that  Enormities  in 
the  Non-Naturals,  Surfeiting  and  Drunkenness  do  gradu- 
ally, as  Age  and  Custom  advance,  weaken  the  Tone  of 
the  Brain,  to  the  Admission  of  serous  and  extrementitious 
Humours,  including  Sleepiness,  etc.  But  here  the  Case 
is  different,  they  being  young  People  that  are  generally 
afflicted,  and  who  have  been  destitute  of  the  Means  of 
Surfeiting. 

"  I  shall  ascribe  the  Cause  to  catching  Cold,  and  their 
Immaturity  ;  to  Diet  and  Way  of  Living  ;  and  to  the  natural 


4  SLEEPING  SICKNESS 

WeaTcness  of  the  Brain  ;  some  or  all  of  these  Causes  co- 
operating to  it. 

"  First.  In  Immaturity ,  or  Childhood,  it  is  a  common 
and  true  Observation,  that  more  of  Phlegm  and  recre- 
mentitious  Humour  is  bred,  than  at  Manhood  ;  because 
the  Fibres,  and  consequently  the  Faculties  resulting 
from,  their  Constitution,  have  not  attained  their  due 
Spring  and  Perfection ;  and  it  is  only  supposing  the 
Africans  continue  longer  Children  than  the  Europeans. 

"  Secondly.  Promoted  here  by  their  Diet  and  Way  of 
Living.  At  Home  it  is  mostly  on  Roots,  Fruits,  and 
Herbage,  greedily  devouring  such  as  are  wild  and  uncul- 
tured ;  which,  together  with  the  intolerable  Heats  of  the 
Sun,  weakening  the  concoctive  Faculty,  together  with 
their  Inactivity,  render  a  very  recrementitious  Nutriment  : 
Their  Indolence  is  such  (when  shipped  on  Board  for  Slaves) 
as  to  be  entirely  dispassionate  at  parting  with  Wives, 
Children,  Friends,  and  Country,  and  are  scarcely  touched 
with  any  other  Sense  or  Appetite,  than  that  of  Hunger  ; 
and  even  in  this,  for  want  of  Custom  or  Instinct,  they 
cannot  distinguish  proper  Food,  nor  know  when  to  leave 
off,  voraciously  eating  though  Victuals  be  never  so  dirtily 
cook'd  ;  and  whether  the  Flesh  be  raw  or  dressed,  whether 
of  the  Guts  or  a  Sirloin  ;  a  Practice  also  that  may  sometime, 
by  over-stretching  the  Fibres  of  the  Stomach,  occasion 
Crudity  and  indigestion.  By  their  Sloth  and  Idleness 
the  Blood  becomes  more  depauperated  ;  and  those  recre- 
mentitious Humours  bred  from  it,  that  Exercise  would 
throw  off  through  the  proper  secretory  Organs,  are  here 
disposed  towards  the  weakest  Part,  which  in  the  Gener- 
ality of  Negroe  Slaves  I  take  to  be  the  Brain. 

"  Thirdly,  The  natural  Weakness  of  the  Brain,  I  am  apt 
to  think  the  principal  Cause  of  the  Distemper.  Doubt- 
less that  Part  gains  Strength  by  Exercise,  i.e.  by  the 
Employment  of  our  rational  Faculties,  as  well  as  the 
Muscles  and  external  Fibres  of  the  Body  by  Labour  ; 


EARLIEST  ACCOUNT   OF  SLEEPING  SICKNESS   5 

and  since  the  Africans  are  hereditarily  ignorant,  destitute 
of  all  Art  and  Science,  or  any  mechanical  Knowledge  to 
exercise  the  Brain,  it  consequently  grows  weaker  in  its 
inward  Structure  and  Recesses  ;  and  falls  together  with 
the  Judgement  and  Passions. 


"  The  Cure  is  attempted  by  whatever  rouzes  the  Spirits  ; 
bleeding  in  the  Jugular,  quick  Purges,  Sternutories, 
Vesicatories,  Acu-Puncture,  Seton,  Fontanels,  and  sudden 
Plunges  into  the  Sea,  the  latter  is  most  effectual  when 
the  Distemper  is  new,  and  the  Patient  not  yet  driveling 
at  Mouth  and  nose."  ^ 

Noteworthy  in  this  account  are  the  number  of  causes 
assigned  to  this  mysterious  disease,  and  the  naive  way 
in  which  the  author  assigns  the  conditions  to  "  some 
or  all  of  these  causes  "  ! 

The  essential  characteristics  of  the  disease  in  an  advanced 
stage  are  all  noted  ;  the  "  Indolence,"  "  State  of  Insensi- 
bility," ''Hunger,"  ''Sense  of  Feeling  very  little," 
but  the  preliminary  stages  were  not  noted,  for  Atkins 
says  it  gives  no  other  notice  than  a  want  of  appetite  two 
or  three  days  before  ! 

With  the  aid  of  a  little  imagination  one  can  see  a 
terrible  picture  of  these  wretched,  somnolent  natives 
being  subjected  to  "  pulUng,  drubbing  or  whipping  "  in 
the  endeavour  to  give  them  sufficient  "  Exercise "  to 
"  throw  off  the  recrementitious  Humours  "  and  afterwards 
"  voraciously  eating  though  Victuals  be  never  so  dirtily 
cook'd  "  ! 

The  "  Sudden  Plunges  into  the  Sea "  are  not  used 
for  curing  Sleeping  Sickness  at  the  present  day  ! 

^  The  Navy  Surgeon  :  or  Practical  System  of  Surgery  ivith  a  Disserta- 
tion on  Cold  and  Hot  Mineral  Springs  and  Physical  Observations  on  the 
Coast  of  Guiney,  by  John  Atkins,  Surgeon.  London  ;  Printed  for  J. 
Hodges,  at  the  Looking  Glass,  over  against  St.  Magnus  Church,  London 
Bridge.   aiDCCXLII.   pp.    364-7. 


6  SLEEPING  SICKNESS 

It  was,  I  believe,  well  known  to  the  African  slave 
traders  that  natives  with  enlarged  glands  were  of  no  use 
to  them,  as  they  always  died  and  could  not  be  made  to 
work.  So  they  were  careful  not  to  take  any  in  this 
condition,  but  nevertheless  took,  without  knowing  it, 
many  cases  who  had  the  earliest  stages  of  the  disease, 
and  the  American  slave-owners  used  to  find  their  slaves 
dying  of  this  peculiar  drowsiness. 

Yet  it  was  not  infectious,  that  is,  it  was  not  communi- 
cated from  one  to  another  :  the  reason  for  this  will  be 
entered  into  more  fully  further  on. 

In  1890,  a  French  doctor  discovered  in  the  blood  of 
a  patient  from  Africa  who  was  suffering  from  a  peculiar 
fever,  a  microscropic  organism  which  he  recognized  as 
a  Trypanosome,  but  he  did  not  establish  any  relation 
between  this  and  the  fever,  and  the  credit  of  first  dis- 
covering this  belongs  to  an  Englishman.  In  1901  Dr. 
Forde,  in  the  Gambia  colony  on  the  West  Coast,  had 
an  English  patient  with  a  peculiar  fever  of  a  chronic 
and  irregular  type.  He  found  in  the  blood  a  curious 
organism  whose  nature  he  could  not  recognize,  and 
called  in  the  late  Dr.  Dutton,  who  at  once  recognized 
the  creature  as  a  Trypanosome  ;  ^  the  first  one  to  be 
discovered  in  man,  though  one  had  been  described  as 
the  cause  of  a  disease  in  horses  in  India  some  ten  years 
before. 

At  first,  and  for  some  time,  Sleeping  Sickness  was  only 
known  to  occur  in  West  Africa,  but  when  equatorial 
Africa  was  gradually  opened  up  the  disease  found  its 
way  into  Uganda  with  disastrous  results. 

This  is  believed  to  be  due  to  Stanley's  expedition  for 
the  relief  of  Emin  Pasha,  which  in  1888  travelled  from  the 
Congo  to  the  Lake  Albert  Nyanza.  In  1891  the  Sudanese 
soldiers  of  Emin's  force  were  brought  into  South  Toro 

1  British  Medical  Journal,  1902,  January  4th,  p.  42,  and  November  29th, 
p.   1741. 


THE   UGANDA   EPIDEMIC  7 

with   their  followers,  and  eventually  were  brought  into 
Uganda  itself  to  be  under  control. 

In  July  1901,  Dr.  Albert  Cook  of  the  Church  Missionary 
Society  at  Mengo  (Kampala)  noted  eight  cases  of  a  mys- 
terious disease,  and  six  months  later  reported  that  on 
Buvuma  Island  over  two  hundred  natives  had  died  and 
thousands  appeared  to  be  infected.  The  mortality 
became  appalling,  and  the  Government  were  at  their 
wits'  end,  for  it  seemed  as  if  the  whole  population  was 
doomed. 

In  July  1902,  the  first  Royal  Society  Commission  arrived 
in  Uganda,  composed  of  Drs.  Low,  Christie,  and  Castellani, 
and  Colonel  Sir  David  Bruce  arrived  in  February  1903. 
On  April  28th,  it  was  announced  that  the  disease  was 
caused  by  a  Trypanosome  and  conveyed  by  a  Tse-tse  fly, 
Glossina  palpalis.^ 

It  was  suggested  at  once  that  as  the  haunts  of  this 
fly  were  strictly  limited,  it  would  be  easy  to  check  the 
disease  by  removing  the  population  ;  ^  but  the  natives, 
with  their  characteristic  fatalism,  refused  to  leave  their 
villages  along  the  shores  of  the  lake.  In  the  mean- 
time the  disease  raged  unchecked,  and  by  the  end  of  1903 
the  number  of  deaths  had  reached  over  90,000  ;  whole 
villages  were  being  depopulated,  and  great  tracts  of 
highly  cultivated  country  relapsed  into  scrub  and  forest. 

In  March  1905  Lieutenant  Tulloch,  R.A.M.C,  who 
had  been  sent  out  by  the  Royal  Society  to  help  in  the 
investigations,  became  infected  with  the  disease  in  its 
virulent  form,  and  died  a  few  months  later. 

By  November  1904  the  epidemic  had  appeared  on 
the  shores  of  Lake  Albert  in  North-West  Uganda,  and  a 
survey  of  Uganda  by  six  specially  appointed  medical 
officers  in  1905  showed  that  the  banks  of  the  lakes  and 


^  Reports   of   Sleeping    Sickness    Conunission    of   the    Royal    Society, 
1903,  Nos.  I,  IV. 
*  See  Bulletin  of  Sleeping  Sickness  Bureau,  vol.  4,  pp.  241-2. 


8  SLEEPING  SICKNESS 

watercourses  throughout  Uganda  were  infested  with 
the  Tse-tse  fly. 

Statistics  furnished  in  a  dispatch  by  the  Governor 
showed  that  "  during  the  last  five  years  the  total  mor- 
tality from  this  scourge  in  this  Protectorate  has  consider- 
ably exceeded  200,000."i 

Sir  Hesketh  Bell  also  reported  *'  the  natives  have  been 
almost  completely  wiped  out  everywhere  along  the  lake 
shore,  and  in  the  islands  the  mortality  has  been  even  more 
appalling.  Buvuma,  for  instance,  which  a  few  years  ago 
was  one  of  the  most  thickly  populated  and  prosperous  of  all 
the  islands,  counted  over  30,000  inhabitants.  There  are 
now  barely  14,000.  Some  of  the  Sesse  group  have  lost 
every  soul  ;  while  in  others  a  few  moribund  natives, 
crawling  about  in  the  last  stages  of  the  disease,  are  all 
that  are  left  to  represent  a  once  teeming  population." 

In  November  1906,  it  was  again  suggested  that  the 
only  way  to  save  the  people  was  to  remove  them  into 
fly-free  areas,  and  segregate  the  infected  natives  into 
camps.  The  aid  of  the  chiefs  was  sought  and  the  matter 
fully  explained  to  them,  compensation  was  made  to  the 
heads  of  evicted  families,  they  were  given  land  away 
from  the  infected  areas,  and  by  degrees  not  only  the 
mainland  shores  of  the  lake,  but  the  islands  also,  were 
cleared  of  their  population,  so  that  by  1909  all  these  were 
deserted  and  going  back  to  the  wild  state. ^ 

Great  difficulty  was  experienced  in  preventing  the 
natives  from  returning  to  their  homes,  and  some  managed 
to  obtain  canoes  and  cross  back  to  Buvuma  and  Damba 
Islands,  but  at  length  the  evacuation  was  finally  completed, 
and  at  the  present  day  the  whole  of  the  fertile  and  valuable 
island  territory  is  abandoned  to  the  Tse-tse  fly. 

But  the  lake  shore  can  only  be  kept  in  this  condition 
by  stringent  regulations  and  penalties,  and  a  few  natives 

1  Dispatch  No.   218  from   Sir  Hesketh   Bell,   November   1906. 

2  See  Bulletin  of  the  Sleeping  Sickness  Bureau,  vol.  4,  pp.  241-2. 


THE   RHODESIAN  DISEASE  9 

are  frequently  discovered  in  the  forbidden  areas  by  the 
patrolling  canoes. 

By  these  means  the  inhabitants  of  Uganda  were  saved, 
and  at  the  present  day  there  are  very  few  deaths  a  year  ; 
from  1905-1917  there  were  just  over  30,000  deaths  for 
the  whole  of  the  Uganda  Protectorate. 

At  the  end  of  1909  considerable  alarm  was  caused 
by  the  discovery  in  Nyassaland  of  Sleeping  Sickness 
(or  rather.  Acute  Trypanosomiasis)  in  a  native  there, 
and  since  then  a  number  of  cases  have  been  found,  some 
of  them  Europeans,  in  Nj^'assaland,  North-East  Rhodesia, 
and  Portuguese  East  Africa  :  in  the  case  of  some  natives, 
they  had  certainly  never  left  their  homes.  This  was 
very  interesting  from  a  scientific  point  of  view,  because 
Glossina  palpalis,  the  species  of  Tse-tse  which  carries 
Sleeping  Sickness  in  Uganda  and  the  West  Coast,  does 
not  exist  in  those  countries. 

It  was  soon  found  that  the  carrier  was  another  species, 
namely,  the  very  one  which  has  been  so  long  known  to 
travellers  in  Africa  as  the  cause  of  Tse-tse  fly  disease  or 
"  Nagana  "  of  horses,  cattle  and  dogs. 

This  species  is  known  as  Glossina  morsitans.^ 

As  this  new  form  of  human  Trypanosomiasis  appeared 
to  be  very  much  more  acute  than  the  form  known  as 
Sleeping  Sickness,  the  discovery  was  disconcerting.  It 
is,  however,  possible  that  our  ideas  of  the  severity  of 
this  form  of  Trypanosomiasis  will  need  to  be  modified 
in  the  light  of  further  knowledge,  for  during  the  campaign 
in  East  Africa  a  number  of  natives  were  found  to  have 
Trypanosomes  in  their  blood  while  under  treatment 
for  other  complaints,  and  appeared  to  be  little  the  worse 
for  their  presence  ;  these  natives  had  not  been  in  the  area 
of  Glossina  palpalis,  so  that  either  the  Trypanosome  was 
gambiense  carried  by  morsitans,  or  else  it  was  rhodesiense 

^  Kinghorn  and  Yorke,  Annals  of  Tropical  Medicine  and  Parasitology, 
1912,  vol.  6,  pp.   1-23. 


^^  SLEEPING   SICKNESS 

in  a  non-lethal  form.  It  is  of  interest  to  note  here  that 
a  case  of  true  Rhodesian  Trypanosomiasis  has  recently 
been  recorded  as  the  first  to  be  cured  by  treatment ; 
hitherto  this  form  had  always  been  regarded  as  fatal.i 

vLt  ^^^''^''^.^■J-^ode^iense  infection  which  recovered.  Daniels  and 
Newham,  British  Medical  Journal,  1919,  November  8th,  p.  829. 


CHAPTER  II 

NATURAL  HISTORY  OF  SLEEPING  SICKNESS 

I  PROPOSE  now  to  deal  at  greater  length  first  with  the 
Trypanosomes  and  next  with  the  Tse-tse  flies,  then  the 
inter-relation  of  the  two  will  be  considered  and  the  relation 
of  both  to  the  wild  animals  of  the  countries  in  which 
they  occur. 

Trypanosomes  are  not  "  microbes "  in  the  accepted 
sense  of  the  word  as  commonly  used  ;  that  is,  they  are  not 
micro-fungi,  but  belong  to  the  Protozoa,  the  lowest  members 
of  the  animal  kingdom.  The  Protozoa  can  be  divided 
into  four  main  groups,  in  each  of  which  are  found  species 
causing  disease  in  man  and  other  vertebrates.  The 
Sarcodina  is  exemplified  by  the  well-known  Amoeba  and 
the  species  known  as  Entomoeha,  which  causes  dysentery. 

The  next  group,  Mastigophora,  is  the  one  with  which 
we  are  most  concerned  at  the  moment,  since  to  it  belong 
the  Trypanosomes  and  their  allies.  The  name,  which 
means  "  Whip  Bearers,"  refers  to  the  possession  of  one 
or  more  lashes  or  Flagella,  which  by  their  rapid  move- 
ments draw  or  push  the  animal  through  the  fluid  in 
which  it  lives. 

The  third  great  group  of  Protozoa  is  the  Sporozoa,  which 

is  only    too   familiar   through   the   various    species    that 

cause  malaria.     To  the  last  group   Infusoria  belong   the 

myriad    forms    which    are    the    delight   of   the    amateur 

microscopist  and  may  be  seen  so  easily  in  stagnant  water. 

One  species,  Balantidium,  is  a  cause  of  dysentery. 

11 


12     NATURAL  HISTORY  OF  SLEEPING  SICKNESS 

Let  us  now  look  a  little  more  closely  at  the  MastigopTiora. 
The  group  is  divisible  into  six  sub-groups, ^  but  only  that 
which  includes  the  Trypanosomes  need  be  mentioned 
here.  This  is  named  Protomonadina,  and  includes  the 
following  genera  : 

1.  Trypanosoma. — There   is   a   single   flagellum   arising 

near  the  posterior  nucleus  and  continued  forwards 
as  a  marginal  flagellum  of  an  undulating  mem- 
brane ;  usually  continued  into  a  free  flagellum. 
The  species  are  found  mostly  in  blood  and  in  the 
digestive  tracts  of  invertebrates,  but  are  also  forms 
in  the  life  cycle  of  species  wholly  parasitic  in 
insects. 

2.  Trypanoplasma. — There  are  two  flagella,  the  posterior 

one  united  to  the  body  by  an  undulating  membrane 
along  most  of  its  length.  According  to  their 
mode  of  life  they  fall  into  three  groups. 

1.  Parasites  in  the  blood  of  fresh- water  fish 
and  in  the  digestive  tract  of  leeches. 

2.  Parasitic  in  the  digestive  tract  of  marine 
fishes. 

3.  Parasitic  in  invertebrates. 

3.  Crithidia. — A  single  flagellum  arises  about  the  middle 

of  the  body  and  runs  forwards  to  form  the  marginal 
flagellum  of  a  short  or  rudimentary  undulating 
membrane,  and  is  continued  beyond  as  a  free 
flagellum. 

Crithidia  occur  as  parasites  in  the  gut  of  insects 
or  as  a  stage  in  the  life  cycle  of  a  Try- 
panosome. 

4.  Lepfomonas    or    Herpetomonas. — There    is    a    single 

anterior  flagellum  but  no  undulating  membrane. 
These  are  parasitic  on  invertebrates,  chiefly 
insects,  but  also  occur  as  a  form  of  the  next  genus 

^  This  classification  is  taken  from  Minchin. 


TRYPANOSOMES  18 

in  invertebrate  hosts  or  in  artificial  cultures.  It 
is  also  of  great  interest  that  they  are  found  in  the 
milky  juice  of  certain  plants  (EupJiorbiaceae). 
.  5.  Leishmania. — There  is  no  flagellum,  but  there  are 
two  nuclei  as  in  the  other  genera.  These  animals 
have  become  specialized  to  live  in  the  tissue  cells 
of  vertebrates  and  so  have  no  need  of  organs  of 
locomotion.  It  is  of  much  interest  that  in  arti- 
ficial cultures  Leishmania  develops  into  forms  like 
the  two  preceding  genera  or  like  Trypanosomes. 
The  type  species  causes  a  fatal  disease  in  Asia 
known  as  "  Kala-azar." 

Now  let  us  consider  a  little  more  fully  the  Trypanosomes 
themselves.  They  are  elongated  bodies  with  a  pointed 
posterior  extremity  where  is  a  small  nucleus,  and  at  the 
anterior  extremity  the  whip-like  flagellum  which  by  vigor- 
ous movements  drags  the  Trypanosome  along.  The 
undulating  membrane  pursues  a  wavy  course  along  the 
body  and  is  responsible  for  the  name,  which  is  derived 
from  rpvTTavov,  meaning  a  carpenter's  tool  :  the  allusion 
is  probably  to  the  spiral  thread  on  an  auger.  In  the 
middle  of  the  body  is  a  large  nucleus.  T.  gambiense 
in  the  blood  is  several  times  as  long  as  the  diameter  of  a 
red  corpuscle,  but  much  narrower.  The  different  species 
that  may  be  found  in  the  blood  vary  very  greatly  in  size 
and  activity ;  gambiense  is  not  very  active  and  merely 
wriggles,  but  a  species  such  as  vivax  in  goats  can  hardly 
be  kept  in  the  field  of  a  microscope.  The  first  one  to 
be  seen  was  found  in  the  blood  of  a  frog,  but  the 
first  reliable  description  was  not  given  until  1841,  when 
a  specimen  was  described  from  the  blood  of  a  trout. ^ 
Not  until  1879  was  one  found  in  a  mammal,  and  this  was 
Trypanosoma  lewisi,  seen  in  the  blood  of  the  rat.     It  is 

1  By  Valentin.  Recent  work  by  Mile.  M.  Gauthier,  however,  placoa 
this  species  in  the  genus  Trypanoplasma. 


14     NATURAL  HISTORY  OF  SLEEPING  SICKNESS 

now  known  that  in  nearly  every  place  rats  are  infected 
with  this  species,  often  to  the  extent  of  50  per  cent.,  but 
it  is  not  harmful  to  them  unless  present  in  great  numbers. 
The  first  disease-producing  Trypanosome  described  was 
T.  evansi,  which  kills  numbers  of  horses,  camels,  elephants 
and  dogs  in  Asia  and  North  Africa  by  causing  a  disease 
known  as  "  Surra "  ;  it  was  discovered  in  1880.  Not 
until  1895  was  the  next  pathogenic  species  discovered, 
and  this  was  an  extremely  important  one,  the  know- 
ledge of  which  was  of  the  utmost  help  to  the  subsequent 
investigations  into   Sleeping   Sickness. 

This  species  was  named  T.  brucei,  after  Sir  David 
Bruce,  who  proved  it  to  be  the  cause  of  "  Tse-tse  fly 
disease  "  or  "  Nagana  "  in  South  Africa.^ 

In  1901  another  species  was  described  as  T.  equiperdum, 
the  cause  of  "  Dourine  "  in  stallions,  brood  mares,  and 
donkeys  in  America  and  North  Africa.  Also  in  1901 
was  discovered  T.  gambiense,  the  first  Trypanosome  to 
be  known  for  a  cause  of  disease  in  man.^ 

In  1902  T.  equinum  was  shown  to  be  the  cause  of  *'  Mai 
de  Caderas,"  a  fatal  disease  of  horses  in  Brazil  and  the 
Argentine  Republic.  Another  human  Trypanosome  was 
discovered  in  1909,'  by  Chagas  ;  it  causes  in  children, 
and  adults  who  have  not  become  immune  in  childhood, 
chronic  fever,  enlargement  of  the  thyroid  gland,  and 
puffiness  of  the  face,  and  may  rarely  result  in  death. 
This  species  was  found  to  differ  sufficiently  in  its  life- 
history  to  be  put  in  a  new  genus,  and  has  been  named 
Schizotrypanum  cruzi.  In  1910  it  was  shown  that  the 
cause  of  the  acute  Trypanosomiasis  of  Rhodesia  was 
differentiated,  not  by  its  morphology,  but  by  its  effects 

^  Preliminary  Report  on  the  Tse-tse  fly  disease  or  Nagana  in  Zulu- 
land,  1895. 

*  British  Medical  Journal,    1902,   January   4th,   p.    42. 

8  Chagas,  Brazil  Medico,  1909,  April  22nd.  See  Bull.  Inst.  Pasteur, 
1909,  May  30th,  pp.  453-4.  Also  Bulletin  of  the  Sleeping  Sickness 
Bureau,  vol.   1,  p.   252;  vol.   2,  p.    117. 


TRYPANOSOMES  15 

upon  animals,  from  its  close  allies  T.  gambiense  and  T. 
bruceiy  and  it  is  now  known  as  T.  rhodesiense.^ 

In  1913  another  species  was  found  in  man,  causing 
in  natives  of  Nigeria  a  chronic  swelling  of  the  glands  in 
the  neck  very  like  the  earliest  stages  of  Sleeping  Sickness, 
but  very  rarely  going  beyond  that  ;  it  has  been  named 
T.  7iigeriense.^ 

It  must  not  be  thought  that  every  Trypanosome  is  a 
cause  of  disease.  This  is  very  far  from  being  the  case  ; 
the  production  of  disease  is  a  mere  accident  from  the 
Trypanosome's  point  of  view,  an  occurrence  of  fatal 
import  for  itself  as  well  as  the  host  should  the  latter 
die! 

Although  only  a  few  of  the  pathogenic  species  have 
been  mentioned,  all  of  them  together  are  a  very  small 
fraction  of  the  total  number  of  Trypanosomes  and  their 
allies  that  are  known.  They  occur  in  the  blood  of  fishes, 
reptiles,  amphibia,  birds  and,mammals  ;  in  the  vital  fluids 
of  molluscs,  in  the  alimentary  canal  of  insects  and  other 
invertebrates. 

By  cultural  methods  it  has  been  found  that  normal 
English  cattle  have  Trypanosomes  in  their  blood,  and 
Bruce  first  found  that  even  the  species  that  cause  disease 
in  domestic  animals  lives  harmlessly  in  the  indigenous 
wild  animals.  Dr.  Duke  has  shown  that  the  "  Situtunga  " 
antelope  {Tragelaphus  spekei)  carries  in  its  blood  the 
deadly  Trypanosome  gambiense  without  any  harm  to  itself. 
It  must  be  remembered  that  Trypanosomes  are  not  like 
the  bacteria  such  as  that  of  anthrax,  which  form  highly 
resistent  spores,  and  by  the  death  of  their  host  and  its 
disintegration  are  disseminated  more  widely  in  a  condi- 
tion in  which  life  may  be  maintained  indefinitely. 

The  position  seems  to  be  this.    Many  insects,  for  instance 

^  Stephens  and  Fantham,  Proc.  Royal  Soc,  Series  B,  1910,  No.  561, 
pp.  28-32. 

*  J.  W.  Scott  Macfie,  Annals  of  Tropical  Medicine  and  Parasitology, 
1913,   August,  vol.   7,  No.   3a,  pp.   339-56. 


16     NATURAL  HISTORY  OF  SLEEPING  SICKNESS 

the  house  fly,  contain  in  the  alimentary  canal  Flagellates 
of  a  type  closely  allied  to  Trypanosomes,  which  live  a 
natural  parasitic  life  in  the  fly  only. 

When  the  ancestors  of  the  present  blood-suckers  became 
addicted  to  this  habit,  probably  a  development  of  the 
habit  of  feeding  on  the  fluid  exuding  from  sores,  it  may 
well  have  happened  that  some  of  these  internal  parasites 
were  inoculated  into  the  blood  of  the  animal.  Those 
that  survived  may  well  have  caused  disease  as  a  result 
of  their  vital  activities  ;  if  so,  by  the  process  of  natural 
selection,  those  which  soonest  became  adapted  to  the 
new  conditions  and  no  longer  brought  about  a  condition 
unfavourable  to  the  host,  on  whose  life  they  would  now 
depend,  would  have  most  chance  of  surviving. 

This  theory  is  supported  by  some  very  interesting 
work  done  by  Fantham  and  Porter,  who  showed  that 
Herpetomonas  jaculum,  a  normal  inhabitant  of  the  gut 
of  the  "  Water  scorpion  "  {Nepa  cinerea),  when  introduced 
into  the  peritoneal  cavity  of  mice  or  even  taken  by  them 
in  food  eventually  finds  its  way  into  the  blood  and  causes 
symptoms  like  those  of  "  Kala-azar  "  in  man,  from  which 
the  mouse  dies.^  But  if  the  mouse  had  not  died  so 
quickly  there  might  have  been  developed  such  immunity 
to  the  new  substances  circulating  in  its  blood  as  the  result 
of  the  vital  activities  of  the  Herpetomonas  that  friendly 
relations  between  the  two  would  result  and  mammal 
and  parasite  would  become"'mutually  immune  to  each 
other,  as  appears  to  be  the  case  with  wild  game  and 
T.  brucei.         ^^ 

When  man  with  his  non-immune  domestic  animals 
comes  into  relation  with  this  equilibrised  system  the 
equilibrium  is  disturbed  ;  the  Trypanosome  finds  itself 
introduced  into  the  circulation  of  hosts  to  which  it  is 
a  novelty  and  *'  disease  "  results. 

1  Fantham  and  Porter,  Proc.  Camb.  Phil  Soc,  1915,  vol.  18,  pp.  39-50, 
137-48. 


TRYPANOSOMES   AND  THEIR  HOSTS        17 

But  even  man  himself  shows  a  gradual  acquirement 
of  immunity.  In  West  Africa  Sleeping  Sickness  is  not 
generally  so  virulQnt  as  in  the  Uganda  epidemic,  and 
the  disease  has  been  known  in  that  area  for  a  very  much 
longer  time.  The  species  of  Trypanosome  known  as 
T.  nigeriense  causes  only  a  mild  form  of  disease  which 
is  very  rarely  fatal,  so  it  would  appear  to  be  the  species 
which  has  been  longest  in  contact  with  man.  On  the 
other  hand,  T.  rhodesiense  is  very  much  more  virulent  than 
any  other  human  Trypanosome  known  to  us,  and  it 
appears  to  have  arisen  as  a  sudden  "  mutation  "  from 
the  animal -inhabiting  species  T.  brucei.  It  is  only  ten 
years  since  this  undesirable  addition  to  the  list  of  "  human  " 
Trypanosomes  made  its  presence  known  to  us  by  causing 
a  disease  previously  unknown  in  that  part,  or  at  least 
unrecognized  as  distinct  from  malaria, 

Trypanosomes  are  transferred  from  one  host  to  another 
by  the  agency  of  various  invertebrates,  which  are  as 
necessary  for  its  existence  as  are  the  animals  in  whose 
blood  they  also  live. 

In  the  blood  they  only  multiply  by  fission,  asexually 
or  vegetatively  ;  but  in  the  invertebrate  host  they  go 
through  a  sexual  form  of  reproduction.  Development 
generally  commences  in  the  alimentary  canal,  whence  the 
Trypanosomes  find  their  way  into  the  "salivary  glands," 
so  that  they  are  inoculated  into  the  new  vertebrate  host 
when  the  blood-sucker  injects  the  irritating  fluid  secreted 
by  those  glands  in  order  to  produce  a  free  flow  of  blood. 
The  effect  of  this  fluid  is  familiar  to  all  who  have  been 
"  bitten  "  by  mosquitoes.  Such  an  alternation  of  sexual 
with  asexual  methods  of  reproduction  is  called  a  "cycle"  ; 
the  complicated  life  history  of  the  malaria  parasite  is  a 
more  familiar  example. 

I  think  the  fact  that  the  sexual  process  takes  place 
in  the  invertebrate  host  points  to  that  being  the  original 
host  for  the  Trypanosomes  ;  the  life  in  the  blood  is  as  it 

3 


18    NATURAL  HISTORY  OF  SLEEPING   SICKNESS 

were  an  accident,  and  many  close  allies  of  Trypanosomes 
can  do  perfectly  well  without  it. 

Trypanosomes  of  fishes  are  carried  by  leeches  ^ ;  of  birds, 
by  mosquitoes  ;  those  of  mammals  by  various  blood- 
sucking insects.  Thus,  the  rat  Trypanosome  is  trans- 
mitted by  the  rat  flea,  the  species  causing  "  Surra " 
in  animals  by  the  large  flies  often  called  "  Cleggs " 
{Tabanidce),  and  those  causing  "  Nagana "  in  animals 
and  Sleeping  Sickness  in  man  are  carried  by  Tse-tse 
flies  (Glossina). 

The  Trypanosome  of  "  Dourine  "  is  particularly  interest- 
ing, because  it  seems  to  have  found  that  it  can  do  without 
an  intermediate  insect  host,  and  is  transmitted  directly 
from  male  to  female  animal,  thus  having  severed  all 
relations  with  the  ancestral  home  ! 

It  may  be  pointed  out  that  there  is  a  close  analogy 
shown  by  Spirochaetal  diseases  of  man,  some  of  which 
are  carried  by  an  intermediate  host  while  others  are  not  ; 
the  pathology  of  the  two  classes  also  shows  much  in 
common,  which  is  not  surprising,  considering  how  closely 
allied  are  Trypanosomes  and  Spirochsetes. 

Lastly,  the  very  interesting  species  which  causes  in- 
flammation of  the  thyroid  gland  with  fever  in  Brazil,  is 
carried  by  an  insect  {Conorhinus)  of  the  order  Hemiptera 
or  "  bugs,"  an  order  which  numbers  extremely  few 
blood-suckers  among  its  ranks,  although  all  are  adapted 
for  obtaining  food  by  suction.  Darwin  made  special 
mention  of  this  bug  in  his  journal,  and  remarks  that 
"  one  feast  kept  it  fat  during  four  whole  months."  ^ 

The  Tse-tse  fUes  will  now  be  dealt  with  more  fully, 
but  in  this  chapter  I  will  only  give  a  general  account, 
reserving  a  full  account  of  the  natural  history  of  Olosaina 
palpalis  for  another  chapter. 

'  See  Miss  M.  Robertson's  paper  in  Phii.  Trans.  Royal  Soc,  1911, 
Series  B,  vol.  202,  pp.  29-50. 

*  Voyage  round  the   World,  edition   1890,  p.   316. 


TSE-TSE   FLIES  19 

Some  sixteen  species  exist,  which  are  entilrey 
Ethiopian  in  their  distribution  ;  for  though  one  species 
{tachinoides)  is  found  in  the  south-west  corner  of  Arabia, 
that  area  is  faunistically  part  of  the  Ethiopian  region. 
Tse-tse  do  not  occur  in  Africa  north  of  the  Sahara  nor 
south  of  St.  Lucia  Bay  in  Zululand.  It  is  remarkably 
interesting,  therefore,  that  fossil  flies  have  been  found 
in  Colorado  referable  to  this  group, ^  and  it  has  been 
suggested  by  Osborn  that  they  were  responsible  at  least 
in  part  for  the  extinction  of  many  of  the  large  mammals 
which  abounded  in  Cainozoic  times  and  by  their 
migrations  came  into  contact  with  blood-sucking  flies  to 
which,  and  their  associated  flagellates,  they  had  not  yet 
become  habituated. ^ 

The  first  Tse-tse  which  I  wish  to  mention  particularly 
is  Glossina  morsitans,  known  to  travellers  in  Africa  as 
"The  Fly,"  or,  collectively,  as  "Fly."  According  to 
Austen  ^  the  exact  origin  of  the  name  is  uncertain  ;  it 
is  believed  to  be  a  corruption  of  "  Nsi-Nsi,"  said  to  be 
the  name  given  to  blood-sucking  flies  by  natives  of  some 
parts  of  Africa.  A  passage  in  the  Old  Testament  *  possibly 
refers  to  Glossina,  although  it  may  also  apply  to  other 
flies  with  the  same  habits  :  "  And  it  shall  come  to  pass 
in  that  day,  that  the  Lord  shall  hiss  for  the  fly  that  is  in 
the  uttermost  part  of  the  rivers  of  Egypt,  and  they  shall 
come,  and  shall  rest  all  of  them  in  the  desolate  valleys, 
and  in  the  holes  of  the  rocks,  and  upon  all  thorns,  and 
upon  all  bushes." 

The  early  African  travellers  of  the  middle  of  the  nine- 
teenth century  were,  naturally,  much  impressed  by  the 
fly  which  was  so  well  known  to  the  natives  for  inflicting 
a  "  poisonous  bite  "  upon  their  cattle. 

*  Cockerell,  Proc.  of  the  United  States  National  Museum,  vol.  liv.  1918, 
p.  308. 

*  Letter  from  Professor  Cockerell  in  Nature,  1919,  June  5,  vol.  ciii. 
p.  265.  «  Monograph  on  the  Tse-tse  Flies,  1908,  p.  32. 

*  Isaiah,  chapter  vii.  verses  18,  19. 


20    NATURAL  HISTORY  OF  SLEEPING  SICKNESS 

Thus  Gordon  Gumming  in  1850  wrote  as  follows  :i 
"  When  under  the  mountains  on  the  south  bank  of  the 
Limpopo  river  I  met  with  this  famous  fly  whose  bite  is 
certain  death  to  oxen  and  horses.  This  fly  is  similar  to 
the  fly  in  Scotland  called  '  Kleg,'  but  a  little  smaller. 
They  are  very  quick  and  active,  and  storm  a  horse  like 
a  swarm  of  bees,  alighting  on  him  in  hundreds  and 
drinking  his  blood.  The  animal  thus  bitten  pines  away 
and  dies  at  periods  varying  from  a  week  to  three  months." 

And  again  :  "  The  next  day  one  of  my  steeds  died  of 
Tse-tse.  He  had  been  bitten  under  the  mountain  range 
lying  to  the  south  of  this  fountain.  The  head  and  body 
of  the  poor  animal  swelled  up  in  a  most  distressing 
manner  before  he  died.  His  eyes  were  so  swollen  that 
he  could  not  see,  and  in  darkness  he  neighed  for  his  com- 
rades who  stood  feeding  beside  him." 

Again,  Livingstone  in  1857  wrote  as  follows  :  ^  "  The 
peculiar  buzz  when  once  heard  can  never  be  forgotten 
by  the  traveller,  for  it  is  well  known  that  the  bite  of 
this  poisonous  insect  is  certain  death  to  ox,  horse  or  dog. 
In  this  journey  we  lost  forty-three  oxen  by  its  bite. 
We  watched  the  animals  carefully,  and  believe  that  not 
a  score  of  flies  were  ever  upon  them. 

"  A  most  remarkable  feature  is  the  perfect  harmlessness 
of  the  bite  to  man  and  wild  animals."  The  italics  are 
mine,  to  emphasize  that  the  scientific  mind  of  the  great 
explorer  had  noticed  this  pregnant  fact,  although  the  full 
significance  was  not  made  plain  until  Bruce's  work  was 
published.  **  We  never  experienced  the  slightest  injury 
from  them  ourselves,  although  we  lived  two  months  in 
their  habitat,  which  was  in  this  case  as  sharply  defined 
as  in  many  others  ;  for  the  south  bank  of  the  river  was 
infested  by  them,  and  the  north  bank,  where  our  cattle 

^  Five   Years  of  a  Huntefa  Life  in  the  Far  Interior  oj  South  Africa, 
vol.  ii.  p.  210,  etc. 

*  Missionary  Travels  and  Researches  in  South  Africa,  p.  79,  etc. 


LIVINGSTONE'S   ACCOUNT   OF  THE  TSE-TSE     21 

were  placed,  only  fifty  yards  distant,  contained  not  a 
single  specimen.  This  was  the  more  remarkable  as  we 
often  saw  natives  carrying  over  raw  meat  to  the  opposite 
bank,  with  many  Tse-tses  settled  upon  it." 

This  account  makes  clear  one  of  the  most  remarkable 
points  in  the  natural  history  of  this  species  of  Glossina, 
namely,  the  very  sharply  marked  areas  which  it  inhabits  ; 
this  must  depend  upon  the  presence  or  absence  of  certain 
factors  in  its  environment,  but  has  not  yet  been  thoroughly 
explained. 

After  noting  the  symptoms  of  "fly  disease  "  Livingstone 
continues  :  "  These  symptoms  seem  to  indicate  a  poison 
in  the  blood,  the  germ  of  which  enters  when  the  proboscis 
is  inserted  to  draw  blood.  The  poison  germ,  contained 
in  a  bulb  at  the  root  of  the  proboscis,  seems  capable,  although 
very  minute  in  quantity,  of  reproducing  itself."  The  words 
which  I  have  put  in  italics  were  written  by  Livingstone 
about  fifty  years  before  the  discovery  of  the  Trypanosome 
by  Bruce,  and  some  years  before  the  first  discovery  of 
micro-organisms  of  disease  by  Louis  Pasteur  !  ^ 

The  genus  Glossina  was  founded  in  1830,  when  Wiede- 
mann described  a  new  species  of  fly  from  Sierra  Leone, 
and  in  the  same  year  another  species  was  described  from 
the  Congo  by  Robineau-Desvoidy  :  this  is  the  one  which 
is  now  known  as  Glossina  palpalis.  It  is  interesting 
that  the  first  scientific  description  of  a  Tse-tse  was  not 
that  of  the  one  so  long  known  to  natives  in  South 
Africa  ;  this  was  not  named  until  1850,  when  Gordon 
Cumming's  travels  made  the  fly  well  known  in  England. 

Glossina  palpalis  frequents  forested  and  humid  country, 
and  is  not  found  so  far  south  as  its  more  widely  distri- 
buted relative  morsitans.  The  great  river  courses  and 
lake  shores  in  the  tropics  furnish  the  shade  and  humidity 

1  In  1857  Pasteur  first  showed  that  fermentation  was  due  to  micro- 
organisms ;  in  1865  he  showed  that  silkworm  disease  was  due  to  micro- 
organisms. In  1876  the  first  '•  bacterium  "  (of  anthrax)  was  isolated 
by  Koch. 


22      NATURAL  HISTORY  OF  SLEEPING  SICKNESS 

that  it  requires,  hence  the  Congo  basin,  the  upper  Nile, 
and  the  shores  of  Lake  Victoria  abound  with  it. 

Tse-tse  flies  are  on  the  whole  diurnal,  though  one  or  two 
species  are  known  to  bite  at  night ;  but  the  traveller  is 
safe  from  both  morsitans  and  palpalis  after  dark. 

The  life  history  of  the  Tse-tse  flies  is  very  remarkable, 
and  almost  unique  among  insects.  No  eggs  are  laid,  but 
a  single  egg  is  hatched  within  the  abdomen  of  the  mother 
fly  and  the  larva,  a  white  grub,  is  fed  by  the  secretion  of 
special  glands.  When  the  larva  is  full  grown  the  mother 
fly  seeks  a  suitable  spot  and  the  larva  is  extruded.  It  is 
a  very  active  little  creature,  and  crawls  about  seeking 
for  a  spot  where  it  can  burrow  into  the  soil.  It  is  helped 
to  do  this  by  two  curious  bosses  at  the  posterior  end  of 
the  body  which  are  of  hard  chitin  and  give  the  larva  a 
firm  purchase  when  it  begins  to  burrow.  As  soon  as 
it  has  buried  itself  its  skin  hardens  and  it  becomes  a  dark 
brown  oval  pupa  with  the  two  bosses  at  the  posterior 
end  which  were  seen  in  the  larva,  and  differ  in  shape 
according  to  the  species  of  fly. 

After  a  period  of  very  varied  duration  the  perfect  fly 
emerges  by  cracking  the  pupa-case  or  "  puparium  " 
at  one  end  and  by  means  of  an  extrusible  bladder  on 
the  front  of  its  head  works  its  way  up  through  the  soil 
covering  it  and  creeps  up  a  stem  in  a  great  hurry  to  let 
the  wings  hang  down  and  expand  before  they  have  hard- 
ened. I  have  seen  many  palpalis  thus  emerge  from  the 
ground,  and'  they  always  give  the  impression  that  it  is 
a  matter  of  the  utmost  importance  that  they  should  lose 
no  time  ! 

Let  us  now  glance  at  the  development  of  our  knowledge  of 
Tse-tse  flies  and  disease.  It  was  quite  clear  to  the  earliest 
travellers  in  South  Africa  that  *'  The  Ely,"  as  Glossina 
morsitans  was  called,  was  a  cause  of  the  fatal  disease  of 
cattle  and  horses  to  which  allusions  have  been  made. 

Sir  David  Bruce  in  1894  was  able  to  report  that  the 


NAGANA  AND   SLEEPING   SICKNESS         23 

actual  cause  of  the  disease  **  Nagana  "  was  a  Trypanosome 
which  was  named  brucei  after  its  discoverer,  and  was  taken 
up  by  a  Tse-tse  when  it  fed  on  the  blood  of  an  animal 
suffering  from  nagana.  It  was  believed  that  the  fly 
inoculated  the  Trypanosome  into  a  fresh  animal  when  it 
fed  again  in  the  same  manner  that  a  vaccinator  introduces 
the  lymph  on  the  point  of  his  lancet,  that  is  to  say,  by 
direct  inoculation.  Thus  in  the  case  of  Nagana  we 
have  started  with  the  carrier  of  the  disease  and  found 
the  germ  which  it  carried. 

When  the  problem  of  Sleeping  Sickness  became  so 
acute  in  Uganda,  the  Royal  Society  sent  out  a  Commission 
in  investigate  the  disease,  and  the  members  arrived  in 
Uganda  in  July  1902.  But  the  first  step  towards  the 
elucidation  had  already  been  made  in  West  Africa.  In 
1901  an  Englishman  in  charge  of  a  steamer  on  the  Gambia 
river  was  admitted  to  hospital  at  Bathurst  for  "  fever," 
and  Dr.  Forde  found  in  his  blood  peculiar  organisms 
whose  nature  was  unknown  to  him.  The  patient  was 
sent  to  Liverpool,  and  Dr.  Dutton  recognized  the  new 
organism  to  be  a  Trypanosome  :  the  patient  eventually 
died  at  the  commencement  of  1903. 

In  1902  Drs.  Dutton  and  Todd  found  Trypanosomes 
in  the  blood  of  several  West  African  negroes  suffering 
from  the  early  stages  of  what  we  now  know  to  be  Sleeping 
Sickness,  but  in  those  days  the  condition  had  not  been 
recognized  as  connected  with  that  well  known  disease. 
This  early  stage  of  fever  now  came  to  be  known  as 
"  Trypanosome  fever,"  or  "  Trypanosomiasis,"  and  in 
March  1903  Dr.  Baker  found  the  Trypanosome  in  a 
case  in  Uganda,  ^  though  he  did  not  recognize  the  full 
importance  of  this  fact.  The  next  development  was  the 
finding  by  Dr.  Castellani  of  Trypanosomes  in  the  cerebro- 
spinal fluid  of  a  case  of  Sleeping  Sickness  in  April  1903,^ 

»  British  Medical  Journal,  1903,  May  30th,  p.  1254. 
*  Proc.   Roy.   Soc,    1903,   vol.   Ixxi.   pp.   501-8. 


24    NATURAL  HISTORY  OF  SLEEPING  SICKNESS 

and  afterwards  by  Bruce  and  Nabarro  in  every  case  of 
Sleeping  Sickness  examined.  Thus  was  made  clear  the 
fact  that  *'  Trypanosome  fever  "  is  the  early  stage  of 
the  fatal  disease,  and  the  next  step  was  to  find  out  how 
the  disease  was  transmitted. 

At  this  step  a  comparison  of  what  was  known  about 
Nagana  with  what  has  been  found  out  about  Trypano- 
somiasis aids  in  the  understanding  of  further  developments. 
In  the  former  case  investigation  commenced  with  strong 
presumptive  evidence  that  a  Tse-tse  fly  was  the  agent 
through  which  the  disease  was  acquired  ;  in  the  latter 
case  the  germ  was  discovered  and  it  became  necessary 
to  ascertain  how  it  was  transmitted.  Since  Nagana  had 
been  proved  to  be  due  to  a  Trypanosome  carried  by  the 
blood-sucking  fly  Glossina  morsitans,  and  Sleeping  Sickness 
had  now  been  shown  to  be  due  to  another  species  of 
Trypanosome,  evidence  pointed  to  a  blood-sucking  fly 
as  the  carrier  of  this  new  species  Trypanosoma  gambiense, 
and  requests  were  made  to  officials  in  the  Sleeping  Sick- 
ness area.s  fo  send  specimens  of  all  biting  flies  in  the 
neighbourhood  to  the  laboratory  in  Entebbe.  It  very 
soon  became  clear  that  one  fly  was  found  throughout 
the  areas  being  ravaged  by  the  disease,  that  is  the  shaded 
margins  of  the  great  lakes  and  rivers  ;  this  fly  was 
Glossina  palpalis.  Accordingly  experiments  were  made 
to  test  whether  the  fly  can  be  the  carrier,  and  specimens 
captured  on  the  shores  of  the  lake  were  fed  upon  monkeys 
whose  blood  was  examined  daily,  the  procedure  being 
the  same  as  in  Bruce's  classical  work  on  Nagana.  Con- 
clusive proof  was  obtained  when  the  Trypanosome  was 
found  in  the  blood  of  the  monkeys,  and  the  discovery 
was  announced  by  the  Commission  in  1903.^  Further 
proof  was  obtained  by  feeding  bred  flies  on  monkeys 
which  had  been  already  infected  by  wild  flies,  and  then 
making  them  feed  upon  another  monkey  ;  the  second 
^  Reports  of  the  Sleeping  Sickness  Commission,  No.  IV,  pp.   5G-65. 


FLY    BEACH    ON    DAMBA    ISLE. 

A  favourite  breeding  ground  is  under  tlie  bushes  at  the  gap  on  the  right. 

^V  f'er)iiissioit  of  the  Royal  Society  and  the  Controller,  H.M.  Stationery  Ofice. 


'^r^^ 
<^,~  yW' 


FLY    BEACH    ON    BUGALLA    ISLE. 
By  permission  of  the  Royal  Society  and  the  Controller,  H.M.  Stationery  Office. 


To  face  p.  J4. 


LIFE  CYCLE  OF  TRYPANOSOMES 


25 


monkey  in  a  proportion  of  cases  also  showed  the  Trypano- 
some  in  its  blood.  Control  experiments  showed  that  a 
freshly  hatched  fly  contains  no  Trypanosomes,  so  that 
those  in  the  above  experiments  must  have  acquired  them 
from  the  first  monkeys  fed  upon. 

The  two   diseases   Nagana   and   Sleeping   Sickness   are 
thus  entirely  parallel,  as  is  shown  by  the  following  table  : 


Diseaso. 

Subject.                  Cause. 

Natural  Host. 

Carrier. 

Nagana 

Sleeping 
Sickness 

Domestic 
animals 

Man 

Trypanosoma 
brucei 

Trypanosoma 
gamhiense 

Big  Game 

The  antelope 

Tragelaphus 

S2iekei 

Glossina 
morsitans 

Glossina 
palpalis 

It  has  been  said  that  the  transmission  of  the  Trypano- 
some  of  Nagana  was  believed  to  be  entirely  mechanical, 
and  for  some  years  this  was  also  thought  to  be  the  case 
with  T.  gambiense.  With  further  knowledge,  however, 
it  became  clear  that  there  was  a  period  after  the  fly 
had  fed  during  which  the  Trypanosome  could  not  be 
transmitted  to  a  fresh  animal.  It  had  previously  been 
supposed  that  this  was  because  the  Trypanosome  was  no 
longer  alive  in  the  fly,  but  KJeine,  working  in  German 
East  Africa,  showed  in  1908  that  the  non-infectivity  of 
the  fly  after  a  few  days  did  not  mean  the  death  of  the 
Trypanosome,  but  that  it  was  going  through  a  cycle  of 
development  in  the  alimentary  canal  of  the  fly,  and  was 
not  in  an  infective  condition.  For  when  the  develop- 
ment was  complete  Kleine  found  that  the  fly  could 
convey  the  disease  fifty  days  after  it  had  acquired  the 
Trypanosome.  These  most  important  results  were  fully 
confirmed  in  Uganda  in  1909  ^  and  it  was  found  that  the 
time  required  for  the  cycle  of  development  in   tha  fly 

*  Reports  of  the  Sleeping  Sickness  Commission,  vol.  x,  p.  46,  etc.  ; 
vol.  xi.  p.  12,  etc. 


26    NATURAL  HISTORY  OF  SLEEPING  SICKNESS 

varied,  from  eighteen  to  forty-five  days,  after  which 
time  a  fly  will  remain  infective  and  able  to  introduce 
the  Trypanosome  into  every  animal  it  bites  for  as  long 
as  seventy-five  days  ! 

The  complete  life  cycle  of  the  Trypanosome  in  the  fly 
was  worked  out  fully  in  Uganda  by  Miss  Robertson 
in  1913.^  The  Trypanosome  multiplies  in  the  gut  of  the 
fly,  but  the  forms  of  m^ultiplication  are  not  those  which 
will  live  in  the  blood  stream  of  the  vertebrate  host,  and 
a  somewhat  different  form  is  developed  which  finds  its 
way  into  the  "  salivary  "  glands  of  the  fly  and  is 
injected  with  the  irritant  secretion  of  the  gland  which 
presumably  is  intended  to  produce  a  free  flow  of  blood 
in  the  site  of  puncture.  We  have  now  arrived  at  the 
most  important  fact  that  when  once  it  has  acquired 
the  Trypanosome  the  Tse-tse  fly  can  infect  for  the  rest 
of  its  life. 

We  must  now  consider  the  relations  between  Tse-tse, 
Trypanosome,  and  the  "  alternative  hosts  "  of  the  latter 
from  which  the  fly  acquires  it. 

It  was  known  from  Bruce 's  researches  on  Nagana  ^ 
that  Trypanosoma  brucei  is  a  natural  and  harmless  inhabi- 
tant of  the  blood  of  various  species  of  big  game  in  the 
"  fly  areas,"  and  as  soon  as  Sleeping  Sickness  was 
proved  to  be  due  to  another  Trypanosome,  efforts  were 
made  to  discover  its  natural  host  or  reservoir.  The 
Commission  in  Uganda  made  a  series  of  experiments 
with  the  blood  of  such  animals  and  birds  that,  inhabiting 
the  lake  shore,  might  be  justly  suspected  of  harbouring 
the  trypanosome,  but  with  negative  results.  One  impor- 
tant species  of  antelope,  however,  was  not  at  this  time 
(1908-10)  examined.  The  next  step  was  to  mfect  captive 
antelope  and  native   cattle    by  feeding  upon  them  flies 

^  Reports  of  the  Sleeping  Sickness  Commission,  No.  XIII,  p.  119,  etc. 
-  ApjDendix   to   Further  Report  on   Tse-tse   Fly  Disease  or  Nuga7ia  in 
Zululand,    1903,  p.   8.     London,   Harrison  &   Sons. 


RESERVOIRS   OF  TRYPANOSOMES  27 

caught  in  the  Sleeping  Sickness  area,  and  it  was  found 
that  this  could  be  readily  done  ;  waterbuck,  bushbuck 
and  reedbuck  in  captivity  could  all  be  made  reservoirs 
of  the  Trypanosome  without  any  harm  to  themselves, 
and  could  continue  to  infect  bred  flies  fed  upon  them  for 
more  than  twelve  months  after  they  had  been  artificially 
infected.'^  Finally,  in  March  1912,  Dr.  Duke  announced 
that  the  antelope  known  to  the  natives  as  "  Enjobe  " 
was  a  natural  reservoir  of  Trypanosoma  gambiense,  and 
the  chain  was  thus  completed. ^ 

It  had  seemed  for  some  time  probable  that  there  must 
be  a  natural  host,  although  it  had  not  been  found.  Four 
years  and  a  half  after  the  natives  had  been  removed  from 
the  islands  the  fly  there  was  still  infective,  and  it  was 
impossible  to  suppose,  that  the  same  flies  were  still  alive 
that  had  been  the  cause  of  the  epidemic.  With  one 
exception  the  animals  and  birds  and  reptiles  within 
reach  of  the  fly  had  been  sufficiently  examined  to  make 
it  almost  certain  that  they  were  not  incriminated,  and 
the  one  large  antelope  living  on  the  islands  was  yet  to  be 
excluded.  Accordingly,  in  the  latter  part  of  1911  Dr. 
Duke  came  over  to  my  camp  on  Damba  Island  to  shoot 
and  investigate  the  very  abundant  "  Enjobe "  there. 
This  antelope,  the  Situtunga  {Tragelaphus  speJcei),  lives  in 
most  intimate  association  with  the  fly  among  the  shaded 
forests  at  the  water  side. 

A  number  were  shot  and  their  blood  was  injected 
into  monkeys,  one  of  which,  injected  on  November  5th 
and  6th,  showed  Trypanosomes  in  its  blood  on  the  18th. 
It  was  taken  to  the  laboratory  on  the  mainland  and  the 
nature  of  the  Trypanosome  investigated  in  every  possible 
way,  and  Dr.  Duke  considered  that  there  was  no  doubt 
that  he  had  at  last  found  the  source  from   which  the 


*  Reports  of   the  Sleeping  Sickness  Commission,  No.  XI,  p.  71,  etc. 
^  Ibid.   No.   XII,  p.    117  et  seq.     See  also  article  by  Duke  in  BiHtish 
Medical  Journal,  1914,  February  7th. 


28    NATURAL  HISTORY  OF  SLEEPING  SICKNESS 

flies  on  the  island  acquired  the  cause  of  Sleeping 
Sickness. 

This  discovery  made  the  question  of  the  return  of  the 
natives  to  the  lake  shore  a  far  more  difficult  one  than 
was  anticipated  when  they  were  removed  during  the 
height  of  the  epidemic.  It  was  then  thought  that  as  the 
fly  was  merely  a  mechanical  carrier  of  the  Trypanosome, 
an  interval  during  which  all  known  sources  of  infection 
(the  natives)  were  kept  away  from  the  fly  would  allow 
the  disease  to  die  out,  and  when  the  life  of  the  infected 
flies  had  come  to  an  end,  the  natives  who  were  free  from 
Trypanosomes  could  return  without  danger.  But  now 
that  it  is  known  that  there  is  a  "  vicious  circle,"  the 
fly  acquiring  the  Trypanosome  from  the  antelope  and 
in  turn  inoculating  it  into  fresh  animals,  the  islands  and 
mainland  shore  of  the  lake  are  still  dangerous.  It  is 
true  that  some  consider  that  it  is  possible  that  the 
Trypanosome  has  been  for  so  long  away  from  man's 
blood  that  it  may  no  longer  be  pathogenic  to  him, 
but  against  this  is  the  fact  that  as  a  result  of  living  on 
the  islands  with  me  in  1911-12  three  of  my  native 
employees  were  found  to  be  infected  when  I  examined 
them  before  returning  to  the  islands  in  1914,  and  one  at 
least  is  reported  to  have  died. 

So  far  as  we  know  at  present,  the  fly  would  be  harmless 
without  the  antelope  and  the  antelope  without  the  fly, 
and  to  eliminate  the  disease  from  the  most  fertile  and 
beautiful  part  of  Uganda  these  two  must  be  kept  apart ; 
that  is  to  say,  one  of  them  must  be  exterminated. 

In  1914  I  obtained  most  interesting  confirmation  of 
Dr.  Duke's  results.  The  Island  of  Nsadzi,  lying  opposite 
to  Entebbe  and  south  of  it,  was  well  populated  in  the  old 
days,  and  there  was  very  little  refuge  for  Enjobe  there  ; 
I  was  told  by  my  canoe-men  that  the  antelope  was  not 
to  be  found  on  the  island  in  those  days.  In  1911  the 
flies  on  Nsadzi  were  tested  and  were  found  to  be  free 


THE  SITUTUNGA  AND  SLEEPING  SICKNESS   29 

from  infection,  for  as  many  as  5,765  failed  to  cause  infec- 
tion in  a  monkey.  In  1914,  however,  I  frequently  saw 
footprints  of  Enjobe  on  the  island,  which  had  presumably 
swum  across  the  narrow  channel  between  Nsadzi  and  the 
large  isle  Kome  to  the  east  where  Enjobe  abound.  The 
flies  were  again  tested  and  found  to  be  infected,  for  after 
2,076  had  fed  upon  a  monkey  it  showed  the  Trypanosome 
in  its  blood.  ^  Less  than  half  the  number  of  flies  that 
did  not  produce  an  infection  in  1911  produced  an  infec- 
tion in  1914,  and  this  is  associated  with  the  arrival  of 
the  buck  in  the  continued  absence  of  the  population. 

It  seems  hardly  possible  to  entertain  the  idea  of  de- 
stroying the  Enjobe,  since  when  hard  pressed  it  takes 
refuge  in  dense  papyrus  swamps,  and  even  if  it  could  once 
be  eliminated  from  the  islands  would  soon  find  its  way 
back  by  swimming  from  the  mainland,  and  would  resume 
its  former  relations  with  the  native.  Is  it,  then,  possible 
to  eliminate  the  fly  ? 

On  this  question  I  shall  have  something  to  say  in 
the  chapter  devoted  to  the  natural  history  of  Glossina 
palpalis. 

^  Reports  of  the  Sleeping  Sickness  Commission,  No.  xvii,  1919,  p.  71-74. 


CHAPTER  III 

THE    NATURAL    HISTORY    OF    GLOSSINA 
PALPALIS 

This  species  is  pre-eminently  a  frequenter  of  the  shady 
forests  on  the  shore  of  the  lake,  where  it  may  be  found 
in  great  abundance. 

The  method  of  estimating  its  numbers  is  to  set  trained 
natives  to  catch  the  flies  with  small  nets  from  o£E  the 
herbage  or  rocks  on  which  they  alight,  or  from  their 
own  clothing  when  the  flies  come  to  feed.  At  the  end  of 
half  an  hour  the  boys  are  whistled  in  and  the  catch 
counted,  but,  for  reasons  which  will  be  given  later, 
only  the  males  are  used.  An  average  figure  is  obtained 
representing  the  number  caught  per  boy  per  hour, 
commonly  alluded  to  as  the  "  male-boy-hour "  figure, 
by  means  of  which  one  locality  can  be  compared  with 
another.  The  highest  figure  I  have  yet  recorded  was 
obtained  in  1919  on  the  north  coast  of  the  west  of  Kome 
Isle  :  four  boys  working  for  half  an  hour  obtained  the 
average  of  125  male  flies  per  boy  per  hour.  If  it  be 
considered  that  each  fly  is  caught  in  a  net,  from  which 
it  has  to  be  taken  out  by  hand  and  put  into  a  bottle, 
and  that  besides  the  males  there  were  at  least  a  quarter 
as  many  females  caught  at  the  same  time,  it  must  be 
admitted  that  the  fly  can  be  very  plentiful  ! 

One  of  the  first  things  to  be  realized  is  that  the  number 
of  flies  at  a  locality  has  little  relation  to  the  frequency 
with   which   one  is   bitten,   and  therefore  an  impression 

30 


ON    DAMBA    ISLE. 
Not  a  good  fly  shore,  as  it  was  too  marshy  for  a  breeding  ground. 


A    1  l.V    l;uV    (JAKOBO)    Ai     WUKR. 

The  white  net  in  his  right  hand  scarcely  shows  against  his  white  clothes.     He  was  found  to 
be  infected  with  T.  Hambiense  in  1914. 

To  face  p.  30. 


wmmmt^mmi^-,Ti, 


PROPORTION   OF  SEXES 


81 


derived  from  a  large  number  of  bites  gives  a  very  erroneous 
estimate.  This  fact  has  arisen  from  Fiske's  investigations 
into  the  reasons  for  the  very  varying  proportions  of  the 
sexes  at  different  localities. 

It  has  been  found  that  the  females  are  much  less  inquisi- 
tive than  the  males,  and  do  not  come  to  man  in  any  great 
numbers  unless  wishing  to  feed,  whereas  the  male  roams 
about  and  investigates  any  new  object  without  necessarily 
being  hungry.  The  percentage  of  females  is  therefore 
an  indication  of  the  hunger  of  the  flies.  If,  however, 
a  prolonged  catch  is  made  in  one  spot,  the  percentage  of 
females  rises,  because  the  more  inquisitive  males  are 
first  caught ;  the  number  of  females  per  boy  per  hour, 
however,  remains  fairly  constant,  since  only  the  hungry 
individuals  are  taken. 

An  experiment  such  as  the  following  illustrates  this 
point  clearly.  Flies  were  caught  continuously  at  one 
point  on  the  small  island  of  Tavu  on  January  13-16,  1914, 
from  early  morning  until  the  afternoon,  and  it  is  clear 
that  the  number  of  males  was  soon  affected,  while  the 
catch  of  females  remained  constant.  The  percentage  of 
females,  however,  rose,  owing  to  the  males  being  caught 
ofi  ;  not  in  this  case  because  there  were  more  females 
eager  to  feed. 


Date. 

Time. 

Total 
Catch. 

Males  per 
Boy-Hour. 

Females 
per  Boy- 
Hour. 

Percentage 

of 

Females. 

Jan.  15,   1914 

7.45-8.45 

473 

62.5 

7.5 

10.7 

»»            >• 

9-10 

303 

36. 7 

4.3 

10.5 

»»            >» 

10.15-11.15 

235 

23.5 

6.5 

21.7 

J»                        M 

11.30-12.30 

216 

20.3 

6.8 

25.0 

>>                         >» 

1.30-2.30 

222 

20.3 

7.5 

27.0 

Jan.  16,   1914 

7.4.5-8.45 

275 

33.0 

5.7 

14.7 

>>            >> 

1.25-2.25 

241 

21.0 

11.4 

35.2 

>>            >> 

2.45-3.45 

128 

9.8 

7.1 

42.0 

The  relation  between  the  percentage  of  female  flies  in  a 


32    NATURAL  HISTORY  OF  GLOSSINA  PALPALIS 

catch  and  the  hunger  of  the  flies  was  borne  out  by  the 
behaviour  of  flies  on  different  islands  visited  by  Fiske 
and  myself  in  1914.  (See  Chapter  VI.)  Certain  islands, 
notably  Kimmi  and  Yempata,  were  remarkable  for  the 
avidity  with  which  the  flies  bit ;  on  Kimmi  they  even 
flew  out  to  the  canoe  before  it  reached  the  shore.  On 
both  these  isles  the  percentage  of  females  was  higher 
than  usual ;  on  Kimmi  it  averaged  53  per  cent.,  on 
Yempata  37  per  cent. 

The  curiosity  and  spirit  of  investigation  of  the  male 
fly  was  shown  by  a  little  experiment  on  Tavu  Island. 
I  noted  that  during  the  passage  through  some  thick 
Kinsambwe  bushes  many  leaves  became  reversed  so 
as  to  show  the  silvery  under  surface.  Male  Tse-tse 
often  settled  on  them  as  if  attracted  by  the  novelty. 
I  therefore  spent  some  time  catching  every  fly  that  settled 
on  my  white  net,  held  out  conspicuously,  and  in  one  hour 
thus  caught  twenty-six  males,  but  only  six  females. 
I  then  caught  from  off  my  clothes  those  flies  that  had 
settled  and  lowered  the  proboscis  intending  to  feed ; 
there  were  ten  females  to  eight  males.  Male  flies  may 
very  often  be  seen  which  seem  to  have  no  desire  to  feed, 
but  merely  to  rest  in  a  conspicuous  position,  often  on  a 
rock  hot  with  the  sun  ;  possibly  they  are  on  the  watch 
for  females.  There  can  be  no  doubt  that  they  use  their 
eyes  in  the  search  for  food  :  it  has  long  been  known  in 
the  case  of  G.  morsitans  that  a  man  on  horseback  or  cycle 
moving  will  attract  flies  where  none  have  been  noticed 
while  he  was  stationary.  Palpalis  would  often  alight  on 
the  canoe  drawn  up  on  the  beach  ;  presumably  the  large 
black  object  was  thought  at  first  to  be  a  hippopotamus  ! 

The  fact  that  the  fly  will  often  sit  on  a  rock  hot  with 
the  sun  is  of  interest,  seeing  that  they  are  apparently 
dependent  upon  shade,  and  are  susceptible  to  variations 
in  the  humidity  of  the  atmosphere.  I  am  convinced, 
however,  that  so  long  as  palpalis  has  a  shady  base  it  will 


ROAMING   OF  THE  FLY 


88 


make  long  excursions  from  it,  perhaps  in  search  of  food 
or  breeding  places,  and  may  be  found  in  places  where 
there  is  practically  no  shade  and  where  it  could  not  abide 
permanently.  Thus,  the  western  end  of  Nsadzi  Island 
consists  of  a  high  treeless  grassy  plateau  sloping  down 
steeply  to  a  rocky  shore  along  which  is  a  scanty  fringe 
of  sparse  bushes  throwing  very  little  shade  over  the  bare 
rocks.  Yet  if  one  descends  to  the  shore  fly  is  met  with, 
and  one  is  immediately  investigated. 

An  experiment  was  made  to  test  whether  the  fly  does 
roam  along  this  kind  of  coast.  At  one  point  there  was 
a  small  copse  about  thirty  yards  square,  furnishing  ample 
shade  to  provide  a  base  for  the  fly,  and  ten  fly  boys  were 
set  to  catch  flies  continuously  here  on  June  10,  1914. 


Time. 

Number  of  Flies 
Caught. 

Males  pet 
Boy-Hour. 

Femalea 

per 
Boy-Hour. 

Percentage 

Male. 

Female. 

9-45-1115 

11-20-11-50 

12       -12-30 

12-30-1 

1-10-1-401 

1-45-2- 15 

2-15-2-45 

51 
16 
12 
16 

17 
9 

18 

24 

15 

6 

24 

17 

3-4 
3-2 
2-4 
3-2 

3-4 
1-8 

1-2 
4-8 
3 
1-2 

4-8 
3-4 

26 
60 

65-5 
27 

58-5 
65 

121 

104 

— 

— 

— 

The  fact  that  the  number  of  males  caught  per  boy  per 
hour  was  almost  unaltered  until  the  end  shows  that  the 
121  flies  could  not  have  been  in  the  copse  at  the  com- 
mencement, but  that  a  continual  influx  occurred.  Had 
the  flies  all  been  there  at  first  ten  boys  would  soon  have 
diminished  the  number.  Also,  after  an  interval  spent 
in  looking  for  pupae  there  was  a  decided  increase  in  the 
total  number  of  flies  caught. 

1  One  empty  puparium  found. 

4 


34    NATURAL  HISTORY  OF  GLOSSINA  PALPALIS 

It  is  of  some  importance,  for  reasons  that  will  appear 
later,  to  know  whether  palpalis  does  roam  out  of  the 
shade.  There  is  no  proof  whatever  that  it  wiU  ever  cross 
the  open  water  from  one  island  to  another.  The  little 
islet  Sanga,  ofi  the  east  end  of  Kome,  has  everything  that 
the  fly  can  want,  but  for  some  reason  it  is  unable  to 
establish  itself  there,  and  none  can  be  found.  Yet  the 
adjacent  shores  of  the  larger  Kome  abound  with  fly,  and 
it  could  very  easily  find  its  way  across  the  few  hundred 
yards  of  water  to  Sanga,  yet  it  does  not. 

Palpalis,  like  morsitans,  is  at  times  a  great  nuisance, 
for  it  will  quietly  sit  on  men's  backs  and  thus  be  carried 
a  long  way.  Indeed,  I  have  sometimes  unwittingly  taken 
them  back  to  my  tent,  where  they  remained,  and  rudely 
bit  me  while  having  a  bath  !  On  certain  days,  when  it 
is  somewhat  overcast  but  the  sun  shines  through  thin 
clouds,  they  are  perhaps  at  their  worst,  and  are  very 
eager  to  bite,  and  will  cling  to  one  for  long  distances.  A 
very  favourite  trick  is  to  alight  on  the  under  side  of  the 
brim  of  one's  hat  and  to  quietly  sidle  round  until  the  first 
piece  of  skin  free  from  hair  is  met  with,  when  the  proboscis 
is  lowered  from  its  sheath  and  a  sharp  prick  is  felt  on  one's 
temple.  It  is  a  curious  fact  that  sometimes  one  is  quite 
unaware  of  being  bitten,  and  may  suddenly  hear  the 
unmistakable  heavy  buzz  of  a  bloated  fly  leaving  after 
a  heavy  feed  ;  at  other  times  the  prick  is  felt  so  sharply 
that  it  might  be  produced  by  a  needle.  Presumably  the 
difference  depends  upon  whether  the  fine  point  of  the 
proboscis  finds  a  nerve  end  or  not  ! 

When  a  fly  alights  to  feed  it  sidles  about  over  the 
skin  and  appears  to  be  feeling  for  a  soft  place  :  when  it 
is  satisfied  the  legs  are  slightly  straddled  out,  and  the 
proboscis  lowered  from  its  sheath  into  a  vertical  position, 
after  which  it  gradually  penetrates  up  to  the  bulb  at  its 
base.  It  is  then  withdrawn  slightly  and  the  body  of  the 
fly  begins  to  swell  with  red  blood.     Almost  at  once  the 


FOOD  OF  THE  FLY  85 

excess  of  fluid  is  exuded  as  a  bead  at  the  posterior  end  of 
the  body,  so  that  the  fly  is  enabled  as  it  were  to  have  a 
larger  feed  of  corpuscles  than  if  it  were  compelled  to  retain 
all  the  fluid  part.  After  a  full  feed  the  abdomen  becomes 
as  large  as  a  ripe  red-currant,  and  the  red  blood  shows 
through  the  distended  skin ;  the  gorged  insect  flies  heavily 
away  to  a  neighbouring  leaf  and  rests  awhile  to  digest 
the  meal  ! 

On  clear  hot  days,  when  a  strong  wind  may  be  blowing, 
palpalis  is  not  so  eager  to  bite  ;  nor  on  any  day  during 
the  hottest  hours.  But  about  4  p.m.  it  is  always  ready 
again,  and  I  have  been  bitten  quite  in  the  dusk  of  the 
late  afternoon  :  at  night,  however,  it  is  harmless,  nor 
does  it  come  to  light  as  the  big  East  African  species 
brevipalpis  is  known  to  do.  This  habit  of  biting  again 
more  freely  in  the  evening  is  of  interest,  for  it  is  at  this 
time  that  the  Situtunga  antelope,  which  is  a  source  of 
food,  comes  out  from  the  dense  forests  and  wanders 
along  the  edge  browsing  on  the  bushes,  where  it  meets 
palpalis. 

The  question  of  the  food  of  Tse-tse  flies  is  of  the  highest 
importance,  and  was  one  of  those  set  me  by  the  Tropical 
Diseases  Committee  of  the  Royal  Society  when  I  first 
went  out  in  1910.  In  the  case  of  morsitans  certain  ob- 
servers, notably  the  late  F.  C.  Selous,  held  that  the  blood 
of  buffaloes  was  essential  to  it,  and  that  it  died  out  or 
migrated  if  none  was  available.  Few  observations  had 
been  made  on  Glossina  in  a  state  of  nature,  but  from 
an  examination  of  the  blood  taken  from  the  stomachs 
of  wild  flies  the  Commission  in  Uganda  in  1910  ^  had 
deduced  that  "  the  blood  in  the  majority  of  the  flies  had 
been  obtained  from  birds  or  reptiles,  and  of  these  the 
reptilian  blood  was  twice  as  frequent  as  the  blood  of  birds." 

It  must  however  be  confessed  that  the  method  employed 

^  Report    XI    of    the    Sleeping    Sickness  Commission,    1911,   p.    112, 
etc. 


36  NATURAL  HISTORY  OF  GLOSSINA   PALPALIS 

of  distinguishing  between  avian  and  reptilian  blood  was 
crude  and  open  to  a  wide  margin  of  error, 

I  repeated  this  work  with  a  greater  number  of  flies  and 
at  greater  length,  and  using  as  standards  such  sources 
of  food  as  the  flies  might  meet  with,  viz.  cormorant,  croco- 
dile, Varanus,  python,  frog  and  lizard. 

At  Jinja  I  had  found  that  the  proportion  of  mammalian 
to  non-mammalian  blood  in  over  12,000  wild  flies  was 
indicated  by 

M  :  N  ::  31-5  :  68-5. 

On  Damba  Island  the  proportions  in  over  6,000  flies  were 

M  :  N  :  :  21  :  79. 

Now  in  both  these  places  antelope's  blood  was  readily 
obtainable,  for  Situtunga  abounded  on  Damba  and  bush- 
buck  were  constantly  seen  in  the  fly  area  at  Jinja  ;  hippo- 
potami were  of  course  available  at  both  localities.  In 
1914  further  work  was  done  and  blood  was  examined 
from  flies  taken  on  islands  where  there  were  no  Situtunga, 
and  others  such  as  Kome,  where  Situtunga  abounded. 

In  flies  from  five  small  islands  not  inhabited  by  Situ- 
tunga the  proportions  of  mammalian  to  non-mammalian 
blood  were  : 

M  :  N  :  :  4  :  96. 

On  two  isles  inhabited  by  the  buck  the  figures  were  : 

M  :  N  :  :  25  :  75. 

Now  on  all  islands  hippopotamus  blood  is  obtainable  ; 
indeed,  on  those  of  the  first  group  it  was  the  only  possible 
mammalian  blood,  and  accounts  for  the  4  per  cent,  of 
cases. 

But  even  where  Situtunga  are  present  only  about  one 
quarter  of  the  food  is  obtained  from  them,  and  it  appears 
that  Glossina  palpalis  much  prefers  non-mammalian 
blood. 


ANIMALS   FED   UPON 


37 


The  question  then  arises,  does  this  come  from  birds 
or  reptiles  ?  In  1911-12  careful  measurements  were 
made  in  forty-six  cases,  that  is,  from  blood  taken  from 
flies  that  had  fed  recently  enough  to  allow  the  corpuscles 
to  be  measured  unaltered  by  digestion. 

In  each  case  fifty  corpuscles  were  traced  with  the  camera 
lucida,  and  the  average  measurements  obtained  for  com- 
parison with  known  types.  Although  in  some  cases  a 
given  specimen  was  with  difficulty  allotted  to  any  one 
type,  the  following  result  was  arrived  at : 


Source.              Percentage. 

Actual 
Number. 

Source. 

Percentage. 

Actual 
Number. 

Avian 
Reptilian 

4-3 
95-7 

V 

4^^ 

Lizards 

Crocodile 

Tortoise 

56-8 

40-9 

2-3 

25 

18 

1 

—                    100                  46 

i 

— 

100           \       44 

j 

In  two  cases  birds  appear  to  have  been  the  source.  These 
would  in  all  probability  have  been  cormorants  or  darters, 
which  so  often  sit  on  a  branch  at  the  edge  of  the  water 
with  the  wings  spread  open  ;  but  the  herons  and  ibis  which 
frequent  the  shore  may  also  be  bitten. 

Nearly  57  per  cent,  of  the  blood  derived  from  reptiles 
seems  to  have  come  from  lizards,  probably  entirely  from 
the  great  monitor  or  Varanus,  but  measurements  of  the 
corpuscles  from  it  and  one  of  the  common  small  brown 
lizards  did  not  allow  any  distinction  to  be  drawn. 

There  is  no  possible  doubt  that  Varanus  is  a  most 
important  source  of  food.  I  have  several  times  seen  one 
slowly  sculling  along  the  surface  of  the  water  near  the 
shore,  with  the  top  of  its  head  black  with  Glossina  which 
were  evidently  so  troublesome  that  at  intervals  the 
reptile   submerged   its    head   beneath   the   surface,    only 


38    NATURAL  HISTORY  OF  GLOSSINA  PALPALIS 

to  be  reattacked  the  moment  its  head  was  raised.  On 
one  occasion  when  sitting  on  the  beach  of  Damba  I  saw 
a  Varanus  come  out  from  the  forest  and  walk  slowly 
past  me.  Tse-tse  were  around  me  in  considerable  num- 
bers, but  the  Varanus  was  evidently  equally  attractive,  for 
several  went  to  it  and  began  to  feed,  as  was  evidenced 
by  the  repeated  movements  it  made  to  scratch  them  off 
with  its  hind  legs. 

Crocodiles  are  also  an  extremely  important  source  of 
food,  and  their  habits  favour  this,  for  like  Varanus  they 
often  lie  for  long  periods  at  the  water's  edge.  Measurements 
of  the  blood  corpuscles  in  wild  flies  seemed  to  indicate 
that  nearly  41  per  cent,  of  the  reptilian  blood  is  from 
this  source.  It  appears  at  first  sight  rather  remarkable 
that  the  horny  plates  should  prove  no  impediment  to 
the  proboscis  of  the  fly  ;  yet  Fiske  and  I  on  Kimmi  in 
1914  watched  closely  for  half  an  hour  a  small  crocodile 
which  the  natives  had  caught  and  was  tethered  near  the 
water,  and  between  8-35-9-45  a.m.  forty  flies  had  fed 
fully  !  This  figure  did  not  include  those  that  were 
disturbed  and  did  not  feed  to  repletion. 

The  sites  chosen  by  the  fly  were  carefully  noted  in  each 
case  save  two,  and  are  indicated  below  : 


Eyelid 

.      12 

Hind  leg    . . 

9 

Neck 

6 

Flank 

2 

Fore  leg     . . 

2 

Nose 

2 

Shoulder    .  . 

Nostril 

Angle  of  mouth    . 

Hind  foot  .  . 

Back 

38 


It  is  seen  that  the  fly  was  even  able  to  penetrate  through 
the  back  ! 


ANIMALS   FED   UPON  39 

On  Ngamba  Isle  I  was  able  to  see  two  flies  upon  a  large 
crocodile  that  was  resting  among  the  bushes  and  had 
not  run  away  at  my  approach  ;  one  of  them  had  certainly 
fed. 

In  a  single  case  out  of  the  forty-four  in  which  the 
blood  in  wild  flies  was  recognizable  the  corpuscles  agreed 
well  with  those  of  a  tortoise.  Glossina  seems  to  recog- 
nize even  this  as  a  source  of  food,  for  I  saw  a  tortoise 
one  day  with  a  fly  on  its  back  making  vigorous  attempts 
to  find  a  way  for  its  proboscis  through  the  shell.  But 
though  a  crocodile's  plates  are  not  insuperable,  I  fancy 
that  the  carapace  of  a  tortoise  is  proof,  and  the  fly  would 
have  to  penetrate  a  leg  or  the  neck. 

No  example  of  blood  that  could  be  attributed  to  snakes 
was  found  among  the  forty-four  cases,  but  the  python 
certainly  must  be  counted  as  a  source  of  food.  On 
Kimmi  in  1914  I  came  upon  a  small  specimen  lying  among 
marshy  grass  close  to  the  water,  and  two  flies  were  on 
it,  one  of  which  had  the  swollen  red  body  indicative  of 
a  good  feed.  Other  snakes  also  seem  to  be  attractive, 
for  on  Ngamba  in  1914  I  saw  a  black  species  lying  on 
rocks  about  to  shed  its  skin  and  in  the  usual  lethargic 
condition.  Two  male  flies  were  upon  it  and  were 
obviously  attracted  by  it,  though  they  did  not  seem 
desirous  of  feeding. 

Lastly,  the  lung  fish,  Protopterus  (the  "  Mamba "), 
has  been  suggested  as  a  source  of  food,  though  I  do  not 
understand  how  it  could  serve  as  such,  seeing  that  it  only 
appears  at  the  surface  of  the  water  for  a  brief  interval 
to  obtain  a  supply  of  air.  Examination  of  its  blood  showed 
that  it  is  a  physical  impossibility  for  the  fly  to  feed  upon 
it,  for  the  corpuscles  are  so  enormous  that  only  one  at 
a  time  could  pass  up  the  proboscis,  which  would  require 
a  very  great  effort  of  suction  on  the  part  of  the  fly  ! 

The  figures  that  have  been  given  represent  the  result 
of  examination  of   many  thousands   of  wild   flies.     For 


40    NATURAL  HISTORY  OF  GLOSSINA  PALPALIS 

out  of  a  large  number  caught  on  a  given  day  only  a  few 
would  contain  fresh  blood,  and  in  these  cases  a  proportion 
would  be  mammalian  blood.  In  the  other  cases  many 
would  be  merely  recognizable  as  nucleated  non-mammalian 
blood,  and  in  only  a  very  small  proportion  would  the 
corpuscles  be  sufficiently  unaltered  to  allow  of  measure- 
ments being  taken. 

During  this  work  note  was  taken  of  the  presence  or 
absence  of  Trypanosomes  in  the  gut  of  the  fly,  and  in  the 
proboscis.  Certain  Trypanosomes  (e.g.  T.  vivax,  which 
kills  goats  very  quickly)  only  develop  in  part  of  the 
proboscis  and  are  not  found  in  the  gut ;  but  others,  such 
as  gambiense,  may  be  found  in  both. 

Of  600  flies  examined  at  Jinja,  11  per  cent,  contained 
Trypanosomes  in  the  gut  ;  of  695  on  Damba,  34  per 
cent,  had  Trypanosomes ;  and  on  Bugalla  1,000  flies 
showed  Trypanosomes  in  the  gut  in  1*7  per  cent,  of  the 
total.  Out  of  638  cases  in  which  the  proboscis  was 
examined  on  Bugalla,  14  had  Trypanosomes  in  the 
proboscis  alone  ;  i.e.  2*2  per  cent,  of  the  wild  flies  appear 
to  be  infected  with  Trypanosoma  vivax. ^ 

It  must  not  be  supposed  that  all  the  Trypanosomes 
found  in  wild  flies  are  gambiense  :  some  are  devived  from 
the  crocodile  {T.  grayi),  and  so  far  as  is  known  are  harm- 
less. 

Besides  Trypanosomes  bacilli  are  often  found  in  count- 
less numbers  in  the  gut  of  the  fly,  but  in  a  different  part. 
Nevertheless  there  appears  to  be  some  inverse  relation 
between  the  two,  for  out  of  six  hundred  flies  at  Jinja, 
in  only  3' 4  per  cent,  of  flies  containing  bacilli  were 
Trypanosomes  also  found,  and  in  only  61  per  cent,  of 
flies  containing  Trypanosomes  were  bacilli  found. 
Bacilli  were  present  in  19-3  per  cent,  and  Trypanosomes 

^  Dr.  Duke  has  shown  that  the  Situtunga  is  a  natural  host  of  T.  vivax 
as  well  as  of  T.  gambiense.  ReiJort  No.  XII  of  the  Sleeping  Sickness 
Commission,  p.  122. 


o 


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3 


12. 


v^ 


,»o  *t  —  o    a-  »    r*-,*  V 


u 

l<! 

CS 

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2- 

a; 

:=  J3 

5j 

J-   •)*-*-    o 


To  face  p.  40. 


BACILLI  AND  TRYPANOSOMES   IN  THE  FLY    41 

in  11  per  cent,  of  the  wild  flies.  Thus  there  is  marked 
incompatibility  between  the  two. 

Since  I  have  found  bacilli  in  the  gut  of  freshly  hatched 
flies,  and  even  in  pupae,  their  presence  in  the  fly  may  have 
something  to  do  with  the  fact  that  only  a  few  out  of  a 
batch  of  flies  fed  upon  an  infective  animal  at  the  same 
time  will  prove  suitable  hosts  and  will  subsequently  be 
found  to  contain  Trypanosomes.  It  may  be  that  the 
presence  of  bacilli  in  numbers  is  inimical  to  the  Trypano- 
some,  or  merely  that  they  are  present  in  flies  which  for 
some  other  reason  are  physiologically  unsuited  to  the 
development  in  them  of  the  Trypanosome.  It  would 
be  interesting  to  note  the  presence  or  absence  of  baciUi 
in  flies  which  contain  T.  vivax  only  in  the  proboscis. 

One  of  the  points  set  me  to  be  investigated  was  whether 
palpalis  can  feed  on  anything  except  blood.  I  have  not 
been  able  to  obtain  any  evidence  that  vegetable  juices 
are  sucked  up  save  that  on  Damba  Isle  I  several  times 
found  grains  of  banana  starch  in  preparations  made  from 
the  gut  of  flies.  I  am  inclined  to  think,  however,  that 
this  was  accidental  contamination  of  the  preparation, 
perhaps  from  a  cloth  used  to  wipe  the  slides,  for  it  is 
difficult  to  see  how  such  material  as  banana  could  be 
sucked  up  the  narrow  proboscis  of  Glossina.  Small 
fragments  of  vegetable  tissue  were  sometimes  met  with 
in  preparations  from  the  gut  of  a  fly,  but  I  am  disposed 
to  think  that  they  had  been  sucked  up  in  water,  for 
pieces  of  alga  were  also  found. 

Flies  paid  no  attention  to  juicy  papai  fruit  taken 
down  to  the  shore,  although  I  have  seen  a  mosquito 
greedily  feeding  thereon. 

There  seems  more  evidence  that  palpalis  imbibes 
water,  but  though  they  have  often  been  seen  sitting  on 
wet  mud,  no  fly  has  ever  been  seen  with  its  proboscis 
lowered  into  the  water. 

Examination    of    the    contents   of   the  gut   of   many 


42    NATURAL  HISTORY  OF  GLOSSINA  PALPALIS 

hundreds  of  flies  on  Damba  and  Bugalla  Islands,  as  well 
as  at  Jinja  on  the  mainland,  has  shown  various  forms 
of  algae  and  other  low  vegetable  organisms  that  must 
have  come  from  water  ;  and  once  a  very  minute  ostracod 
crustacean,  only  about  three  times  the  length  of  a 
human  red  blood  corpuscle,  was  found.  Figures  of 
these  are  given  in  my  first  and  second  reports. 

Experiments  were  made  to  see  if  flies  lived  longer  when 
able  to  obtain  juice  from  fruit  than  when  starved,  but 
access  to  fruit  made  no  difference.  The  longest  time  for 
which  a  wild  fly  has  been  kept  without  food  or  with  only 
fruit  juices  available  is  nine  days  ;  a  freshly  hatched 
fly  will  live  for  eleven  days.  After  a  single  feed  of  blood 
a  fly  lived  for  fifteen  days  (the  longest  period).  This 
is  a  remarkably  short  period,  and  if  it  is  so  in  natural 
conditions  is  rather  surprising.  Animals  such  as  ticks 
appear  to  be  able  to  live  for  months  after  a  single  feed  of 
blood;  the  fly,  however,  is  a  more  active  creature,  and 
lives  at  a  higher  rate. 

What  is  the  natural  length  of  life  of  palpalis  ?  This 
was  one  of  the  first  things  to  be  settled  when  I  went 
out  in  1910.  For  it  was  then  not  at  all  clear  why  the 
flies  on  the  lake  shore  continued  to  be  infective  several 
years  after  the  presumed  sources  oi~Trypanosoma  gambiense 
(i.e.  the  natives)  had  been  removed  from  reach  of  the  fly. 
There  were  two  possibilities — either  the  fly  was  acquiring 
infection  from  some  wild  animal,  or  the  same  flies  were 
still  alive  on  the  shore  that  had  been  the  cause  of  the 
epidemic  some  years  before.  It  was  not  until  1911  that 
Duke  showed  what  the  reservoir  of  gambiense  was,  and  I 
have  showed  that  the  fly  probably  does  not  live  for  more 
than  one  year.  The  drier  months  of  the  year  cause  a  large 
falling  off  in  numbers,  so  that  a  fly  which  has  been  living 
for  some  months  probably  succumbs  when  the  trying 
period  of  diminished  humidity  comes  at  the  beginning 
of  the  year. 


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51 

INFLUENCE   OF   CLIMATE   ON   NUMBERS   AND    PROPORTIONS   OF 

FLIES   AT  JINJA,    ON   MAINLAND. 
By  permission  of  the  Royal  Society  and  the  Controller,  H.M.  Stationery  Office. 


To  face  p.  42 


DURATION   OF  LIFE  43 

A  chart  made  at  Jinja  in  1910  (see  Chart  II) 
shows  very  clearly  the  direct  relation  between  relative 
humidity  of  the  atmosphere  and  the  number  of  flies  that 
could  be  caught. 

In  order  to  estimate  the  length  of  life  of  the  wild  fly, 
the  method  adopted  was  one  that  had  been  used  by 
Dr.  Bagshawe  to  ascertain  how  far  the  fly  would  follow 
canoes  or  men. 

Large  numbers  of  flies  were  captured,  a  portion  of  one 
leg  was  amputated  through  the  middle  of  either  femur  or 
tibia  (limbs  may  be  lost  at  a  joint  naturally,  but  never 
in  this  way),  and  then  the  fly  was  liberated.  By  con- 
tinually catching  flies  at  the  same  point  day  after  day 
it  could  be  ascertained  for  how  long  a  marked  fly  had 
lived. 

Since  a  fly  has  six  legs  and  each  can  be  marked  in  two 
ways,  twelve  markings  are  possible  :  one  method  of  marking 
was  kept  for  the  flies  of  each  week.  At  Jinja,  between 
July  27th  and  October  15,  1910,  some  eight  thousand 
flies  were  so  marked,  and  eight  markings  were  used,  an 
average  of  a  thousand  to  each  marking. 

Between  August  3rd  and  February  11th,  careful  exami- 
nation was  made  of  each  fly  caught  by  the  boys,  who 
worked  every  day  for  four  or  five  hours.  On  January 
31st,  1911,  a  female  fly  was  taken  that  had  been  marked 
on  one  of  the  days  July  27  to  August  2,  1910,  and  on 
December  29th  a  male  was  taken  that  had  been  marked 
on  one  of  the  days  July  27  to  August  2.  This  gives 
a  period  of  life  of  at  least  182  days  for  the  female  and 
149  days  for  -the  male,  but  it  is  of  course  impossible  to 
say  for  how  long  before  the  marking  the  flies  had  been 
alive  :  probably  they  were  hatched  fairly  recently. 

On  Bugalla  Island  in  1912  this  experiment  was  repeated, 
and  between  March  18th  and  April  26th  nine  thousand 
flies  were  marked  in  six  different  ways.  The  last  marked 
flies  to  be  caught  were  noted  on  January  17,  1913  :   two 


44    NATURAL  HISTORY  OF  GLOSSINA  PALPALIS 

males  that  had  been  marked  between  April  1st  and  6th. 
This  gives  a  minimum  duration  of  life  of  247-253  days 
for  the  male.  A  female  fly  caught  again  on  August  17th 
had  been  marked  between  April  8th  to  13th,  so  it  had 
lived  at  least  126  to  131  days.  This  was  not  quite  so 
long  as  the  longest  Jinja  period  (182  days).  Thus  it  was 
established  that  palpalis  can  live  for  several  months,  but 
the  probability  is  that  it  does  not  survive  a  second  dry 
season.  In  both  experiments  the  last  flies  were  caught 
at  a  time  when  the  relative  humidity  of  the  air  was 
low. 

Both  at  Jinja  in  1910  and  on  Bugalla  in  1911-12  care- 
ful meteorological  data  were  kept,  and  the  influence  of 
climatic  conditions  upon  the  total  number  of  flies  that 
were  caught  per  boy  per  hour  was  found  to  be  very 
interesting  (see  Chart  III). 

In  those  days  the  male  catch  alone  was  not  used  as  a 
means  of  estimation. 

The  number  of  flies  caught  at  Jinja  on  the  mainland 
varied  directly  with  the  relative  humidity  of  the  atmosphere, 
which  itself  varied  during  the  period  from  the  beginning 
of  August  to  the  end  of  January  from  63  per  cent,  to 
76  per  cent,   (see  Chart  II). 

On  the  other  hand,  on  Bugalla  Isle  no  such  relationship 
could  be  made  out,  but  here  the  relative  humidity  only 
varied  from  77  per  cent,  to  72  per  cent,  during  a  continuous 
period  of  twelve  months.  On  the  mainland  there  was  a 
very  decided  inverse  relation  between  the  number  of 
flies  caught  and  the  temperature.  In  the  hotter  (and  drier) 
months  there  were  fewer  flies.  This  did  not  seem  to  be 
so  markedly  the  case  on  Bugalla,  probably  because  the 
humidity  of  the  atmosphere  was  so  much  more  constant 
on  the  island  that  a  higher  temperature  did  not  necessarily 
kill  oflt  the  flies. 

In  this  fact  may  be  the  explanation  of  the  occurrence 
of  flies  on  Nsadzi  at  the  west  end,  where  there  was  so 


*)  %  >  WW 

i-        r-'--*  ~*    w    W    a   J 


3     Q 


a  r  ;§ 


CJ      11 


O     a; 


.r-T-T-'r 


a.?~  p:  ?-  SCrS   S  "J   ^  f*  :-   ?   <>■  "fi   '~"?   1  +  ~>  "   - 


To  fa:e  p.  ^4. 


INFLUENCE   OF  CLIMATE  45 

little  shade  :  the  humidity  of  the  island  atmosphere 
saved  them  from  the  heat  that  might  have  been  fatal 
on  the  mainland. 

Secondly,  the  hunger  of  females,  as  estimated  by  the 
numbers  caught,  is  very  dependent  upon  the  temperature. 
Fiske  proved  to  me  in  1914  that  the  female  percentage 
is  not  an  indication  of  the  actual  numbers  but  of  the 
hunger  of  the  fly.  Since  the  percentage  figure  varies 
inversely  each  month  with  the  temperature,  as  is  shown 
by  the  charts  for  Bugalla  and  Jinja,  it  follows  that  the 
hotter  the  month  the  less  the  fly  is  inclined  to  bite. 
Indeed,  I  have  noticed  on  individual  days  that  the  fly 
bites  less  during  the  hottest  hours,  and  less  on  a  brilliant 
sunny  day  than  when  the  sun's  heat  is  tempered  by  thin 
cloud. 

A  further  effect  of  climate  was  noted  on  Bugalla, 
namely,  upon  the  number  of  pupae  that  could  be  found 
each  month  (see  Chart  IV). 

At  the  end  of  every  month  the  boys  visited  certain 
well  known  sites  much  liked  by  palpalis  for  its  pupae, 
and  an  average  figure  was  obtained  called  "  pupae  per 
boy  "  to  indicate  empirically  the  number  found  per 
month.  It  is  obvious  that  the  total  number  found  at 
the  end  of  each  month  must  depend  in  part  upon  the 
number  of  female  flies,  which  is  indicated,  at  least  as 
regards  the  number  of  hungry  flies,  by  the  *'  female-boy- 
hour  "  figure  for  the  month. 

If  the  "  pupae-boy  "  figure  be  divided  by  the  latter 
figure,  the  quotient  may  be  used  as  a  means  of  comparing 
from  one  month  to  another  the  rate  of  reproduction, 
bearing  in  mind  that  the  times  when  the  flies  are  hungriest 
will  thus  appear  as  months  when  the  reproduction  figure 
"pupae  per  female  "  is  lowest. 

Thus,  the  average  number  of  pupae  found  per  boy  in 
the  given  time  at  the  end  of  February  was  187-3  ;  the 
average  number  of  females  caught  per  boy  per  hour  during 


46    NATURAL  HISTORY  OF  GLOSSINA  PALPALIS 

187-3 
that  month  was  6-3.  =  29*7,  which  is  the  "  pupae 

D'  o 

per  female  "  figure  for  the  month. 

If  these  figures  are  plotted  out  for  the  twelve  months, 
it  is  seen  that  the  curve  thus  formed  is  inverse  to  the  curve 
of  relative  humidity.  This  may  be  a  definite  adaptation 
to  enable  Glossina  to  tide  over  the  drier  months,  which 
are  adverse  to  the  adult  fly.  That  is,  during  the  drier 
months  (of  lessened  humidity)  more  pupae  are  deposited, 
the  pupa  being  resistant  to  a  greater  degree  to  adverse 
climatic  influences  than  is  the  perfect  fly. 

Experiments  were  performed  to  test  the  vitality  of  pupae 
exposed  to  various  conditions  of  dampness  or  drought. 
Batches  of  pupae  were  submerged  in  water  daily  for  difiPer- 
ent  lengths  of  time,  and  it  was  found  that  daily  submersion 
for  twelve  hours  on  twelve  successive  days  only  destroyed 
36  per  cent,  of  the  pupae,  and  that  only  33  per  cent,  were 
destroyed  by  four  submersions  of  twenty-four  hours, 
with  an  interval  between  each  of  twelve  hours.  The 
effects  of  continuous  submersion  were  tried,  and  it  was 
found  that  a  period  of  108-120  hours  is  necessary  to 
destroy  all  the  pupae  in  a  batch. 

Flotation  on  the  surface  can  be  borne  for  eight  days, 
but  ten  days  are  fatal. 

Pupae  were  also  put  in  a  small  wooden  box  covered 
with  one  inch  of  earth,  and  the  box  was  sunk  in  the  ground 
flush  with  the  surrounding  surface  and  left  exposed 
to  the  sun  during  the  hottest  hours  of  the  day.  A  single 
exposure  up  to  six  hours  does  not  harm  the  pupae,  but 
if  uncovered  by  earth  a  single  hour  is  fatal.  The  effect  of 
repeated  exposures  on  successive  days  was  then  tested  : 
two  hours  daily  for  three  days  made  very  little  difference 
to  the  pupae,  but  three  hours  daily  for  three  days  resulted 
in  only  2  per  cent,  of  flies  emerging  ;  six  hours  daily  for 
two  days  killed  all.  Lastly,  alternate  submersion  and 
exposure    are   fatal  ;     although    a   single   submersion    of 


•a  a  4 


O 


O    M    ^ 


a.  CQ 


•siEiuaj  jsd  asdnj; 


To  face  p.  46, 


FLUCTUATIONS  IN  NUMBERS  47. 

twelve  hours,  or  four  hours  exposure  to  sun  have,  alone, 
very  little  effect,  if  the  pupae  were  submerged  one  night 
and  exposed  to  sun  next  day  only  one  per  cent,  developed 
into  flies  ! 

Besides  variations  in  numbers  of  the  fly  due  to  climatic 
conditions,  I  found  in  1914  interesting  variations  that 
were  very  puzzling.  The  small  islands  Bulago,  Kimmi, 
Tavu  and  Ngamba  were  each  visited  weekly  from  the 
camp  on  Kome,  and  catches  were  made  of  flies  at  the 
same  spots  around  the  coast. 

It  soon  became  obvious  that  the  numbers  of  flies  (as 
estimated  by  the  number  of  males  caught  per  boy  per 
hour)  on  each  of  the  four  islands  did  not  vary  concurrently, 
and  that  variations  did  not  affect  the  sexes  in  the  same 
way  on  the  same  island  (see  Charts  V  and  VI). 

On  Bulago,  for  instance,  on  the  south  point  and  west 
shore  the  two  sexes  on  the  whole  varied  together,  but 
on  the  shore  of  the  north  bay  they  varied  inversely. 
In  the  forest  of  the  north  point  the  variations  in  number 
of  the  males  were  very  great,  while  the  number  of  females 
kept  very  constant.  On  Kimmi  it  was  noted  that  the 
catches  from  two  localities  on  the  north  and  north-west 
shores  of  the  island,  taken  together,  varied  inversely  to 
the  catches  from  the  south  and  south-east  shores,  though 
this  was  less  marked  after  the  beginning  of  July.  This 
must  mean  that  at  certain  times  the  male  flies  found  the 
north  shore  more  congenial,  whereas  at  others  they 
congregated  on  the  south  side  of  the  isle. 

By  charting  together  the  figures  representing  the 
average  catch  per  boy  per  hour  of  males  and  females  for 
each  of  the  four  islands,  a  curious  and  interesting  point 
was  brought  to  light. 

On  the  island  where  the  number  of  males  shows  the 
greatest  fluctuations  the  female  figure  shows  least,  and 
vice  versa,  and  the  same  was  found  to  hold  good  for 
individual  localities  on  Bulago  Island.     On  Tavu  Island 


48     NATURAL  HISTORY  OF  GLOSSINA  PALPALIS 

the  curve  for  male  flies  shows  great  variation,  the  female 
curve  little,  but  on  Kimmi  the  female  curve  is  the 
greater  variant  and  the  male  curve  more  constant.  It 
may  be  that  the  supply  of  food  on  Tavu  is  so  good  that 
the  females  are  well  fed  and  do  not  come  in  any  numbers 
to  be  caught  by  the  fly  boys,  whereas  on  Kimmi  the  food 
supply  is  more  erratic  :  it  must  be  said,  however,  that 
there  is  no  direct  evidence  for  this. 

A  very  interesting  relation  was  made  out  on  Tavu 
between  the  number  of  flies  caught  at  the  weekly  visits 
and  the  number  of  crocodiles  seen  when  the  island  was 
circumnavigated  in  the  canoe  before  a  landing  was  made 
at  each  visit.  There  was  a  large  flat  topped  rock  on  the 
east  coast  forming  a  little  plateau  that  was  always  in  use 
by  crocodiles  as  a  basking  place  ;  the  number  on  it 
varied  from  one  to  four,  and  others  were  seen  in  the  water. 
On  one  visit  as  many  as  fifteen  large  crocodiles  were 
seen  on  or  about  this  small  island,  and  on  that  day  the 
number  of  flies  was  at  the  rate  of  ninety-three  per  boy 
per  hour !  The  lowest  figure  was  fifty-six  per  boy- 
hour  when  only  two  crocodiles  were  seen.  The  accom- 
panying chart  shows  well  the  concurrent  variation  in 
numbers.  It  must  be  confessed  that  the  explanation  of 
this  is  not  at  all  clear.  One  would  have  rather  expected 
that  when  there  was  an  abundant  supply  of  food  on 
the  island  the  flies  would  have  been  less  hungry,  so  that 
fewer  would  have  been  attracted  by  men,  and  the  catch 
would  have  been  less  instead  of  greater  the  more  crocodiles 
there  were  within  reach.  On  the  other  hand,  had  this 
relation  been  noticed  at  one  spot  on  a  continuous  length 
of  mainland  shore  it  could  quite  well  be  explained  by 
the  wanderings  of  flies  in  search  of  food  which,  finding 
abundance  at  one  spot,  remained  there. 

But,  as  has  been  pointed  out,  there  is  no  ground  for 
believing  that  flies  cross  to  Tavu  over  the  open  water 
separating  it  from  the  larger  Kome  and  Bulago. 


AN    AM  HATCH    TREK. 


^'^ 


FLY   BEACH    ON    KIMMI. 
Behind  a  row  of  Ambatch  trees  on  the  right. 


To  face  p.  48. 


ITS  ENEMIES  49 

It  is  noteworthy  also  that  this  explanation,  were  it 
possible,  would,  be  opposed  by  the  fact  that  the 
number  of  females  caught  on  Tavu  varied  very  little, 
unlike  the  male  figure,  whereas  if  the  flies  had  been  more 
attracted  to  Tavu  on  days  when  the  crocodiles  were 
numerous,  there  should  have  been  greater  variations  in 
the  female  catch ;  perhaps  an  inverse  relation  to  the 
number  of  crocodiles. 

The  explanation,  however,  may  be  connected  with 
the  pairing  of  the  flies,  Male  flies  flock  to  the  coast  from 
out  of  the  forests  when  crocodiles  are  there  in  numbers 
in  order  to  meet  the  females,  which  go  to  feed  on  the 
crocodiles.  When  crocodiles  are  fewer  on  the  coastline 
the  male  flies  may  confine  themselves  more  to  the  forested 
centre  of  the  island  :  the  boys  caught  always  on  the 
east  and  west  shore  and  not  in  the  central  forest.  It 
will  be  remembered  that  on  Bulago  and  Kimmi  the  flies 
seemed  to  frequent  different  parts  at  different  times. 

Having  considered  two  influences  that  affect  the  num- 
bers of  the  fly,  viz.  food  and  climate,  it  will  be  interesting 
now  to  deal  with  the  natural  enemies  of  Glossina 
palpalis  in  all  its  stages. 

Considerable  attention  was  paid  to  this  question,  and 
I  have  spent  very  many  hours  observing,  in  the  haunts 
of  the  fly,  birds  and  insects  that  might  be  expected  to 
destroy  the  fly. 

Very  many  insects  suffer  great  mortality  in  their  im- 
mature stages  of  egg,  larva  and  pupa,  but  it  will  be 
obvious  from  what  has  been  said  about  the  reproduction 
of  Glossina  that  it  is  hardly  likely  that  any  great  destruc- 
tion can  be  wrought  upon  egg  or  larva  while  within  the 
body  of  the  adult  fly.  It  seemed  possible,  however,  that 
the  fat  grub  in  the  fly  might  be  "  stung "  by  some 
parasite  such  as  the  Hymenopterous  "  Ichneumon  flies," 
and  that  after  it  had  been  extruded  the  adult  parasites 
might  emerge  from  the  pupa. 

5 


50    NATURAL  HISTORY  OF  GLOSSINA  PALPALIS 

Accordingly  I  made  some  efforts  to  obtain  the  larvae 
from  pregnant  flies  captured  when  the  larva  was  far 
advanced  in  growth  and  kept  in  a  cage,  fed  at  regular 
intervals,  until  the  larva  had  been  extruded.  But 
premature  expulsion  of  the  larva,  ending  in  its  death, 
took  place  so  often  that  the  attempt  was  given  up. 

The  next  opportunity  afforded  to  enemies  is  the  brief 
moment  after  the  larva  has  been  extruded  and  is  scramb- 
ling over  the  surface  of  the  sand  in  the  endeavour  to  find 
a  spot  where  it  can  penetrate  and  hide  itself.  I  have 
watched  this  happen  ;  the  birth  of  the  larva  in  the  eight 
cases  witnessed  took  place  between  10' 45  a.m.  and  1  p.m. 
It  is  very  active,  but  being  white  with  black  bosses 
at  the  posterior  extremity,  is  quite  conspicuous  as  it 
wriggles  over  the  surface.  On  several  occasions  I  have 
placed  the  larva  in  front  of  a  species  of  ant,  Paltoihyreus 
tarsatus,  and  seen  the  ant  pick  up  the  larva,  give 
it  several  nips  with  its  large  mandibles,  and  carry  it 
off.  Once,  on  arrival  at  the  breeding  ground,  among 
some  bushes  where  I  used  to  lie  and  watch  for  events, 
I  saw  one  of  these  ants  wandering  about  with  a  larva 
in  its  mandibles. 

This  ant  was  very  often  seen  on  the  beaches  where  the 
fly  breeds,  wandering  about  and  evidently  searching  for 
food,  and  no  doubt  it  does  occasionally  destroy  a  larva, 
as  was  once  seen.  But  it  cannot  often  enough  happen 
to  meet  a  larva  before  it  disappears  into  the  ground  to 
be  of  value  as  a  controller  of  the  numbers  of  the  fly.  Birds 
also  may  occasionally  pick  up  the  larva  while  it  is  thus 
exposed,  but  it  can  only  happen  rarely. 

The  greatest  destruction  of  Glossina  by  enemies  probably 
takes  place  during  the  several  weeks  that  it  lies  just  below 
the  surface  of  the  soil  as  an  inert  pupa,  but  I  have  obtained 
no  evidence  of  any  vertebrate  enemy.  No  traces  have 
ever  been  seen  on  a  breeding  ground  such  as  would  be 
left  by  a  bird  scratching  the  surface  as  do  game  birds. 


ENEMIES   OF  THE   PUPA  51 

It  will  be  said  that  there  were  no  guinea  fowl  or 
francolins  (save  a  single  forest  francolin)  on  the  islands. 
Nor  have  any  evidences  of  the  activities  of  such  an 
animal  as  a  shrew  been  found  on  the  breeding 
grounds.  The  most  important  enemies,  therefore,  will 
be  insects,  and  accordingly  efforts  were  made  to  breed 
out  from  the  pupae  such  enemies  as  the  Chalcididae, 
Hymenopterous  parasites  or  "  Ichneumon  flies  "  of 
minute  size  which  lay  their  eggs  in  the  immature  stages 
of  other  insects,  particularly  the  eggs  and  pupae,  as  butter- 
fly breeders  know  to  their  cost  ! 

On  Damba  Island  five  thousand  eix  hundred  pupae 
were  kept  in  boxes  with  closely  fitting  glass  lids,  but 
not  a  single  one  yielded  any  Chalcids,  although  from  the 
pupa  of  another  species  of  fly  obtained  with  Tse-tse 
pupae  a  species  of  Chalcid  did  emerge. 

However,  I  felt  certain  that  Glossina  pupae  were  attacked, 
for  occasionally  an  empty  pupa  case  was  found  with  the 
minute  circular  hole  in  the  shell  through  which  the  Chalcids 
had  emerged.  At  last,  on  Wema  Isle  in  1914,  when  Fiske 
and  I  were  opening  numbers  of  pupae  to  observe  the  stage 
of  development,  he  found  one  filled  with  rows  of  little 
white  Chalcid  pupae,  looking  like  mummies  with  black 
eyes.  I  obtained  more  pupae  from  that  locality  and 
succeeded  in  rearing  some  of  the  Chalcids,  which  proved 
to  be  a  new  species  that  has  been  named  Syntomosphyrum 
glossinae. 

It  has  been  mentioned  that  some  Glossina  pupae  were 
found  with  the  minute  round  hole  made  by  the  Chalcid, 
but  others  are  quite  commonly  found  with  holes  of  much 
larger  size  and  of  jagged  outline.  I  have  never  been 
able  to  ascertain  what  is  the  insect  responsible  for  this, 
but  in  the  case  of  the  allied  species  Glossina  morsifans, 
a  species  of  Mutilla  (ant-like,  wingless,  fossorial  Hymenop- 
tera)  has  been  found  to  be  responsible.  The  female 
Mutilla  deposits  her  egg  in  the  Glossina  pupa,   and  its 


52    NATURAL  HISTORY  OF  GLOSSINA  PALPALIS 

larva  destroys  the  Glossina.  It  has  since  been  found  out 
that  the  Chalcid  Syntomosphyrum  destroys  not  the 
Glossina  but  the  Mutilla,  which  has  itself  destroyed  the 
Glossina,  so  that  this  Chalcid  works  on  the  side  of  and 
not  against  Glossina. 

When  the  adult  fly  has  broken  through  the  end  of  the 
pupa  case  and  pushed  its  way  up  through  the  loose  soil 
covering  it,  it  seeks  for  a  stem  up  which  to  crawl  so  that 
it  may  rest  with  the  wings  hanging  vertically  downwards 
while  they  stretch  and  dry.  At  this  time  the  fly  is  a 
soft  white  juicy  morsel,  and  any  ant  that  happened  upon 
it  would  find  a  pleasant  meal.  But  the  fly  seems  to 
realize  its  danger,  and  is  very  much  on  the  alert.  More- 
over, its  legs  are  surprisingly  firm,  although  it  appears 
so  weak  :  I  have  several  times  watched  newly  hatched 
specimens  resting  on  a  pebble  until  the  wings  had  har- 
dened, and  if  an  ant  came  near  enough  to  be  dangerous 
they  would  quickly  sidle  away. 

An  interesting  insect,  the  "  ant  lion,"  makes  its  conical 
pits  in  the  dry  loose  sand  used  as  breeding  grounds  by 
Glossina,  and  lies  in  wait  at  the  bottom  ready  to  seize 
such  insects  as  fall  into  the  pit.  Since  these  pits  are  often 
very  numerous  in  the  soil  over  which  the  freshly  emerged 
fly  has  to  scramble,  the  helpless  insect  must  sometimes 
fall  into  one  of  these  pits  and  be  devoured  before  the 
wings  have  expanded,  and  I  have  actually  seen  one  as 
it  scrambled  along  fall  down  a  pit.  But  the  "  ant  lion  " 
had  either  pupated  or  was  not  hungry,  for  it  paid  no 
attention  and  the  fly  scrambled  out  again. 

These  pits  are  often  so  abundant  in  the  very  spots 
selected  by  the  fly  for  its  larvae  to  burrow  in  that  I  think 
it  cannot  be  uncommon  for  the  freshly  hatched  flies  to 
fall  in  and  be  devoured. 

Much  time  has  been  spent  in  observational  work  on 
possible  enemies  of  the  adult  fly.  On  Damba  Island 
forty-four  insectivorous  birds  feeding  in  the  fly  belt  were 


ENEMIES   OF  THE  FLY  53 

examined,  and  the  stomachs  searched  for  the  wings  of 
Glossina,  easily  recognizable  by  their  peculiar  venation, 
but  none  were  ever  found  to  have  swallowed  Olossina. 
Twenty  more  birds  were  shot  on  Bugalla  with  similar 
results. 

A  common  green  tree  frog  was  examined,  and  in  fifty- 
three  cases  no  Glossinae  were  found  in  the  stomachs.  This 
species  spends  the  day  among  the  vegetation  on  the 
shore,  but  I  think  only  feeds  at  night,  so  that  it  is  not 
likely  to  meet  with  Glossina. 

A  large  Agamid  lizard  haunts  trees,  around  which  there 
is  a  certain  space  of  open  ground,  and  I  shot  five  of  them, 
but  their  stomachs  were  found  to  contain  only  ants. 

It  does  not  seem  probable,  in  view  of  the  above  evidence, 
that  vertebrates  play  a  great  part  in  keeping  down  the 
numbers  of  the  adult  fly. 

Of  invertebrate  enemies  of  the  fly  there  is  no  doubt 
that  species  of  Bembex,  sand-wasps  or  Fossors,  are  of 
some  value,  but  their  distribution  is  very  local. 

A  full  account  of  these  most  fascinating  insects  will 
be  found  in  the  chapter  on  Hymenoptera  :  it  suffices  to 
say  here  that  two  species  ^  have  been  seen  to  store  up 
Glossina  in  their  underground  burrows,  and  that  they  seem 
to  know  that  fat  full-fed  flies,  which  they  prefer  for  the 
food  of  their  larvae,  are  to  be  obtained  from  man  and 
other  animals.  I  have  seen  the  same  in  the  case  of  a 
species  (unidentified)  which  preys  upon  Glossina  morsitans  : 
as  one  walked  along,  pursued  and  harassed  by  the  Tse- 
tse, the  Bembex  would  accompany  one,  flying  round  and 
round  searching  for  a  fat  fly. 

A  species  of  Dragon  fly  (Cacergates  leucosticta)  which 
is  very  common  on  the  lake  shore  has  discovered  the 
same  thing,  and  individuals  have  several  times  been  seen 
to  chase  Glossina,  and  once  or  twice  I  have  actually  seen 
them  catch  and  devour  the  fly.     On  one  occasion  I  was 

*  B.  forcipala,  B.  capensis. 


54    NATURAL  HISTORY  OF  GLOSSINA  PALPALIS 

able  with  glasses  to  see  Cacergates  in  attendance  on  a 
hippo  that  was  grazing  on  Bugalla  fly  ground,  evidently 
on  the  look  out  for  flies  full  of  hippo  blood  ! 

Predaceous  two-winged  flies  of  the  family  Asilidae 
have  once  or  twice  been  seen  to  be  devouring  Olossinae, 
but  I  do  not  think  that  the  Asilid  is  of  any  importance 
as  a  regular  enemy. 

On  the  whole,  it  seems  that  the  chief  enemies  of  Olossina 
are  among  the  Hymenoptera,  but  I  am  inclined  to  think 
that  great  loss  of  life  does  not  result.  Olossina  has 
such  an  extraordinarily  slow  rate  of  reproduction  that 
it  can  have  few  enemies  :  the  greater  the  number  of 
offspring  the  more  must  be  destroyed  by  enemies  if  the 
species  is  to  be  kept  within  bounds,  and  vice  versa.  Clim- 
atic conditions,  in  my  opinion,  together  with  facilities 
for  breeding,  are  the  most  important  influences  affecting 
the  numbers  of  the  fly. 

We  now  come  to  the  question  of  the  "  breeding  grounds  " 
of  palpalis,  on  which  a  great  deal  of  work  has  been  done. 

The  very  peculiar  method  of  reproduction  of  the  genus 
Olossina  was  reported  by  Bruce  in  his  papers  on  Nagana  ; 
hitherto  Olossina  morsitayis  had  been  supposed  to  deposit 
its  eggs  in  buffalo  droppings,  and  this  was  held  to  account 
for  the  supposed  fact  that  this  Tse-tse  could  not  live 
apart   from   the   buffalo. 

When  palpalis  was  proved  to  be  the  carrier  of  Sleeping 
Sickness  efforts  were  made  to  discover  its  pupae,  with  a 
view  to  the  possibility  of  destroying  it  in  large  numbers 
when  it  could  be  easily  reached. 

Dr.  A.  G.  Bagshawe  ^  in  Uganda  was  the  first  to  find 
the  pupae  of  palpalis  :  they  were  deposited  around  the 
bases  of  stems  of  banana  plants.  Later  he  found  them 
sparsely  under  sundry  bushes  and  masses  of  creepers, 
but  never  in  such  great  numbers  as  can  now  be  found. 

Dr.  C.  Marshall  and  Lieutenant  A.  D.  Eraser,  R.A.M.C, 

1  Reports  of  the  Sleeping  Sickness  Commission,    1908,   IX,  p.   48. 


tHM-%-^- 


GLOSS/.\U    PALPALIS   AND    PUPAE. 

Slightly  less  than  natural  size. 

Photograph  by  A.  Robinson.- 


UPROOTED  TREE  ON  KIMMI  l^I.K 

FORMING  IDEAL  SHELTER  FOR 

PUPAE. 


H»W 


t 


SEARCHING     luK     I'LIAL      AMONG 

GRASS       TUSSOCKS        ON        SOUTH 

POINT,    BULAGO    ISLE. 


To  lace  p.  54. 


BREEDING  PLACES  55 

were  the  first  to  find  large  numbers  of  pupae,^  and  reported 
as  follows  :  "  They  were  most  readily  found  on  the 
shore  within  a  yard  or  two  of  the  edge  of  the  forest.  It 
has  since  been  found  that  the  nearer  the  forest  the  more 
plentiful  they  are  .  .  .  and  that  the  most  favourable 
place  is  close  to  the  undergrowth  that  edges  the  forests 
— in  the  loose  dry  sand  near  the  roots  of  ferns,  etc.,  and 
shaded  to  some  extent  by  the  tall  forest  trees."  This 
excellent  account  may  now  be  enlarged  upon  as  a  result 
of  many  months'  work  and  thought  devoted  to  the  breed- 
ing places  of  palpalis. 

It  may  be  pointed  out  firstly  that  there  are  two  broad 
distinctions  possible — between  large  areas  of  shore  suit- 
able, for  reasons  to  be  indicated  later,  along  much  of  its 
length  for  the  pupae,  and  isolated  spots  at  the  bases 
of  trees,  individual  rocks,  etc.,  such  as  the  spots  first 
described  by  Dr.  Bagshawe. 

The  former  large  areas  may  be  termed  "  breeding 
grounds,"  the  latter  I  have  termed  "  loci,"  and  they  will 
be  considered  in  detail. 

The  requirements  of  the  pupae  of  Glossina  palpalis 
may  be  summarized  as  follows  :  "  Loose  dry  soil,  well 
shaded,  but  with  the  surface  thoroughly  ventilated  ; 
within  a  few  yards  from  the  water  but  beyond  its  reach."  ^ 
It  is  obvious  that  the  soil  must  be  loose,  else  the  larva 
would  be  unable  to  burrow  down.  Hence,  however 
suitable  a  spot  may  be  in  many  other  ways,  if  it  is  hard 
and  bound  down  by  rootlets  of  grass  it  will  not  be  a 
good  place  for  larvae  to  burrow  into  the  soil. 

The  character  of  the  soil  is  important ;  that  it  must 
be  dry  and  well  ventilated  has  been  proved  over  and  over 
again.  A  very  interesting  observation  on  Tavu  Island 
in  1914  showed  this  very  well.     Close  to  a  very  favourite 

^  Progress  Report  on  the  Uganda  Sleeping  Sickness  Camps,  by  Dr. 
A.  D.  P.  Hodges,  1909,  Appendix  C,  "The  breeding  grounds  of  Qlossina 
palpalis.'''     The  Sleeping  Sickness  Bureau,   1909. 

2  See  my  Fifth  Report,  p.  91. 


56    NATURAL  HISTORY  OF  GLOSSINA  PALPALIS 

breeding  ground  on  a  ridge  was  an  area  of  low-lying  sand 
covered  by  dense  vegetation,  the  leaves  of  which  lying 
on  the  sand  were  mouldy  and  kept  it  damp.  My  fly 
boys  searched  for  pupae  there  unsuccessfully,  and  in  so 
doing  of  course  cleared  away  the  dead  leaves  and  opened 
up  the  vegetation,  so  that  a  small  area  of  sand  about 
two  feet  in  diameter  was  much  more  freely  ventilated, 
though  still  shaded. 

On  a  subsequent  visit  a  week  later  I  found,  in  that  very 
spot,  about  two  dozen  fresh  pupae  which  had  been  deposited 
there  since  my  former  visit.  Incidentally  this  observa- 
tion shows  a  very  important  point  which  will  be  alluded 
to  later,  that  the  female  fly  searches  carefully  for  the 
most  suitable  spot  for  the  pupae. 

The  soil  itself  may  be  of  very  diverse  kinds  :  fine 
pebbles,  pebbles  mixed  with  coarse  sand,  coarse  brown 
sand,  coarse  white  sand,  fine  white  sand,  light  friable 
earth,  vegetable  humus  and  debris,  and  the  very  fine  dry 
dust  found  in  caves  and  probably  mostly  derived  from 
disintegrated  droppings  of  bats.  Coarse  sand  with  or 
without  pebbles  has  been  found  to  yield  the  greatest 
number  of  j^upae  :  the  very  fine  white  sand  such  as  com- 
poses the  southern  beach  of  Nsadzi  (see  Fig.)  is  not  so 
suitable,  because  I  think  it  holds  moisture  too  much. 
The  very  fine  dry  dust  of  caves  does  not  seem  very  attrac- 
tive to  the  flies  ;  possibly  it  is  in  its  turn  too  dry. 

Vegetable  humus  and  debris  are  most  important,  for  on 
long  stretches  of  shore  they  often  form  the  only  material 
suitable  for  pupae,  elsewhere  there  being  only  bare  rocks. 
Little  pockets  of  humus  and  dried-up  debris  under  angles 
of  rocks  or  at  the  bases  of  trees  in  such  areas  form  the 
only  spots  in  which  the  fly  can  deposit  its  larvae,  and 
these  are  what  I  have  termed  "  loci."  Other  "  loci  " 
are  sometimes  formed  in  a'forest  by  loose  sand  up  against 
the  base  of  a  tree  trunk  not  far  from  the  water,  often 
indicated  as  suitable  for  palpalis  pupae  by  the  presence 


TREE   TRUNK   ON    BUGALI.A    ISLE    UNDER   WHICH    MANY    GLOSSIXA    PUPAE 

COULD    ALWAYS   BE    FOUND. 

By  permission  of  the  Royal  Society  and  the  Controller,  H.M.  Stationery  Office. 


BREEDING    PLACE    OF    GLOSSIXA    AT    HOLLOWED    BASE    OF    TREE    ON    BUGALLA. 
By  permission  of  the  Royal  Society  and  the  Controller,  H.M.  Stationery  Office. 

To  face  p.  56, 


BREEDING  PLACES  57 

of  the  pits  of  "  ant  lions,"  which  have  much  the  same 
requirements. 

On  the  little  Isle  of  Lula,  where  fly  was  found  in  1918-19 
to  be  so  numerous  that  the  catch  was  at  the  rate  of  56*5 
males  per  boy-hour,  there  is  nowhere  for  the  fly  to  deposit 
larv£e  except  in  *'  loci  " — there  is  no  sand  or  gravel  beach 
anywhere  on  this  rocky  little  island. 

This  figure  however  is  exceptional,  but  I  have  no  doubt 
in  my  own  mind  that  palpalis  can  exist  in  considerable 
number  on  a  coast  line  where  there  are  only  scattered 
"  loci  "  in  which  to  place  its  larvae. 

The  next  point  to  be  considered  is  shade,  which  is  of 
great  importance.  The  pupa  is  dependent  upon  protec- 
tion from  the  sun,  although,  as  I  have  shown  above,  it 
can  survive  a  certain  amount  of  exposure. 

Shade  for  pupae  may  be  either  permanent  or  variable. 
Permanent  shade  is  afforded  by  (1)  caves  or  large  rocks 
undercut  at  the  base  ;  (2)  prostrate  tree  trunks  arching 
over  the  ground  ;  (3)  hollows  at  the  base  of  or  among 
roots  of  living  trees  ;  (4)  the  pent-house  roof  formed  by  the 
disc  of  earth  torn  up  by  the  roots  of  an  overturned  tree  ; 
(5)  thick  bushes. 

I  have  not  found  caves  to  be  nearly  as  productive  as 
I  had  expected ;  on  Kimmi  Isle,  where  flies  were  caught 
at  the  rate  of  33  males  per  boy-hour,  pupae  could  only  be 
found  at  the  rate  of  6-7  per  boy-hour.  On  the  other 
hand,  at  a  locality  on  Wema  where  the  fly  rate  was  59-5 
per  boy -hour,  jnipae  were  found  at  the  base  of  an  under- 
cut rock  at  the  rate  of  72-4  per  boy-hour.  I  think  the 
soil  in  caves  is  almost  too  dry. 

Prostrate  tree  trunks  arching  low  over  the  ground 
form  ideal  sites  for  pupae,  and  the  one  illustrated  was  a 
favourite  collecting  ground  on  Bugalla,  On  the  same 
beach  on  Bugalla  and  close  to  it  was  a  tree  much  hollowed 
at  its  base,  which  is  figured  ;  it  proved  to  be  a  very  good 
collecting  ground  for  pupae. 


58    NATURAL  HISTORY  OF  GLOSSINA  PALPALIS 

When  a  tree  is  torn  up  by  the  wind  and,  unable  to 
fall,  is  held  up  by  its  neighbours,  the  roots  and  earth 
embraced  by  them  form  an  ideal  shelter  for  pupae  if  the 
tree  is  near  enough  to  water.  One  such  was  found  on 
Kimmi  in  1918-19  and  is  here  illustrated.  In  the  loose 
dry  earth  forming  an  area  of  a  few  feet  square  under  the 
roots,  four  boys  in  half  an  hour  secured  309  pupae,  giving 
a  rate  of  154-5  per  boy-hour,  which  is  extremely  high. 
Search  was  made  for  pupae  in  other  localities  near  this 
tree,  but  the  result  was  only  28  per  boy-hour  ! 

Lastly,  thick  bushes,  especially  the  "  Oluzibaziba " 
(Alchornea),  provide  shade  all  the  year  round,  and  if  the 
soil  and  other  conditions  are  suitable,  pupae  may  always 
be  looked  for  there  with  success. 

The  illustration  shows  a  very  favourite  collecting  ground 
on  the  fly  beach  of  Damba  Island  :  under  the  bushes 
close  by  but  out  of  reach  of  the  water. 

Variable  shade  is  formed  by  low  undergrowth  or  creepers 
or  dense  young  growth  of  bushes  near  the  ground.  I 
have  been  much  struck  with  repeated  evidence  of  the  fly's 
care  in  selecting  spots  where  new  young  growth  is  rapidly 
forming  dense  shade,  and  the  quickness  with  which  such 
shelter  is  seized  upon  by  the  mother  as  suitable. 

It  was  a  common  occurrence  to  find  a  cluster  of  some 
creeper  forming  a  dense  tangle  of  fresh  green  that  provided 
admirable  shade  for  the  pupae,  and  investigation  of  the 
pupae  found  there  showed  that  they  were  in  a  very  early 
stage  of  development ;  that  is  to  say,  had  been  recently 
placed  there.  On  Wema  a  very  thick  tangle  of  young 
sprouts  of  a  species  of  Polygonaceae  was  found  on  a  ridge 
of  sand,  projecting  so  as  to  arch  over  the  surface  below  : 
one  boy  found  here  eighty-eight  pupae,  of  which  91  per 
cent,  had  only  recently  been  deposited,  for  they  were 
in  a  very  early  stage  of  development. 

Moreover,  only  six  empty  cases  were  found  from  which 
the  adult  fly  had  emerged.     These  facts  show  that  the 


'  •"    ''       'I 


ENZIBAZIBA"    BUSHP:S    OX    DAMBA    ISLE    FORMING    BREEDING    GROUND. 
By  permission  of  tlie  Royal  Society  and  the  Controller,  H.M.  Stationery  Office. 


SHINGLE   AND   SAND    UNDER   SHELTERING    ENZIBAZIBA   BUSHES    WHERE    FLIES 
HAVK    BEEN    SEEN   TO    DEPOSIT    LARVAE. 

Foot-rule  set  upright  shows  scale. 

To  f.ice  p.  58- 


BREEDING   PLACES  59 

green  growth  had  only  just  reached  the  condition  deemed 
suitable  by  the  fly  as  cover  for  the  pupae.  An  opposite 
condition  was  found  on  Bulago.  A  tree  had  large  horizon- 
tal branches  near  the  surface  of  the  sand  arching  over 
which  was  a  canopy  of  half  dead  creeper,  throwing  very 
poor  shade,  but  with  some  fresh  green  shoots  springing 
out  so  that  in  a  very  little  while  it  would  form  a  good 
shelter.  Forty-five  pupae  were  found  here,  of  which 
twenty-seven  were  dead  ;  in  three  the  adult  fly  was  almost 
ready  to  hatch,  and  the  other  fifteen  were  in  the  earliest 
stage  of  development. 

These  facts  show  that  the  herbage  had  been  at  one 
time  dense  enough  to  throw  good  shade,  but  having  died, 
many  pupae  beneath  it  had  been  killed  by  exposure  to 
the  sun's  heat.  Now  that  fresh  green  shoots  were  growing 
again,  the  fly  considered  the  shelter  good  enough,  and  had 
begun  to  use  the  spot  again  as  a  nursery. 

At  another  time  a  boy  searched  for  pupae  at  the  base 
of  a  papilionaceous  tree,  which  having  thin  foliage  throws 
poor  shade,  and  in  this  case  had  recently  died.  Here 
were  found  130  shells  from  which  the  adult  fly  had  emerged, 
and  five  pupae,  all  dead.  Owing  to  the  death  of  the  tree, 
and  the  poor  condition  of  rambling  plants  around  its 
base  which  had  at  one  time  thrown  good  shade,  the  fly 
no  longer  considered  the  spot  a  suitable  one,  and  all  the 
pupae  that  had  been  deposited  there  when  the  shade  was 
good  had  either  hatched  out  or  died. 

Lastly,  among  the  requirements  of  the  pupae  is  proximity 
to  water.  The  pupa  seems  to  require  this,  although  its 
actual  surroundings  must  be  dry.  Now,  inasmuch  as 
the  optimum  conditions  of  boil  and  shade  are  provided 
by  the  raised  beaches  of  sand  or  gravel  that  have  been 
left  by  the  subsidence  of  the  lake  from  a  former  higher 
level,  these  raised  beaches  being  naturally  near  the  water 
it  might  be  argued  that  the  pupae  were  found  here  not 
because  the  beaches  were  near  the  water,  but  because  on 


60    NATURAL  HISTORY  OF  GLOSSINA  PALPALIS 

the  beaches  were  found  the  optimum  conditions.  But  a 
recent  observation,  I  think,  disposes  of  that  argument. 
On  Kimmi  Isle  in  1914  was  a  broad  flat  strip  of  low  lying 
marshy  land,  soft  and  waterlogged,  that  obviously  owed 
its  origin  to  the  level  of  the  lake  having  fallen  and  the 
water  having  receded  from  the  real  shore  marked  at 
the  edge  of  the  forest  by  the  usual  raised  beach,  which 
was  thus  separated  from  the  water  by  a  hundred  yards 
of  marshy  grass  land. 

This  raised  beach  satisfied  aU  the  requirements  of  pupae 
except  proximity  to  the  open  water,  but  no  pupae  were 
found  in  1914.  In  December  1918,  however,  there  having 
been  an  exceptionally  wet  season  in  1916,  the  water 
had  returned  to  a  former  height  and  had  covered  the 
former  marsh  land,  so  that  it  came  right  up  to  the  old 
beach,  which  thus  formed  a  typical  "  fly  beach."  It 
was  now  used  by  the  fly  as  a  breeding  ground,  and  pupae 
were  found  there. 

It  may  be  said,  then,  that  the  ideal  requirements  of 
the  fly  for  its  pupae  are  found  on  the  beaches  near  the 
water,  well  shaded,  and  composed  of  dry  sand  or  gravel, 
and  that  where  these  occur  palpalis  is  found  in  maximum 
numbers.  But  in  their  absence  the  fly  makes  use  of  such 
scattered  nooks  as  can  be  found,  so  that  it  can  exist 
in  some  number  in  the  absence  of  "  breeding  grounds  " 
on  rocky  coasts.  I  consider  this  to  be  very  important, 
for  it  has  been  thought  that  it  would  be  possible  to 
destroy  the  fly  by  merely  cutting  down  and  clearing  the 
low  shade  producing  vegetation  on  the  beaches  so  as  to 
spoil  the  breeding  grounds.  This  would  doubtless  lessen 
the  numbers  of  the  fly,  perhaps  by  half,  but  would  not 
exterminate  it. 

In  order  to  exterminate  Sleeping  Sickness  two  animals 
must  be  kept  from  each  other — the  Situtunga  antelope 
from  which  the  fly  obtains  the  Trypanosome,  and  the 
fly,  which  inoculates  the  Situtunga  with  the  Trypanosome. 


GLOSSINA  OR   SITUTUNGA  ?  61 

Each  without  the  other  is  harmless,  for  the  Trypanosome 
cannot  multiply  indefinitely  in  the  fly,  and  requires  to 
live  for  a  cycle  in  mammalian  blood. 

Can  the  Situtunga  be  exterminated  ?  This  would 
be  an  extraordinarily  difficult  matter.  It  might  be  de- 
stroyed, temporarily,  on  the  islands,  for  there  are  very 
iew  localities  where  it  would  be  out  of  reach.  But  on 
the  mainland  there  are  vast  areas  of  papyrus  swamps 
in  which  it  finds  sure  refuge  and  where  it  would  be  quite 
beyond  reach.  Now  it  is  well  known  that  the  antelope 
swims  readily,  and  I  have  given  an  example  of  its  wander- 
ings on  to  islands  where  in  the  old  days  it  was  kept  down 
by  natives.  Hence  it  would  easily  swim  out  again  to 
the  islands  from  the  mainland  papyrus  swamps,  and  from 
one  part  of  the  mainland  to  the  other.  If,  however,  a 
price  were  put  upon  its  head  and  natives  were  allowed 
to  destroy  it,  it  might  conceivably  be  kept  to  the  papyrus 
swamps,  where,  beyond  the  reach  of  Glossina,  which  is 
never  found  in  such  localities,  it  would  be  harmless. 

As  to  the  other  side  of  the  question,  whether  Glossina 
can  be  destroyed,  or  at  least  so  diminished  in  numbers 
as  to  be  harmless,  there  is  a  good  deal  to  be  said.  It  must 
be  remembered  that  when  the  fly  is  only  present  in  small 
numbers  the  chances  of  any  one  being  infective  are  minute. 
For  every  fly  does  not  feed  from  a  buck,  and  every  buck 
that  is  fed  upon  does  not  contain  Trypanosomes.  More- 
over, as  Miss  Robertson  has  shown,  if  the  buck  does 
contain  Trypanosomes  they  are  not  always  in  a  condition 
ready  to  multiply  in  the  fly  when  it  bites,  and  lastly, 
every  fly  that  takes  in  Trypanosomes  is  apparently  not  a 
suitable  medium  for  their  further  development. 

When  an  undesirable  insect  is  to  be  destroyed,  it  is 
often  found  that  the  larval  stage  is  easy  to  deal  with,  or 
the  next  stage,  when  the  insect  is  a  quiet  pupa  or 
chrysalis. 

But  since   there   is   no    free   larval    stage   in    Glossina, 


62    NATURAL  HISTORY  OF  GLOSSINA  PALPALIS 

the  pupa  is  all  that  remains  to  us.  Can  we  then 
destroy  it  ? 

This  is  theoretically  easy  since  shade  is  a  requisite.  If 
all  the  low  bushes  and  creeper  growing  on  dry  sand  near 
the  water  were  cut  down,  the  "  breeding  grounds  "  would 
be  destroyed  and  the  numbers  of  the  fly  might  be  reduced 
by  half. 

This  would  leave,  however,  all  the  "  loci  "  that  have 
been  discussed,  and  I  see  nothing  for  it  but  to  clear  all 
the  shore  of  low  bush  for  at  least  fifty  yards  back  from 
the  water,  and  probably  a  great  deal  further.  This  would 
be  a  colossal  task  with  a  lake  of  such  a  size.  But  a  better 
way  occurred  to  me  in  1914,  and  an  observation  in  1918 
on  Kimmi  that  has  been  already  quoted  made  it  seem 
very  likely  to  succeed. 

The  method  is  to  provide  for  the  fly  all  the  conditions 
that  it  requires  in  a  concentrated  form,  in  such  a  way 
that  it  will  deposit  its  pupae  in  the  place  chosen  for  it  rather 
than  elsewhere.  The  pupae  can  then  be  easily  collected 
and  destroyed.  The  conditions  required  by  the  fly 
have  been  dealt  with  above,  and  they  are  provided  by 
building  a  low  roof  of  thatch  covered  with  green  creeper 
on  a  bank  of  sand  or  gravel  near  the  water.  In  1914, 
I  had  commenced  experimental  work  on  these  lines  on 
Tavu  and  Ngamba,  which  was  cut  short  by  the  call  of 
active  service,  but  I  had  satisfied  myself  that  these 
shelters  were  attractive  to  the  fly.  I  also  found  that 
although,  as  has  been  said  before,  a  thick  layer  of  dead 
leaves  on  the  surface  is  inimical  to  the  pupae,  yet  the  fly 
prefers  the  surface  to  be  lightly  strewn  with  flakes  of  bark, 
sticks  or  dead  leaves.  In  the  preliminary  tests  one  half 
of  the  sheltered  area  was  strewn  with  bark  or  leaves  and 
the  other  half  left  bare,  but  there  were  always  more 
pupae  found  in  the  former  half. 

The  accompanying  figures  show  the  nature  of  the 
"  artificial  breeding  ground  "  thus  provided  in  the  test 


THE    RAISED    BEACH    OF    NGAMI5A    CLEARED    OF    VEGETATION    UP   TO   THE 

EDGE   OF   THE    FOREST    BEHIND. 

Two  boys  are  senrching  for  pupae  under  the  shelter. 

Rv  t'cniiissioti  of  the  Royal  Society  and  lite  Controller,  H.M.  Stationery  Office. 


?^''IZj 


THE   SHELTER   ON   THE    RAISED    BEACH    OF    TAVU,    AFTER    CLEARING. 

The  water  lies  beyond  the  reeds  on  the  right  hand. 

By  permission  of  the  Royal  Society  and  the  Controller,  H.M.  Stationery  Office. 

To  face  p.  62. 


PROPOSED  NEW  METHOD   OF  DESTRUCTION  63 

experiments  on  Tavu  and  Ngamba  in  1914.  When  I 
returned  to  the  islands  after  the  war  this  question  was 
much  in  my  mind.  It  had  seemed  probable  that  in 
order  to  prevent  the  fly  making  use  of  natural  breeding 
grounds  and  loci  it  would  be  necessary  to  clear  them, 
but  a  most  enlightening  observation  on  Kimmi  in 
December  1918  made  it  seem  probable  that  clearing 
would  be  unnecessary.  On  a  sand  bank  or  raised  beach 
the  boys  were  set  to  find  pupae,  but  found  only  a  few 
except  at  one  spot.  This  was  under  a  little  pent-house 
roof  formed  by  roots  of  a  tree  that  had  been  torn  up  by 
the  wind  but  had  been  prevented  from  falling  by  its 
neighbours.  The  earth  embraced  by  the  roots  formed  a 
roof  at  an  angle  of  forty-five  degrees  protecting  from  the 
sun  and  rain  loose  dry  soil,  and  in  an  area  a  few  feet  square 
one  boy  found  pupae  at  the  rate  of  104-5  per  boy-hour. 
This  proves  that  although  there  may  be  a  large  area  of 
well  sheltered  sand  apparently  suitable  for  pupae,  the 
fly  will  carefully  search  for  the  best  spot  and  deposit 
pupae  there  in  numbers  rather  than  scatter  them  along 
the  larger  area. 

I  also  found  numerous  other  examples  of  the  same  thing  : 
moreover,  an  experiment  has  been  cited  earlier  which 
shows  that  the  female  fly  does  circulate  round  an  island, 
partly  no  doubt  in  search  of  food  but  also  no  doubt  to 
look  for  the  best  place  for  her  young.  Indeed,  I  feel  sure 
that  the  mother  fly  searches  as  carefully  as  does  a  parent 
butterfly  for  the  right  plant  on  which  to  lay  her  eggs. 
That  being  so,  there  is  no  need  to  cut  down  the  bush, 
if  the  artificial  breeding  place  is  made  tempting  enough. 
The  construction  is  very  simple.  All  roots  are  pulled 
up  out  of  the  loose  dry  soil.  The  roof  covers  an  area 
some  twelve  by  four  feet ;  at  its  back  it  is  just  high  enough 
to  allow  a  boy  to  creep  under  in  search  of  pupae,  in  front 
it  just  clears  the  ground.  There  are  no  walls,  to  allow 
the    free    ventilation    required.     Creepers    such    as    the 


64    NATURAL  HISTORY  OF  GLOSSINA  PALPALIS 

Ipomaea  and  others  which  grow  abundantly  in  these 
localities  are  trained  so  as  to  make  a  thick  mass  of  young 
greenery  on  the  roof,  and  the  soil  is  lightly  strewn  with 
bark,  dead  sticks  or  leaves.  At  regular  intervals  of  a 
week  or  ten  days  these  shelters  can  be  visited  and  all 
pupae  easily  collected  by  boys  searching  in  the  sand. 

Should  the  method  prove  feasible  as  a  means  of  destruc- 
tion on  a  large  scale,  it  might  be  possible  to  put  sieves 
or  f)erforated  trays  in  the  sand  under  the  shelter  of  a 
kind  that  would  allow  the  pupae  to  be  quickly  sifted 
out.  Or  another  method  might  be  tried  of  destroying 
the  pupae  by  the  sun's  heat.  The  roof  could  be  made  in 
two  halves,  and  at  regular  periods  one  half  could  be  lifted 
off  so  that  the  pupae  beneath  would  be  killed  by  prolonged 
exposure  to  the  sun's  heat,  while  next  time  that  half 
would  remain  covered  and  the  other  half  be  taken  off. 
The  rainy  season,  however,  would  introduce  complica- 
tions into  this  method,  for  often  there  are  days  with  very 
little  sun,  and  if  the  sand  was  allowed  to  get  wet,  the 
flies  would  no  longer  deposit  pupae  therein.  The  method 
is  a  simple  and  inexpensive  one,  and  should  at  least 
greatly  reduce  the  numbers  of  the  fly.  There  is  no  doubt 
whatever  that  these  shelters  are  very  attractive,  and 
approved  of  by  the  fly  as  suitable  for  their  young.  Be- 
fore I  came  away  from  the  islands  in  1919  for  leave,  a 
number  of  artificial  breeding  grounds  were  prepared 
on  Bulago  and  Kimmi  and  are  now  being  tested.  The 
pupae  are  collected  weekly  from  each,  and  also  from  an 
ideal  natural  breeding  ground  on  each  island  for  com- 
parison, that  on  Kimmi  being  the  upturned  tree  roots  as 
described.  From  figures  that  have  reached  me  so '  far, 
it  is  clear  that  my  artificial  shelters  are  just  as  attractive 
as,  or  sometimes  more  than,  the  natural  shelters,  for  on 
some  occasions  not  so  many  pupae  are  found  under  the 
tree  as  under  one  of  the  shelters  close  by.  During  July 
over  two  thousand  pupae  were  destroyed  on  Kimmi  by 
this  method,  Kimmi  being  barely  a  mile  in  diameter. 


PROPOSED   NEW   METHOD    OF   DESTRUCTION  65 

Seeing  that  the  fly  is  such  an  abnormally  slow  breeder, 
and  that  this  method  destroys  generations  yet  to  come, 
it  does  seem  possible  that  it  will  result  in  very  substantial 
reduction  in  the  number  of  flies.  Of  course  a  few  pupae 
will  continue  to  be  placed  in  other  spots,  scattered  "  loci," 
but  with  the  reduction  in  number  of  flies  the  number 
of  these  would  be  reduced  in  far  greater  proportion, 
until  when  there  are  only  very  few  flies  about  it  seems 
reasonable  to  suppose  that  the  number  of  pupae  not 
deposited  in  the  shelters  would  be  so  small  that  the  fly 
would  be  exterminated  altogether.  This  would  probably 
take  some  years,  but  the  decline  would  be  a  steady 
one. 

The  method  could  be  made  applicable  to  Glossina 
morsitans  also,  only  in  this  case  the  shelters  would  need 
to  be  placed  not  near  the  water,  but  near  some  well 
marked  game  track  ;  for  morsitans  seems  to  place  its 
pupae  naturally  near  game  tracks. 

This  chapter  on  the  Tse-tse  fly  may  fittingly  be  con- 
cluded with  the  following  verses  : 

TO    GLOSSINA  :   A   CURSE  ! 

Thou  dipterovis  hexapod  (by  which  I  mean 

Thou  six-legged  creature  borne  on  pinions  twain), 

Thou  tracheate  arthropod, — in  short,  thou  FLY, 

With  buzz  importunate  arousing  my 

Just  wrath  ;   may  fiends  innumerable  rend 

Thy  quivering  form  in  twain,  and,  ruthless,  send 

Its  disunited  fragments  to  the  place 

Whex'e  bad  flies  go,  whate'er  their  name  or  race  ! 

May  my  sanguineous  fluid,  y'clept  blood,  . 

Which  thou  desirest  to  extract  for  food. 

Plunging  thy  sharp  proboscis  through  my  skin 

To  reach  capillaries  enshrined  within, 

Flow  freely  till  thou  burstest  ! 

Or,  again. 
Lest  this  should  cause  thee  insufficient  pain, 
May  justice  serve  to  thee  another  fate 
That  red  corpuscles  ne'er  cqrpusculate 
In  thj-  capacious  proventriculus, 
So  that,  attenuate,  ridicvilous, 
6 


CG    NATURAL  HISTORY  OF   GLOSSINA  PALPALIS 

Thou'i't  gnawed  to  death  by  cruel  starvation's  fangs  ! 

Yet  do  I  wish  for  thee  severer  pangs 

Since  none  of  the  above  are  adequate 

Or  quite  sufficient  to  express  my  hate  ! 

May  Bembex  wasps  (those  skilful  hunters)  thrust 

Into  thy  side  the  lancets  which,  I  trust. 

Will  fail  to  paralyse  thy  sense  of  pain 

While  rendering  thee   inert,    that   sod,   in  vain 

Thou  strivest  to  escape  from  htmgry  jaws 

Of  Bembex'  child,  devouring  without  pause 

Thy  non-essential  tissues  ;   till,  at  length 

When  it  shall  have  attained  its  perfect  strength. 

Thy  shrinking  vitals  are  devoured  by  it. 

And  there  is  left  of  thee  no  little  bit 

AVhereof  a  man  might  say,  ''  This  was  a  FLY, 

A  noble  creature  that  knew  how  to  die  "  ! 

So  that  there  shall  not  e'en  be  left  of  thee  , 

So  vain  a  thing  as  a  fond  memory  ! 

Thus  would  I  wreak  my  vengeance  on  thee,  pest. 
That  oft  hath  bitten  me  with  fiendish  zest  ! 


Addendum. 

The  first  observations  on  the  use  of  artificial  breeding 
places  were  made  in  1914,  but  were  interrupted  by  the 
war. 

During  the  war  my  friend,  Dr.  W.  A.  Lamborn,  in 
Nyasaland,  unknown  to  me,  was  experimenting  on  his 
own  lines  by  cutting  down  trees  to  make  artificial  breeding 
I)laces  for  G.  morsitans.  (See  Bulletin  of  Entomological 
Research,  May,  1916,  VII,  p.  38.)  This  method  had  been 
developed  by  him  independently,  for  my  re]3ort,  delayed 
in  publication  by  the  war,  was  not  pubhshed  until  1919. 
(See  Reports  of  the  Sleeping  Sickness  Commission  of  the 
Royal  Society,  1919,  No.  XVII,  pp.  67-71.)  I  did  not 
hear  of  Dr.  Lamborn' s  work  until  after  I  had  been 
able  to  develop  and  make  first  use  of  my  scheme  early 
in   1919. 


CHAPTER   IV 

THE    LAKE 

Some  facts  as  to  the  great  Lake  Victoria  will  probably 
be  found  of  interest  before  reading  a  general  account  of 
the  scenery  and  life  thereon. 

The  following  data  are  taken  from  the  eleventh  edition 
of  the  Encyclopcedia  Britannica  : 

Lake  was  discovered  by  J.  H.  Speke  on  August  3,  1858  ;  the  Ripen  falls, 
the  only  outlet,  discovered  by  him  on  July  28,   1862. 

Area  over   26,000  square  miles,   only  exceeded  by   Lake   Superior. 

Greatest   length   from   north   to   south,    250   miles. 

Greatest   breadth,    200   miles. 

Coast  line  of  over  2,000  miles. 

Height  above  sea  level,  about  3,720  feet. 

Greatest  known  depth,  270  feet. 

Largest  islands — 

Ukerewe,  near   Muanza  on   south   coast,   whose   greatest   diameters 

are  25  X  12  miles. 
Buvuma,  in  the  Napoleon  Gulf  on  north  coast,  which  has  an  area 
of  160  sqviare  miles.     (The  Isle  of  Wight  has  147  square  miles.) 

The  Sesse  Archipelago  contains  62  islands,  of  which  42  were  inhabited. 

Area  drained  by  the  lake,  including  lake  itself,   92,210  square  miles. 

Rainfall  over  whole  area  averages  50  inches  yearly. 

Annual  rise  and  fall  from    1-3  feet  :    maximunri  height  in  July. 

By  far  the  greater  part  of  the  water  that  enters  is  lost  by  evaporation. 

The  largest  affluent  is  the  River  Kagera,  which  enters 
on  the  west  coast,  and  was  crossed  by  Speke  on  January 
16,  1862,  on  his  way  to  the  discovery  of  the  Ripon  falls. 

He  says  of  it  :  "  Once  over  I  looked  down  on  the  noble 
stream  with  considerable  pride.  About  eighty  yards 
broad,  it  was  sunk  down  a  considerable  depth  below  the 
surface  of  the  land,  like  a  huge  canal,  and  is  so  deep,  it 
could  not  be  poled  by  the  canoe-men  ;  while  it  runs  at  a 
velocity  of  from  three  to  four  knots  an  hour." 

This  fine  river,  reckoned  as  430  miles  long,  derives  its 
waters   ultimately  from   the   south-eastern  slopes  of   the 

67 


68  THE   LAKE 

Mfumbiro  range  north  of  Lake  Kivu,  and  from  the  country 
between  Lake  Kivu  and  the  north  end  of  Lake  Tanganyika, 

It  is  formed  by  the  union  of  several  other  rivers,  and 
at  first  flows  northwards  and  slightly  westwards  and  then 
turns  abruptly  eastwards,  to  flow  eventually  into  the 
lake  at  about  the  middle  of  the  western  shore,  a  little 
north  of  Bukoba.  It  is  of  considerable  geographical 
interest  that  whereas  the  main  affluent  of  the  Victoria 
Nyanja,  and  thus  the  chief  ultimate  source  of  the  Nile, 
arises  from  the  south-eastern  slopes  of  the  IVIfumbiro 
Mountains,  the  other  side  of  the  same  mountains  gives 
origin  to  streams  of  which  the  most  important  is  the 
Rutchuru,   flowing  into   Lake   Albert   Edward. 

From  this  lake  the  Semliki  river  flows  into  Lake  Albert, 
adding  its  waters  to  those  brought  from  Lake  Victoria 
by  the  first  part  of  the  Nile,  via  Lake  Kioga. 

So  a  very  large  part  of  the  waters  of  the  Nile  above 
Khartum  have  passed  through  Lake  Albert. 

The  numerous  islands  among  which  I  worked  vary 
much  in  size,  from  Bugalla  and  Kome  down  to  mere  rocks 
or  shoals  of  sand.  The  commonest  type  is  composed 
of  central  grassy  uplands  rising  a  few  hundred  feet,  with 
a  belt  of  forest  along  the  water  of  breadth  varying  accord- 
ing to  the  lie  of  the  land.  But  some  islands  have  practi- 
cally no  forest  growth  ;  thus,  Kiuwa  is  conspicuous  as 
being  merely  a  conical,  grass  clad  hill,  with  a  thin  fringe 
of  bushes  near  the  water.  On  the  other  hand,  Damba 
is  quite  flat  and  almost  entirely  covered  with  dense 
forest.  Wema  has  one  peculiarity ;  one  of  its  four 
hills  is  crowned  with  forest,  the  base  and  the  surrounding 
terrain  being  grass  clad.  On  the  largest  isles  there  is 
much  park-like  country  ;  that  is  to  say,  the  grass  land  is 
dotted  with  fine  trees,  or  clumps  of  small  trees  and  bush 
forming  copses,  and  the  grass  being  thin  and  only  knee 
high,  this  is  delightful  country  for  walking.  The  shores 
of  the  islands  vary  much  in  appearance,  but  are  rarely 


THE    KAGERA    RIVER   AT    KIFU.MBIKO   (KYAKA    KORT),    ABOUT 
FORTY   MILES    FROM    THE    LAKE. 


THE    HEAD    OF    NAPOLEOV   GULF   WHERE   THE    NILE    ARISES    FROM    THE    LAKE. 
To  the  left  of  the  tree  a  faint  haze  indicates  the  site  of  the  Ripon  falls. 

To  face  p.  68  (tirst  pag 


THE    EASTERN    CATARACT    OF   THE    RIPON    FALLS    IN    I9IO. 


THE   BIRTH    OF   THE   NILE. 

Ripon  Falls  from  below. 


To  face  p.  68  (second  page)- 


SCENERY  69 

anything  but  beautiful.  The  most  picturesque  scenery- 
is  the  narrow  channel  between  two  islands  where  the 
blue  water  is  bounded  on  each  side  by  dense  vegetation  ; 
for  example,  the  lovely  passage  between  Damba  and  Kome, 
only  a  few  hundred  yards  wide. 

Forest  lies  on  either  side,  and  in  front  a  narrow  belt 
of  bright  green  papyrus,  growing  at  the  water's  edge. 
A  belt  of  reeds  springs  from  the  slightly  deeper  water, 
and  in  front  of  this  again  the  still  blue  surface  is  carpeted 
with  leaves  of  water-lilies,  whose  blue  or  pink  flowers 
stand  up  a  little  out  of  the  water. 

An  open  shore,  with  beach  of  finest  white  sand  or 
pebbles,  is  not  uncommon,  with  a  forest  belt  terminating 
abruptly  som^e  yards  away  from  the  water.  Here  there 
is  always  evidence  of  the  subsidence  of  the  lake  level 
in  the  shape  of  raised  beaches  at  the  edge  of  the  forest. 
Such  a  strip  of  shore  is  termed  a  "  fly  beach,"  since  it 
provides  ideal  conditions  of  food  and  shelter  for  the 
Tse-tse. 

In  some  places  the  shore  is  formed  of  bare  rock  of  a 
spongy  texture  and  red  brown  in  colour,  shelving  gently 
into  the  water,  or  sometimes  forming  small  cliffs.  Here 
and  there  a  stream  of  lava  makes  a  strip  of  lighter  colour, 
embedded  in  which  are  fragments  of  quite  different 
rock,  like  plums  in  a  duff. 

A  sm-all  headland  on  which  was  pitched  my  camp  on 
Damba  ended  in  a  face  of  grey  rock  perhaps  20  feet 
high,  in  which  was  a  crevice  filled  with  water- worn 
pebbles  at  least  12  feet  above  the  present  highest  level 
of  the  lake,  showing  how  the  water  had  receded. 

On  a  flat  rocky  coastline  the  forest  often  comes  quite 
to  the  water's  edge,  the  trees  actually  overhanging  the 
water,  and  there  are  usually  abundant  ferns.  Long 
stretches  of  very  low  lying  marshy  shore  are  common, 
and  are  more  or  less  under  water  during  the  high  level 
of  the  lake  in  the  heavy  rains.     Lush    grass  and  reeds 


70  THE  LAKE 

make  these  spots  very  attractive  to  hippos,  and  the 
soft  soil  is  churned  up  along  their  regular  tracks.  A 
very  curious  plant  flourishes  here,  for  all  the  world  like 
a  small  lettuce  floating  on  top  of  the  water.  It  propagates 
very  rapidly,  probably  by  budding,  so  that  many  square 
yards  of  water  may  be  covered  by  it,  and  patches  often 
are  driven  out  to  sea  by  a  land  breeze.  The  curious 
ambatch  tree,  with  its  short  thick  trunk  of  extraordinarily 
light,  pithy  wood,  scanty  leaves  and  j^ellow  papilionace- 
ous flowers,  flourishes  on  marshy  shores,  and  the  graceful, 
tall,  smooth  "  Makindu  "  (wild  date)  palm  is  plentiful. 
Only  one  other  species  of  palm  is  met  with  on  the  islands, 
a  species  called  "  Ekibo  "  by  the  natives,  having  a  short 
stem  and  very  large  dark  green  leaves,  whose  mid-ribs 
are  often  used  as  rafters  for  houses,  or,  when  young, 
furnish  the  fibre  used  in  sewing  the  planks  of  the  canoes. 
On  low  lying  sandy  or  muddy  shores  a  species  of  cane 
growing  to  a  height  of  10  feet  sometimes  forms  thickets 
very  unpleasant  for  one  to  penetrate  owing  to  the  sharp 
points  of  the  narrow,  hard  leaves.  Several  bushes  are 
very  characteristic  of  the  lake  shore  ;  one  ^  is  known  to 
the  Baganda  as  "  Oluzibaziba,"  and  forms  dense  thickets  ; 
it  has  leaves  very  much  like  those  of  a  poplar  in  shape 
and  setting,  which  are  the  favourite  food  of  the  Situtunga 
antelope.  Another,  called  "  Kinsambwe,"  has  harsh, 
hairy  leaves,  with  rather  a  rank  odour  ;  and  a  third, ^ 
with  leaves  much  like  ambatch,  was  called  by  the  natives 
"  Omuvuvumye."  Several  flowering  plants  sometimes 
made  patches  of  colour  ;  one  like  a  small  herbaceous 
sunflower  grows  in  banks  of  bright  yellow  ;  another 
(Ipomaea)  rambles  over  bushes  and  spreads  wide  its  purple 
convolvulus-like  flowers,  while  a  third,  called  "  Anyam- 
berege  "  by  the  natives,  sends  up  tall  shoots  on  which  grow 
flowers  much  reminding  one  of  single  hollyhocks  ;  bright 
yellow,    with   a   velvety   patch   of   purple   brown   at   the 

1  Euphorbiacpae ,  Alchornea  chordnta.  ^  PapiUonaceae. 


YOUNG    RAPHIA    PALM    ("  KIBO  ")   ON   THE    RIDGE   OF    KIRUGU    ISLE. 


WILD    DATE    PALM    ON    DAMBA    ISLE. 


To  face  p.  70  (first  page). 


A    TAXGLEI.i    MASS    OF    IPOMAEA    IN     FLOWER. 


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A    lJi:U    UF    BRACKEN"    ON    1;Ul;ALLA    in     IKONI     OF     I  HE    FuREriT    LEL I . 

To  face  p.  70  (second  page). 


VEGETATION  71 

base  of  each  petal.  One  other  characteristic  plant  may 
here  be  noted,  known  to  the  natives  as  "  E'tungulu  "  i 
It  grows  in  dense  patches,  throwing  up  straight  green 
stems  as  much  as  8  feet  high,  furnished  with  alternating 
leaves  of  very  thin  texture,  with  a  smooth  shiny  surface, 
bright  green  in  colour,  elongated,  and  with  pointed  tip^ 
The  flowers  are  borne  on  short  stalks  coming  up  separately 
from  the  leaf  stems  ;  they  are  in  shape  somewhat  like 
that  of  a  pentstemon,  in  colour  whitish  or  dull  pink 
according  to  the  species.  The  fruits  are  pear  shaped, 
attached  by  their  broad  bases  in  a  cluster,  and  are  of  a 
very  bright  shiny  red.  If  the  tough  skin  is  torn  open 
the  interior  is  found  to  consist  of  a  large  number  of 
round  black  seeds  embedded  in  a  white  pulp  with  delicious 
acid  taste  ;  hence  these  fruits  are  much  esteemed  by 
the  natives,  and  by  monkeys.  The  fruit  of  the  white 
flowered  species  is  poor  compared  to  that  from  the  red 
flowers. 

To  return  to  the  forest  belt.  A  characteristic  feature 
of  its  landward  side  is  the  abrupt  maigin  ;  one  suddenly 
emerges  from  forest  to  open  grass  land  as  though  the  edge 
had  been  cut  by  a  landscape  gardener. 

It  is. possible  that  this  edge  owes  its  origin  to  former 
systematic  burning  of  the  grass  by  natives,  so  that  no 
outlying,  straggling  fringes  survived.  Now  that  the 
population  is  no  longer  there,  however,  the  forest  edge 
seems  in  places  to  be  gradually  advancing  over  the  grass, 
the  vanguard  formed  by  rambling  bushes  of  low  growth. 
The  significance  of  this  had  not  occurred  to  me  until 
Fiske  pointed  it  out  in  1914. 

On  the  smaller  islets,  if  very  rocky,  the  only  trees  are 
figs,  which  seem  especially  to  thrive  close  to  the  water, 
and  may  sometimes  be  seen  perched  on  a  rock,  which  their 
descending  roots  embrace  on  all  sides.  These  doubtless 
owe  their  origin  to  seeds  dropped  by  some  pigeon. 

^  Anonaceae. 


72  THE   LAKE 

Owing  to  the  moist  climate  the  foliage  is  alv/ays  green, 
and  at  no  time  are  the  trees  as  a  whole  bare  of  leaves  : 
it  is  quite  common  to  see  one  tree  shedding  all  its  leaves 
while  another  near  by  is  in  the  full  glory  of  new  foliage. 

Flowers  on  the  islands  are  disappointing  ;  they  do  not 
enter  into  the  landscape,  but  there  are  many  creepers 
which  ramble  over  the  tops  of  the  forest  trees  and  are 
covered  with  sweet  scented  white  or  yellow  flowers  : 
many  trees  and  shrubs  also  have  fragrant  blossom.s, 
some  of  which  are  beautiful,  often  of  waxy  appearance. 

The  colouration  in  the  bright  sunlight  during  one  of 
the  clear  days  characteristic  of  the  heavy  rains  is  really 
wonderful  in  its  brilliancy.  From  high  ground  one 
looks  over  the  top  of  vividly  green  forest  towards  distant 
purple  islands  set  in  a  sparkling  deep  blue  lake,  which 
is  stirred  into  white -capped  waves  by  the  prevailing 
south-east  breeze.  So  clear  is  the  atmosphere  at  this 
time,  especially  in  the  evenings,  that  from  Bugalla  Island 
some  of  the  individual  houses  at  Entebbe  on  the  main- 
land, twenty-five  miles  away,  could  be  distinguished  with 
the  naked  eye,  and  the  flagstaff  at  Government  House 
could  be  seen  with  glasses,  though  I  could  never  make 
out  the  flag  itself. 

The  climate  of  the  islands  is  more  equable  than  at 
Entebbe,  the  water  exercising  its  usual  influence. 
Consequently,  although  the  average  mean  temperature 
is  degrees  higher  than  at  Entebbe,  the  maximum  is 
lower,  and  the  nights  warmer.  The  rainfall  also  is  more 
equably  distributed  than  on  the  mainland,  although  it 
is  greater.  There  was  no  month  without  some  rain  during 
the  twelve  of  which  I  kept  meteorological  records  on 
Bugalla,  but  the  greatest  fall  came  at  the  same  two 
periods  as  on  the  mainland.     (See  Chart  I.) 

A  striking  feature  is  that,  with  extremely  rare  excep- 
tions, the  rain  falls  between  midnight  and  noon,  often 
between  midnight  and  daybreak,  so  that  afternoon  rain 


ABRUPT    MARGIN    OF    FOREST    BELT   ON    BUGALLA. 
A  flowering  bush  of  Haionga  at  the  angle  was  much  frequented  by  butterflies. 


v.:  'rSMblsidisai 


\\\)   ON    BUGALLA    ISLE. 


To  face  p.  72. 


A   THUNDERSTORM  73 

which  occurs  at  Kampala  on  the  mainland,  a  few  miles 
from  the  lake  shore,  was  unknown  during  my  time  on  the 
islands.  Another  characteristic  is  that  the  rain  is  nearly 
always  accompanied  by  thunder  ;  but  though  this  is  so 
frequent  one  never  experiences  the  oppressive  heaviness 
of  atmosphere  which  precedes  a  thunderstorm  in  England. 
The  following  is  a  description  of  a  typical,  or  as  I  used 
to  call  it  a  formal,  thunderstorm,  such  as  occurs  with 
varying  intensity  every  few  days  from  mid-March  to 
mid- June  during  the  period  of  heaviest  rains.  The  day 
has  been  brilliantly  fine,  with  a  hard  blue  horizon  and 
vivid  colouring,  and  an  appearance  of  nearness  of  distant 
objects.  There  has  been  a  steady  breeze  all  day  long, 
dying  away  towards  sunset,  which  has  perhaps  shown 
for  a  brief  spell  a  glory  of  flame-tinted  cloudlets.  After 
dark  not  a  cloud  is  to  be  seen  anywhere,  and  the  stars 
shine  brilliantly.  Before  turning  in  at  about  8' 30  one 
takes  a  look  round,  but  there  is  nothing  to  note  except 
a  distant  flickering  of  lightning  to  the  south-east,  which 
is  practically  a  nightly  occurrence  in  the  rainy  season. 

Having  seen  that  tent  pegs  and  ropes  are  secure,  and 
that  the  front  of  the  tent  can  be  quickly  closed  in  an 
emergency,  for  these  storms  often  give  one  little  time, 
one  turns  in,  to  be  not  at  all  surprised  at  being  awakened 
in  the  small  hours,  usually  between  two  and  three, 
by  a  rumbling  of  thunder.  Stepping  outside  the  tent 
one  sees  magnificent  piled  up  masses  of  inky  cumuli 
illum.inated  by  almost  incessant  flickerings  of  lightning. 
Sometimes  a  flash  stretching  in  an  arc  right  across  the 
heavens  makes  one  start  with  the  wonder  and,  almost, 
fear  of  it. 

In  the  momentary  intervals  between  the  rumblings  of 
thunder  can  be  heard  a  faint  musical  sound,  produced 
by  the  downpour  of  rain  on  the  water,  as  yet  far  away. 
There  is  nothing  to  be  done  but  to  make  sure  that  the 
tent  is  firmly  secured,  fasten  up  the  door,  enduring  an 


74  THE   LAKE 

"  infinite  torment  "  of  mosquitoes  which,   aware  of  the 
coming  storm,  have  thronged  into  the  tent  for  shelter, 
and  retire  to  bed  again  to  await  the  onward  march  of  the 
storm,  for  no  more  sleep  is  possible  until  it  has  passed. 
Overhead  the  stars  are  still  shining  brilliantly,  and  it  is 
absolutely  calm.     Presently  a  faint  murmuring  of  wavelets 
is   heard  ;     heralds  of  the  disturbance  produced  by  the 
distant  storm,  by  the  time  they  reach  the  island  reduced 
to  mere  ripples.     Now  a  faint  breath  of  wind  can  be  felt, 
which  dies  away,  followed  by  another  puff,  and  the  sound 
of  the  rain  and  thunder  grows  louder,  while  the  light- 
ning  increases   in   intensity   until   it   almost   hurts   one's 
eyes,  kept  tightly  shut.     The  ripples  increase  into  waves, 
and  the  noise  of  surf  on  the  beach  is  added  to  the  distant 
sounds.     A  few  fat  drops  of  rain  descend,  and  then  with 
a  rush   and  a   roar  the  storm   arrives.     A  hurricane  of 
wind  tears  and  shakes  the  tent  until  one  expects  every 
minute  to  be  carried  away  with  it ;  the  roar  of  the  sheets 
of  rain  on  the  roof  is  almost  loud  enough  to  drown  the 
deafening  thunder  produced  by  flashes  of  lightning  that 
seem  to  split  one's  very  head  in  twain.     This  pandemonium 
lasts  for  about  a  quarter  of  an  hour,  when  the  wind  moder- 
ates  a  little,   the    rain    increases    in   intensity,   and    the 
thunder  gradually  passes  away  as  the  centre  of  the  storm 
moves  off.     After  an  hour  or  so  the  rain  slackens,  but 
continues    very    heavily    until    shortly    before    daybreak, 
though  sometimes  continuing  steadily  until  the  morning 
is    well    advanced  ;     the    evening    being    again    line    and 
clear.     In    one    such   storm    two    and   a   half    inches    of 
rain   fell   between   6.30   and   9   a.m.     Such  is  the  formal 
storm    of    the    wet    season,    but   quite   frequently   there 
are   dry   thunderstorms,  when    the   lightning   apparently 
discharges    from    one    cloud    to    another,    and    there    is 
no  rain.     The  thunder  on  these  occasions  has  a  hollow, 
light   quality,   probably   due   to   the   rarified   air   of    the 
upper  regions  in   which    the    storm   occurs.     The  clouds 


CLOUDS  75 

are  greatly  disturbed,  and  one  seems  to  be  looking  upwards 
into  a  vortex.  There  is  usually  a  central  area  to  which 
ragged  pieces  of  cloud  drift  from  all  directions,  only  to 
be  torn  into  shreds  and  vanish  as  if  they  had  gone  up  a 
chimney.  These  overhead  disturbances  may  be  accom- 
panied by  no  disturbance  whatever  at  earth  level,  where 
the  sun  shines  and  a  fine  weather  breeze  blows  as  usual. 
Sometimes  the  edges  of  the  clouds  at  the  centre  of  these 
storms  may  be  wonderfully  rainbow  tinted,  although  no 
rain  reaches  earth.  On  Damba  Island  in  June  1911  was 
seen  one  evening  a  wonderful  cloudscape  to  the  East. 
Low  down,  over  the  mainland,  were  the  usual  lumpy 
cumuli,  and  to  the  right  these  merged  into  nimbus. 
Converging  to  a  point  on  the  horizon  between  these  were 
two  broad  filmy  streaks,  above  and  transverse  to  which 
were  bars  of  cirro-stratus.  This  cloud  complex  was  the 
forerunner  of  the  highest  wind  I  had  experienced  on  the 
islands  up  to  that  time  ;  it  began  at  midnight  and  re- 
peatedly awakened  me  :  by  mid-day  the  blue  lake  was 
whitened  with  curling  wave  crests,  and  drifting  purple 
and  green  cloud  shadows  made  lovely  contrasts  of  colour. 
Since  I  was  very  dependent  on  the  state  of  the  weather 
for  my  work  outdoors,  I  took  some  interest  in  the  signs, 
and  an  account  of  what  was  learnt  may  be  of  interest. 

Firstly,  the  meteorological  signs. 

There  were  the  usual  general  signs,  such  as  cirrus  or 
cirro-stratus  clouds  and  clearness  of  atmosphere,  heralding 
storms  ;  heat  haze  in  fine  weather,  etc. 

The  approach  of  the  rainy  season  is  preceded  by  cloud 
funnels,  which  appear  in  all  stages  from  a  nipple  shaped 
process  at  the  lower  edge  of  a  ragged  cloud,  to  a  complete 
pillar  connecting  cloud  and  lake,  called  by  the  natives 
"  Omusoke."  From  Entebbe,  looking  out  over  the 
lake,  a  great  number  of  these  are  seen,  and  they  are 
commonly  called  waterspouts,  but  I  have  never  been 
near  enough  to  make  out  whether  they  correspond  to 
waterspouts  at  sea. 


76  THE   LAKE 

There  is  a  great  deal  to  be  learnt  from  the  wind,  its 
direction  and  force,  and  so  on.  The  daily  wind  blows  from 
the  south-east,  being  strongest  in  early  afternoon  and 
dying  away  towards  sunset.  Sometimes  it  blew  so  strongly 
when  I  was  on  Damba  that  canoes  could  not  go  out  on 
account  of  the  white  capped  waves  and  the  surf  on  the 
shore.  If  this  wind  freshens  again  after  sunset  for  a 
little  while,  it  usually  implies  bad  weather  next  day, 
especially  if,  during  the  night,  a  few  fat  drops  of  rain  fall. 
Such  a  night  followed  by  a  very  calm,  clear,  warm,  clouded 
morning  at  daybreak  invariably  portends  a  storm  before 
mid-day,  and  one  would  not  think  of  going  out  in  a  canoe. 

On  the  contrary,  an  early  morning  cold  northerly  breeze 
from  the  mainland,  with  thick  haze,  foretells  a  very  fine 
hot  day.  This  north  breeze  blows  quite  violently  until 
8  or  9  a.m.,  when  it  suddenly  drops  ;  and,  as  suddenly, 
the  south-east  wind  rises  and  impresses  its  mark  on  the 
lake  before  the  waves  due  to  the  north  wind  have  subsided  ; 
so  that  one  sees  ripples  travelling  in  a  northerly  direction 
superimposed  on  the  swell  running  southwards.  During 
the  rainy  season,  when  there  is  a  calm,  curious  map- 
like areas  of  irregular  shape  and  varied  tints  appear  on 
the  still  water,  and  I  came  to  the  conclusion  that  they 
preceded  a  storm. 

Occasionally  during  this  time  of  year  the  sun  appears 
surrounded  by  a  misty  ring  at  a  considerable  distance 
from  it  ;  but  this  was  not  common,  and  I  never  was  able 
to  make  out  that  it  heralded  any  particular  type  of  weather. 

In  the  driest  months  at  the  end  of  one  year  and  com- 
mencement of  the  next  the  sun's  heat  is  powerful  enough 
to  cause  grass  to  take  light  spontaneously.  Fires  seen 
on  the  islands  are  usually  considered  to  be  evidence  of 
the  presence  of  natives  in  the  forbidden  area,  but  I  am 
quite  satisfied,  from  the  following  instance,  that  they 
can  be  of  "  spontaneous  "  origin 

On  January  29,  1919,  I  was  examining  Nyenda  Island, 


SPONTANEOUS   GRASS   FIRE  77 

my  camp  being  on  the  southern  side  of  Wema.  As  we 
returned  in  the  afternoon  the  grass  all  round  the  camp 
was  seen  to  be  burning,  and  I  found  when  I  got  back 
to  camp  that  it  had  had  a  narrow  escape.  The  boys 
said  that  about  2  p.m.,  while  in  their  houses,' they  had 
heard  a  sound  like  a  gun-shot,  and  going  out,  saw  a 
cloud  of  smoke  arising  to  windward,  and  heard  flames 
crackling.  They  only  just  had  time  enough  to  strike  the 
tent  and  get  my  things  further  away  from  the  edge  of  the 
long  grass,  and  had  there  not  been  a  space  cleared  for 
the  camp,  the  huts  would  all  have  been  burnt. 

They  showed  me  afterwards  the  spot  where  the  fire 
had  commenced.  Among  much  bare  red  rock  there  was 
thin  dry  grass  on  light  soil,  and  at  one  place  was  a  hole 
looking  as  if  the  earth  had  fallen  in  over  a  termite's 
burrow.  Here  was  an  appearance  that  suggested  that  a 
quantity  of  dry  debris  lying  at  the  bottom  of  the  open  pit 
had  suddenly  taken  fire  with  explosive  violence,  for  the 
edges  of  the  hole  had  obviously  just  been  disturbed. 

Such  fires  are  well  known  to  the  natives,  who  call  one 
"  Nakibengeyi  "  ;  they  pointed  out  the  red  rock  to  me 
as  a  kind  that  is  particularly  associated  with  these 
spontaneous  fires.  It  is  of  a  spongy  texture,  apparently 
of  igneous  origin,  and  certainly  does  absorb  and  radiate 
a  great  amount  of  heat  from  the  sun. 

The  signs  of  weather  afforded  by  the  island  life  are 
abundant,  and  doubtless  many  more  than  here  recorded. 
Several  birds  give  useful  indications.  A  curious  booming, 
hollow  sound  is  sometimes  heard  during  the  rainy  season 
preceding  a  storm,  and  it  was  a  long  while  before  I  finally 
satisfied  myself  that  it  emanated  from  the  crowned 
crane.  The  natives  insisted  that  it  was  produced  by  the 
puff  adder ! 

The  large  black  and  white  hornbill  is  always  much 
more  vociferous  on  one  of  the  clear  blue  evenings  before 
rain,  and  gulls  on  the  rocks  scream  and  chatter  much 


78  THE   LAKE 

more  vigorously.  When  terns  appear  off  the  coasts  of 
islands,  one  knows  that  windy  weather  is  coming,  for 
under  other  conditions  they  were  never  seen  ;  presumably 
they  then  frequent  the  open  lake. 

The  glorious  fish  eagle  is  much  more  vociferous,  accord- 
ing to  the  natives,  when  the  wind  is  rough,  but  I  never 
satisfied  myself  of  this,  and  think  he  screams  more  on 
account  of  brilliantly  fine  weather,  which,  of  course,  is 
often  accompanied  by  a  fresh  breeze.  One  of  the  large, 
pale  blue,  insectivorous  kingfishers,  which  haunts  thick 
bush  or  forest,  utters  his  characteristic  cheerful  cry  with 
greater  persistence  when  the  early  morning  is  particularly 
fine  and  brilliant.  A  species  of  woodpecker,  like  the 
"  yaffle  "  at  home,  is  only  heard  to  cry  before  rain. 

Frogs,  .  of  course,  croak  before  rain,  especially  one 
species  which  inhabits  burrows  in  the  earth  ;  indeed, 
it  is  never  heard  to  croak  except  in  the  evening,  before 
rain,  unless  it  is  breeding.  The  green  tree-frog,  so 
abundant  on  herbage  of  the  lake  shore,  sends  forth  its 
high-pitched,  scraping  note  when  it  thinks  there  is 
rain  about. 

I  had  an  amusing  experience  one  day  on  the  shore. 
It  was  about  noon  on  a  very  fine  day  ;  a  small  cumulus 
cloud  slowly  formed  and  emitted  a  single  crack  of  thunder 
without  in  any  way  dimming  the  brightness  of  the  day. 
This  clap  of  thunder  was  immediately  followed  by  a  chorus 
of  satisfied  quackings  from  a  host  of  concealed  frogs, 
sounding  ridiculously  like  applause  of  a  well-meant  effort ! 
There  was  no  rain,  however,  so  the  prophets  were 
forsworn. 

Fish  also  afford  signs  for  a  weather  prophet  to  interpret. 
Thus,  in  my  journal  for  January  30,  1914,  is  noted : 
"  Off  the  south-west  point  of  Ngamba  Island  little  fish 
were  leaping  about  in  the  water  and  also  in  shore,  close 
under  the  bushes.  About  a  hundred  yards  away  from  the 
island  the  glassy  surface  of  the  water  was  broken  by  a 


AERIAL    ROOTS    DH'I'ING    TO    GROUND,    BUGALLA    FOREST. 


GIANT   TWISTED    STEM    OF    CREEPER,    BUGALLA    FOREST. 


To  face  p.  78. 


WEATHER   PROPHETS  70 

collection  of  the  '  male  '  fish  (see  Chapter  IX,  ]).  193) 
tumbling  and  wriggling  about.  The  natives  said  they 
were  mating."  The  next  day  was  noted  as  "  a  beastly 
cold,  stormy  day,  with  black  clouds,  after  a  lot  of  thunder 
and  rain  at  1  a.m."  On  Feburary  21st  the  same  occur- 
rence was  seen  off  Wema  Island  ;  the  small  fish  hopping 
out  of  the  water,  and  male  tumbling  about.  The 
following  day,  however,  was  also  fine  and  hot,  and  rain 
did  not  come  until  the  twenty-third. 

I  think  this  behaviour  of  the  fish  is  not  of  any  immediate 
significance,  but  occurs  just  before  the  rains  commence 
in  earnest,  in  March. 

It  was  again  noticed  very  often  when  voyaging  in 
January  and  February  1919  ;  sometimes  the  canoe 
would  be  so  close  that  the  men  could  almost  have  netted 
the  fish. 

Insects,  as  might  be  expected,  furnish  many  signs  of 
coming  rain. 

The  most  obvious  is  the  appearance  of  immense  numbers 
of  a  non-biting  gnat,  of  the  family  Chironomidae,  called 
by  the  natives  "  E'sami  "  (pronounced  Sammee).  They 
appear  as  brown  clouds  drifting  over  the  lake,  along  the 
horizon,  like  smoke  from  a  distant  steamer.  Eventually 
they  are  blown  ashore,  where  they  seek  shelter  among 
trees.  These  clouds  are  most  often  seen  just  before 
and  during  the  heavy  rains.  If  Sami  happen  to  arrive 
at  one's  camp  after  dark  they  swarm  around  the  lamp  and 
drive  one  nearly  desperate.  Other  insects  also  come  to 
the  lamp  before  rain,  particularly  Ephemeridae  of  different 
sizes.  One,  about  the  size  of  the  common  English  "  may- 
fly," once  came  to  the  camp  fire  in  such  numbers,  anS 
their  burnt  bodies  made  such  an  appalling  stench,  that 
it  was  too  much  even  for  the  natives,  who  put  out  the 
fire  and  retreated  !  A  smaller,  paler  species  has  the 
extremely  annoying  habit  of  alighting  upside  down  on 
one's  table  or  writing  paper,  and  flopping  miserably  about 


80  THE  LAKE 

until  he  dies  !  Other  still  smaller  species  of  two-winged 
flies  have  an  extraordinary  liking  for  singing  their  high- 
pitched  song  inside  one's  ears,  until  one  can  bear  it  no 
longer  and  retires  beneath  the  mosquito  net. 

To  these  nuisances  may  be  added  an  enormous  male 
ant  {Dorylus)  with  shiny,  hard,  light  brown  body  over  an 
inch  long,  who  bangs  himself  against  the  lamp,  and  returns 
however  often  he  be  thrown  outside  with  contumely, 
until  one  is  forced  to  go  against  one's  scruples,  and  bottle 
him.  I  have  dispatched  as  many  as  twenty  on  one  evening. 
They  are  a  very  reliable  sign  of  coming  rain  if  they  are 
seen  in  any  number  :  the  workers  also  are  much  more 
often  seen  on  the  march  before  rainy  weather.  Termites, 
likewise,  are  much  more  harmful  in  wet  weather,  and 
cover  the  timbers  of  one's  house  with  earth  with  sur- 
prising rapidity  at  such  times. 

The  biting  flies  known  as  "  buffalo  gnats  "  (Simulium) 
are  especially  eager  to  bite  in  the  early  morning  or  evening 
before  rain  on  the  islands.  Thus  on  July  26,  1914, 
on  Kome  Island,  is  noted  in  my  journal :  "  I  went  down 
to  the  rocky  shore  before  breakfast,  and  was  set  upon  by 
a  swarm  of  viciously  biting  Simulium.  In  the  evening 
many  Ephemeridae  came  to  the  lamp."  Next  morning, 
after  daybreak,  there  was  the  worst  thunderstorm  I 
had  ever  experienced  on  Kome. 

The  night  time  on  the  islands,  apart  from  thunder- 
storms, has  charms  of  its  own,  A  number  of  sounds 
are  to  be  heard  from  sunset  until  the  small  hours,  when 
for  a  while  there  is  silence  until  the  first  glimmerings  of 
dawn.  The  thunderous  snortings  of  hippos,  the  muffled 
bark  of  the  Situtunga,  break  in  upon  the  continuous  shrill 
tinkling  sound,  curiously  suggesting  sleigh  bells,  produced 
by  thousands  of  small  frogs  along  the  shore.  Crickets 
chirp  all  round  and  in  the  house,  and  during  the  rains  one 
enormous  species,  sitting  just  inside  the  mouth  of  its 
burrow,  makes  the  earth  resound  with  a  continuous  high- 


BIRD   SOUNDS  81 

pitched  buzzing  sound,  which  if  at  all  near  seems  to 
penetrate  through  and  through  one's  head,  and  renders 
sleep  impossible  until  the  performer  has  been  silenced. 

The  chattering  and  quarrelling  of  gulls  on  the  rocks 
mingles  with  the  plashing  of  wavelets  and  the  gaggling 
of  Egyptian  geese,  which  are  restless  at  night. 

Perhaps  there  passes  overhead  a  flight  of  some  kind  of 
plover,  whose  cry  has  earned  for  them  the  native  name 
"  Empunya,"  and  in  the  distance,  over  the  open  grass 
land,  a  hunting  owl  emits  its  drawn  out  quavering  call, 
and  a  nightjar  its  "  Tok-tok-tok-tok-tok  "  for  long  periods 
without  a  pause. 

Occasionally  an  ibis,  startled  by  something,  disturbs 
the  night  with  its  raucous  alarm  cry,  "  Aa-aa-aa,"  or  an 
awakened  monkey  in  the  forest  says  what  it  thinks  of 
the  disturber  before  settling  down  to  sleep  again. 

With  the  first  glimmerings  of  day  the  chorus  of  birds 
begins,  and  the  forest  resounds  with  their  cries  and  music, 
for  there  are  many  songsters  of  merit.  Soon  the  troops 
of  monkeys  awake  and  commence  their  hunting,  and  the 
loud  "  kubba-kubba  "  cry  shows  where  they  travel  among 
the  tree-tops  ;  and  for  the  rest  of  the  day  the  forest  is 
never  silent.  A  species  of  forest  francolin,  living  in  the 
densest  thickets,  has  a  loud  ringing,  laughing  cry  which, 
taken  up  by  one  after  the  other,  often  resounds  through 
the  forest  during  the  heat  of  the  day  when  other  birds 
are  relatively  quiet.  Towards  evening  the  hornbill 
waxes  vociferous,  and  his  "  Nga-nga  "  cry,  from  which 
he  gets  his  name,  seems  characteristic  of  that  time ; 
flocks  of  grey  parrots  flying  home  from  the  forest  shriek 
in  the  familiar  discordant  way,  and  snow  white  egrets 
sedately  wend  their  way  with  hoarse  croakings  across 
the  blue  water  to  their  accustomed  roosting  places.  The 
sunset  chorus  of  songsters  has  hardly  subsided  before 
the  frogs  and  crickets  take  up  the  strain,  and  with  the 
rising  of  the  moon  owls  add  their  melodious  cry. 

7 


82  THE  LAKE 

Life  on  the  islands  was  soon  reduced  to  a  routine  only- 
interfered  with  by  the  weather.  Arising  shortly  before 
the  sun  one  pottered  about  for  half  an  hour  before  a 
bath,  or  a  swim,  and  breakfast. 

At  eight  o'clock  one  set  off  for  the  fly  ground.  On 
Bugalla  this  simply  meant  a  walk  of  about  half  a  mile 
down  from  the  open  grass  clad  hill  on  which  camp  was 
placed,  through  the  forest  belt,  and  out  on  to  the  sandy 
beach. 

When  on  Damba  we  cut  across  a  shallow  bay  by  canoe 
to  the  beach  about  a  mile  away  ;  from  Kome  camp  we 
went  by  canoe  to  the  other  islets,  and  very  pleasant  going 
it  was  against  the  fresh  north  breeze  and  dancing  waves, 
taking  an  hour  or  more.  From  this  one  returned  at  any 
hour  between  2-5'30  p.m.,  after  which  there  was  a  certain 
amount  of  work  to  be  done  with  the  microscope. 

On  Bugalla  the  afternoon  was  always  spent  over  the 
microscope  ;  and  a  walk  over  the  highlands  in  the  evening 
gave  one  exercise  and  beautiful  views. 

Sundays  were  always  given  up  to  butterfly  hunting 
and  other  changes  of  occupation.  On  Saturdays  the  big 
canoe  with  crew  of  fourteen  men  started  off  for  Entebbe 
taking  mails,  returning  on  Tuesdays  or  Wednesdays 
according  to  weather,  with  mails  and  the  week's  supply 
of  food  for  those  of  us  who  always  remained  in  camp. 
Sometimes  this  canoe  had  very  rough  passages,  and  I 
well  remember  one  night  near  the  end  of  my  residence 
on  Bugalla.  It  was  one  of  the  exceptional  occasions  when 
there  was  a  storm  after  sunset  coming  from  the  north- 
east. The  crew  as  usual  had  announced  their  approach 
by  blowing  on  a  horn  of  the  Situtunga  antelope,  and  I 
was  rather  anxious,  as  a  storm  was  threatening  from  the 
same  direction. 

Gradually  the  wind  freshened  until  a  gale  was  blowing, 
and  the  house  rocked.  I  lit  a  lantern  and  went  down 
to  the  shore  to  mark  the  landing  place,  as  it  was  pitch 


AN  UNUSUAL   STORM  83 

dark.  Above  the  roar  of  the  surf  on  the  coast  could  be 
heard  the  shouts  of  the  paddlers  furiously  urging  on  the 
canoe  in  front  of  the  storm,  but  they  were  not  able  to  make 
the  shore  where  I  was  on  account  of  breakers.  By  great 
good  fortune  they  were  enabled  safely  to  round  a  headland 
and  land  in  comparative  calm.  Had  the  storm  been  from 
the  usual  south-east  direction,  they  could  not  have  faced 
it,  but  would  have  had  to  turn  and  run  before  it  ;  but 
these  early  night  storms  came  from  a  direction  different 
from  that  of  the  formal  storms  described  previously. 


CHAPTER  V 

CANOES    AND    A    VOYAGE 

Unless  one  is  very  fond  of  the  water  and  a  good  sailor, 
travelling  by  canoe  becomes  tedious  or  even  unpleasant. 
If  merely  a  passenger  one  sits  right  forward  in  the  bows 
and,  when  the  lake  is  anything  else  than  smooth,  very 
soon  gets  well  splashed.  I  always  took  the  steering 
paddle  and  found  it  great  fun  ;  a  good  deal  of  skill  is 
required  to  keep  a  heavy  canoe  true  to  its  course  when  a 
strong  beam  wind  persistently  blows  the  bows  round. 

The  canoe  ("  Eryato  ")  made  by  the  Basesse  is  of  a 
peculiarly  interesting  type,  since  in  the  first  place  it  forms 
a  link  between  a  "  dug-out  "  and  a  built  vessel,  and  in 
the  second  place  shows  how  the  keel  of  a  modern  boat 
represents  all  that  is  left  of  an  original  dug-out. ^  In  the 
old  days  of  warfare  on  the  lake  between  the  Basesse  of 
the  islands  and  the  Baganda  of  the  mainland,  these  canoes 
were  of  very  large  size,  and  I  have  heard  it  said  that  they 
could  accommodate  fifty  paddlers. 

The  most  important  part  is  the  keel  ("  Omugongo  "), 
which  is  hewn  from  a  tree  of  a  particular  species,  found 
by  experience  to  provide  the  best  wood  for  the  purpose. 
It  is  very  thick  and  solid,  with  a  rounded  bottom  and 
hollowed-out  upper  surface,  so  that  in  transverse  section 
it  is  concavo-convex  ;  it  is,  in  other  words,  a  "  dug- 
out." Seen  from  above,  it  is  broader  in  the  middle  than 
at  the  ends. 

^  Mr.  Henry  Balfour  pointed  this  out  when  I  gave  him  a  model  for 
the   Pitt   Rivers   collection   at   Oxford. 

84 


STRUCTURE    OF   A   CANOE  85 

The  after  end  is  ^shaped  so  that  the  stern  post 
("  Ekiwenda  ")  can  be  fitted  to  it,  and,  similarly,  a  stem 
post  is  fitted  near  to  tJie  forward  end  of  the  hollowed-out 
keel,  of  which  the  extreme  anterior  pointed  end  has  been 
left  solid,  to  project  beyond  the  stem  post. 

These  stem  and  stern  posts  are  inclined  forward  and 
aft  at  half  a  right  angle,  and  are  fastened  at  the  bottom 
to  the  keel,  whose  hollow  is  shaped  to  embrace  them 
slightly  by  palm  fibre  passed  through  holes  ("  Endagire  ") 
bored  with  a  hot  iron.  The  next  step  is  the  fitting  of  the 
lower  side  planks  ("  Amabasi "),  one  on  each  side,  stretching 
from  stem  post  to  stern  post,  and  secured  to  them  and  the 
keel  by  palm  fibre  {"  Ensinga  ").  These  planks  are  made 
from  wood  different  from  that  chosen  for  the  keel  ;  the 
latter  has  to  be  rigid,  but  a  measure  of  pliability  is  required 
for  the  planks.  The  upper  edge  of  the  lower  plank  is 
neatly  bevelled  off  to  fit  the  lower  edge  of  the  upper  plank 
("  Olwero  ").  This,  again  of  a  different  wood,  for  it  has 
to  stand  exjjosure  to  hot  sun  in  between  occasional  wetting 
by  waves  without  cracking,  is  made  of  three  pieces,  for 
it  has  to  take  a  considerable  curve.  The  main  piece  runs 
along  the  greater  length  of  the  canoe,  but  a  small  length 
("  Eryungo  ")  is  required  at  bow  and  stern  to  take  the 
curvature  from  the  end  of  the  main  piece  to  stem  or  stern 
post.  Where  these  pieces  overlap  they  are  neatly  fined 
down  so  that  the  thickness  of  the  two  is  no  greater  than 
the  thickness  of  a  single  piece.  At  the  extreme  ends, 
bow  and  stern,  the  pieces  of  opposite  sides  are  firmly 
pulled  together  by  stout  lashings  passing  across  and  across 
the  interior  of  the  canoe.  The  lines  of  junction 
("  Entabiro  ")  between  upper  and  lower  side  planks, 
and  lower  planks  and  keel,  are  covered  by  laths  of  wood 
cut  by  spHtting  sticks  longitudinally  ;  a  strip  ("  Olu- 
wamba ")  is  laid  with  flat  surface  next  the  junction, 
and  lashings  of  "  Ensinga  "  pass  through  the  planks  on 
each  side  of  It,  and  over  its  rounded  surface. 


86  CANOES  AND  A   VOYAGE 

These  strips  cover  the  lines  of  junction  on  inner  and 
outer  surfaces  of  the  canoe,  and  all  crevices  are  thoroughly 
plugged  with  fibrous  material. 

The  thwarts  ("  Amanga  ")  on  which  the  paddlers  sit 
are  fastened  in  a  peculiarly  ingenious  manner,  so  that  they 
also  serve  to  brace  the  sides. 

Each  rests  on  the  upper  margin  of  the  lower  side  plank, 
which  is  notched  to  receive  it,  as  is  also  the  lower  margin 
of  the  plank  above  ;  the  thwart  itself  is  grooved,  not 
quite  at  the  extremity,  so  that  its  actual  end  is  visible 
as  a  knob  ("  Empumi  ")  on  the  outside  of  the  canoe. 
The  grooves  in  the  thwart  and  notches  in  the  planks  all 
correspond,  so  that  everything  fits  as  closely  as  possible, 
and  leakage  is  prevented  by  plugging.  All  the  holes 
through  which  pass  the  fibres  fastening  the  planks  are 
tightly  plugged,  and  as  the  plugging  swells  in  the  water 
a  good  canoe  leaks  very  little,  although  no  resinous  or 
tarry  material  of  any  kind  is  used. 

A  peculiarity  of  these  canoes  is  that  right  forward  a 
long  spike  projects  out  from  each  side,  made  by  a  thwart 
("  E 'garni  ")  fitted  exactly  as  are  the  paddlers'  seats, 
with  which  it  is  serially  homologous  ;  but  its  outer  ends 
are  produced  into  spikes  instead  of  being  rounded  off 
into  mere  knobs.  This  projection  is  of  great  use  when  a 
heavy  canoe  has  to  be  hauled  up  on  the  shore,  but  I  do 
not  know  if  that  is  why  it  was  designed  in  the  first  place. 

Another  feature  is  the  upturned  prow  ("  Ensanda  "). 
It  was  said  that  the  part  of  the  keel  left  projecting  beyond 
the  stem  post  is  not  hollowed  out,  and  gradually  tapers 
off.  Over  this  is  fitted  one  arm  of  a  large  right-angled 
piece  of  wood,  whose  other  arm  therefore  projects 
upwards  into  the  air  for  two  or  three  feet,  and  several 
feet  forward  of  the  real  bow  of  the  canoe,  and  makes  an 
excellent  breakwater  against  waves.  The  projecting  keel 
gives  an  extra  lift  to  the  bow  of  the  canoe,  so  that  they 
are  excellent  sea  boats,  though  the  prominent  prow  and 


A   CANOE    RACE. 


A    HALT    ON   THE    EAST   COAST    OF    KUGALLA. 


To  face  p.  86. 


FITTINGS   OF  A   CANOE  87 

spikes  manage  to  distribute  a  good  deal  of  water  over 
any  one  in  the  bows,  unless  there  is  a  calm. 

On  top  of  the  "  Ensanda  "  is  placed  a  decorative  tuft 
of  feathers,  known  as  "  Enkuli,"  and  a  string  stretched 
between  it  and  the  top  of  the  stem  post  ("  Ekiwenda  ") 
has  a  series  of  plaits  dangling  from  it  vertically.  This 
ornament  is  called  "  Akasenso."  The  top  of  the  stern 
post  is  often  also  ornamented  with  a  tuft  of  grass 
("Engudi"). 

When  the  canoe  is  sufficiently  loaded,  the  ends  of 
the  thwarts  are  just  on  the  water  line.  The  paddles 
("  Enkasi  ")  are  quite  simply  made,  with  no  attempt  at 
decoration  ;  the  blade  is  broad  at  the  base  and  tapers 
to  a  point,  its  surfaces  not  being  absolutely  plane,  for  one 
side  ^s  very  slightly  concave,  the  other  equally  slightly 
convex.'  An  essential  part  of  the  equipment  of  a  canoe 
is  the  baler  ("  Olutiba "),  made  by  hollowing  out  a 
rectangular  block  of  wood  into  a  shallow  basin.  One  of 
the  crew  amidships  makes  it  his  business  to  free  the  canoe 
at  intervals  from  the  water  that  collects  in  the  hollow  of 
the  keel  ("  Ekyuwo  ")  ;  if  the  canoe  is  an  old  one  so  that 
the  edges  of  the  planks  and  keel  are  getting  soft,  it  cannot 
be  properly  plugged,  and  one  man  is  needed  to  bale  con- 
tinuously. 

After  two  or  three  years  the  wood  of  the  keel  rots  and 
the  planks  crack,  so  that  the  life  of  the  canoe  is  finished  ; 
the  natives  require  two  or  three  months  to  make  a  new 
one. 

With  a  good  crew,  each  accustomed  always  to  take  the 
same  thwart,  and  paddling  well  together  to  a  rhythmic 
song,  the  motion  is  very  pleasant,  and  considerable  speed 
is  attained.  Sometimes  each  man,  at  the  height  of  the 
stroke,  knocks  the  haft  of  his  paddle  against  the  side 
of  the  canoe,  and  a  good  test  of  whether  the  men  are  well 
together  is  afforded  by  the  noise  :  it  should  be  as  sharp 
and  well  defined  as  the  rattle  of  eight  oars  in  the  rowlocks, 


88  CANOES  AND  A  VOYAGE 

and  a  paddler  who  is  very  much  out  of  time  with  the 
rest  of  the  crew  is  greeted  with  yells  of  derision. 

The  time  is  set  by  the  two  bow  paddlers  ("  Balambi  "), 
usually  picked  men.  In  my  big  canoe  one  was  nearly 
blind  from  smallpox  ;  he  was  a  native  of  the  Sesse  Isles, 
as  are  all  the  best  canoe  men. 

The  steersman  ("  Omugoba  ")  also  is  one  of  the  best 
paddlers,  and  in  a  high  beam  wind  has  all  his  work  cut 
out  to  prevent  the  canoe  from  falling  off  her  course,  as 
I  have  often  experienced  !  For  any  slight  correction 
he  uses  a  peculiar  stroke  ;  putting  the  paddle  into  the 
v/ater  as  far  away  from  the  canoe  as  he  can  reach,  with 
powerful  jerking  movements,  all  his  body  and  arms  rigid, 
he  pulls  the  paddle  through  the  water  towards  him  with 
a  succession  of  rapid  strokes.  In  a  very  heavy  wind  and 
sea,  however,  with  a  large  canoe,  this  may  not  be  sufficient, 
and  the  steersman  then  has  to  make  a  rudder  of  his  paddle 
by  using  the  projecting  end  of  the  thwart  ("  Empumi  ") 
as  a  fulcrum,  whereby  great  leverage  can  be  obtained. 
The  bowmen  also  help  to  pull  the  canoe's  head  round 
into  the  proper  course  by  putting  the  paddle  well  away 
from  the  canoe  and  making  the  stroke  towards  the  canoe, 
on  whichever  side  it  is  necessary. 

On  March  1,  1913,  I  started  off  on  a  "joy  ride  "  to 
see  Nkosi,  the  southernmost  isle  of  all  the  Sesse  group, 
which  I  had  long  wanted  to  see.  The  party  consisted  of 
twelve  paddlers,  three  boys  and  myself,  with  food  for 
four  days  and  camp  equipment  in  one  canoe.  At  7' 30  w^e 
got  away,  on  a  glorious,  calm,  sunny  morning,  in  good 
spirits  at  the  prospect  of  a  change  after  over  a  year  spent 
in  the  same  camp  on  Bugalla.  As  we  passed  the  north- 
east cape  of  Bugalla  there  was  a  fine  Situtunga  buck  on 
the  crest  of  the  hill,  but  I  could  not  see  its  horns,  which 
the  men  said  were  of  a  good  size.  We  w^ent  southwards 
down  the  channel  between  Bugalla  and  Bunyama,  and 
it  was  so  calm  that  one  saw  well  the  lung  fish  that  came 


PITCHING    CAMP    ON    THE    ISTHiMUS    OF    KIRUGU    ISLK. 


"'^m  ■ 


THE    \Vi;>TEKN    POINT    OF    KIRUGU    ISLE   AND    THE    ISTHMUS    CONNECTING    IT 
WITH   THE   CENTRAL    RIDGE. 

To  face  p.  8 


A   VOYAGE   TO   KIllUGU  89 

up  to  the  surface  for  a  breath  of  air.  They  put  their 
mouths  right  out  of  water  for  a  second  or  two,  and  then 
turn  on  one  side  and  go  down  with  a  peculiar  roll,  nearly 
always  flourishing  one  of  the  filamentous  pectoral  fins  out 
of  the  water. 

Bunyama  sends  out  a  long  point  of  rushes  towards 
Bugalla,  so  that  the  channel  is  very  constricted,  and  the 
scenery  extremely  beautiful.  Bugalla  here  rises  steeply 
from  the  water,  the  slopes  being  forest  clad,  as  is  the  coast 
of  Bunyama.  Having  passed  this  point  we  saw  Fumvo 
in  front  of  us,  appearing  as  a  steep  grassy  hill  rising  rather 
abrupt!}''  about  350  feet,  with  forest  at  its  base.  We 
went  straight  south  between  Bubembe  and  the  prominent 
south-east  peninsula  of  Bugalla,  and  then  between  Fumve 
and  the  little  islet  of  Banda,  off  the  bay  on  its  west  coast. 
Here  the  scenery  was  lovely  ;  the  densely  forested  shore 
of  Fumve  was  reflected  in  the  blue  glassy  water  of  the 
bay,  and  Banda  was  like  an  enormous  rockery. 

At  1  p.m.  I  thought  a  halt  for  lunch  was  indicated, 
^^s^s  we  had  been  going  for  five  and  a  half  hours,  so  we  landed 
oijt'^he  south  end  of  Fumve  and  spent  about  an  hour 
there. 

We  then  made  straight  for  the  northern  end  of  Kirugu 
islet,  which  we  reached  after  another  two  hours  paddling. 
There  was  a  lovely  place  for  camping  :  a  sandy  isthmus 
well  sheltered  by  trees  under  which  the  men  could  sleep, 
and  providing  an  excellent  place  for  the  tent.  This 
narrow  neck  joined  on  to  the  main  part  of  the  island  a 
little  plateau  with  cliff -like  sides.  The  main  part  of  the 
island  is  a  long  narrow  ridge  of  grass,  falling  steeply  to 
the  water  by  cliffs  or  precipitous  slopes,  clothed  by  dense 
bushes  and  trees  wherever  they  could  cling  :  the  island 
rises  180  feet  above  the  water. 

Our  choice  of  the  sandy  isthmus  for  camping  was  much 
resented  by  some  hippos,  who  evidently  had  their  resting 
places  there,  and  grunted  and  snorted  impatiently  in  the 


90  CANOES  AND   A  VOYAGE 

water,  whither  they  had  been  forced  to  retire  on  our 
arrival.  Eggshells  of  crocodiles  were  scattered  about 
over  the  sand,  so  that  it  was  also  a  favourite  resort,  or 
at  any  rate  a  resting  place,  of  these  reptiles,  but  none 
were  seen,  which  was  fortunate,  as  a  bathe  in  the  clear 
water  was  found  most  refreshing  in  the  evening.  The 
little  sandy  neck  was  so  narrow  that  one  could  choose 
calm  or  rough  water  to  bathe  in,  according  to  the  time 
of  day.  In  the  early  morning  the  usual  northerly  land 
breeze  blew,  and  the  water  on  the  south  side  of  the  neck 
was  absolutely  calm,  to  be  ruffled  during  the  heat  of  the 
day  by  the  southerly  wind. 

Next  day  I  was  awakened  at  4  a.m.  by  the  sound  of 
waves  breaking  on  the  south  side  of  the  beach,  the  sign 
of  a  distant  storm,  which  reached  us  about  seven  :  the 
usual  burst  of  thunder  and  heavy  rain.  At  about  nine 
the  sky  began  to  clear,  and  eventually  the  day  became 
brilliant,  but  with  such  a  steady  strong  wind  that  it  was 
impossible  to  go  anywhere  in  the  canoe.  I  spent  the 
morning  taking  photographs,  and  getting  a  view  of  the 
spacious  distances  from  the  top  of  the  ridge  of  the  island. 
The  views  were  superb  ;  it  was  v/onderful  to  look  south 
and  see  nothing  but  bluest  water  with  white  capped  waves, 
and  to  think  that  there  were  ten  score  miles  of  it  between 
oneself  and  the  mainland. 

In  the  near  distance  lay  Nkosi,  the  southernmost  of 
all  the  isles  of  Sesse,  and  to  the  east  the  long  high  ridges 
of  Kuye  and  Buguye,.  with  some  smaller  isles  to  the 
immediate  west  and  north-west. 

In  the  evening  the  strength  of  the  wind  abated  a  little 
and  the  white  caps  were  no  longer  seen,  so  that  I  was  able 
to  struggle  down  the  more  sheltered  west  side  of  the 
isle  and  see  the  waves  breaking  on  the  point,  although  the 
wind  was  still  sufficiently  strong  to  make  it  very  hard 
work  for  both  paddlers  and  myself  steering.  The  sky  at 
sunset   was  full  of  wind  and  promise  of  rain  to  come, 


'N    KIKUGL'    1^LE. 


ON    KIRIGU    ISLE. 


To  face  p.  90  (first  page). 


DOWN   SOUTH   TO   NKOSI  91 

all  the  islands  to  the  north  being  seen  to  stand  out  very 
sharply  and  clearly,  and  there  being  a  thick  smoky  haze 
to  south  and  west. 

Next  day  at  sunrise  huge  masses  of  black  thunder 
cloud  were  seen  over  Bugalla,  which  evidently  was  getting 
a  heavy  storm  :  our  camp  got  a  sharp  squall  at  seven 
o'clock,  which  nearly  blew  the  tent  away  and  split  to 
ribbons  the  outer  fly. 

For  a  few  minutes  the  rain  fell  in  sheets,  but  soon  passed, 
and  by  8*30  a  breeze  cleared  it  up.  The  sun  came  out, 
and  the  day  eventually  turned  out  gloriously,  with 
sufficient  wind  and  waves  to  make  the  lake  interesting. 
We  had  a  stiff  fight  southwards  against  the  breeze,  and 
stopped  for  a  brief  rest  among  the  pretty  grottoes  on 
the  rocky  fern  clad  islet  Lukiusa,  eventually  reaching 
Nkosi  at   10- 30. 

We  first  coasted  along  the  south-east  side,  fully  exposed 
to  the  breakers  coming  up  from  the  open  lake,  so  could 
not  approach  the  shore  very  closely,  especially  as  it  was 
very  rocky,  and  no  risk  could  be  run  of  staving  in  the  canoe. 
Nkosi  is  a  little  over  a  mile  long  and  a  few  hundred  yards 
broad  ;  it  is  low,  flat  and  bush  covered,  but  the  trees  do 
not  grow  high,  presumably  owing  to  exposure  to  the 
constant  winds  from  the  lake.  We  rounded  a  tail  of  rocks 
at  the  south  end,  and  got  under  the  lea  of  the  island  into 
sheltered  water,  almost  at  once  finding  a  most  picturesque 
little  grassy  dell,  with  the  lush  green  grass  close  cropped 
as  if  by  rabbits.  This  was  the  work  of  Situtunga  antelopes, 
of  which  one  was  soon  seen  quietly  grazing.  Their  presence 
on  this  small,  very  isolated  and  exposed  island  is  of 
considerable  interest  ;  it  is  so  covered  with  thick  bush 
that  open  spaces  are  few  and  small,  and  they  can  only 
traverse  the  bush  by  definite  paths.  Since  there  can  be 
no  check  on  their  increase  save  the  amount  of  food 
available,  disease  and  the  physiological  effects  of  in- 
breeding, the  number  on  the  island  must  long  ago  have 


92  CANOES   AND   A  VOYAGE 

reached  its  maximum,  and  the  pressure  is  presumably 
relieved  by  migration  of  the  animals  from  Nkosi  by 
swimming  across  to  Buguye  a.nd  Kirugu  Islands,  and  then 
by  secondary  dispersion  to  the  large  islands  further 
north.  1 

It  is  an  interesting  problem  how  far  this  antelope  can 
swim — for  from  the  little  islet  Lukiusa,  which  could  be 
used  as  a  stepping-stone,  it  is  at  least  two  miles  to  the 
nearest  neighbour,  and  open  rough  water  has  to  be  crossed. 

Even  more  interesting  is  the  possible  presence  on  Nkosi 
of  a  species  of  Cercopithecns  monkey  ;  for  as  we  gently 
drifted  before  the  wind  uj)  the  west  side  of  the  isle  the 
voice  of  a  monkey  was  heard  among  the  trees.  I  much 
regret  that  I  did  not  see  the  animal,  for  it  is  of  course 
possible  that  the  noise  may  have  been  made  by  a  parrot, 
since  I  have  certainly  heard  one  imitate  a  monkey  on 
Kisigalla  Isle. 

The  return  journey  from  Nkosi  to  camp  was  easy,  for 
wind  and  sea  followed  and  helped  us  along,  and  I  got 
back  at  4*15  a.fter  a  most  interesting  dsby. 

Next  morning  it  was  calm  and  clouded,  and  we  broke 
camp  and  got  a^ay  at  6- 45,  having  an  uneventful  run 
as  far  as  Fumve,  taking  a  course  this  time  along  the  east 
coast,  which  is  very  picturesque. 

The  whole  side  of  the  island  forms  a  sort  of  huge 
amphitheatre  backed  by  wooded  slopes,  and  in  the  centre 
of  the  foreground  rises  extremely  steeply  from  the  water  a 
flat  topped,  grassj'^  hill,  almost  as  high  as  the  rest  of  the 
island,  about  three  hundred  feet,  making  one  think  of  a 
great  altar  in  the  centre  of  the  amphitheatre.  As  we 
passed  Fumve  a  thunderstorm  came  up  behind  us  from 
the  south-east,  and  I  had  to  alter  course,  for  it  had  been 
my  intention  to  return  along  the  east  side  of  Bubembe, 

^  Major  R.  Meiiiertzhagen,  F.Z.S.,  who  visited  Nkosi  in  one  of  the 
lake  steaiTiers  during  thf  war,  estimated  that  there  must  be  two  hvmdred 
Situtniga  on  the  island,  and  that  they  were  sulficiently  different  from  the 
Bugalla  forms  to  bo  called  a  sub-species.     (See  Chapter  VII.) 


OUTH    END   OK    NKOSE    ISLE. 
Grass  cropped  by  Situtunga. 


-CANOE   SEEN    "  BOWS   ON,"    KIRUGU    ISLE. 


To  face  p.  92, 


BACK   HOME  93 

pass  between  it  and  Bugaba,  and  then  to  the  east  of 
Bunyama.  The  rough  weather,  however,  now  made  it 
impossible  to  pass  along  the  exposed  sides  of  the  islands, 
and  we  had  to  turn  westwards  and  run  between  Bwiggi 
and  the  north  end  of  Fumve. 

As  it  was,  we  had  quite  sufficient  wind  and  waves  to 
make  steering  the  canoe  very  hard  work,  for  the  wind 
coming  from  behind  and  on  the  side  blew  the  canoe's 
head  round,  and  it  required  continual  effort  to  keep  her 
more  or  less  before  the  wind. 

However,  when  we  had  passed  through  the  narrow 
channel  between  Bunyama  and  Bugalla  we  got  into 
sheltered  water  and  were  able  to  land  on  Bunyama  for 
a  rest  and  lunch,  mid- day. 

The  storm  soon  passed,  and  the  rest  of  the  day  was 
bright  and  sunny,  and  we  eventually  got  home  again  at 
2  p.m.,  where  I  found  that  only  j'o  inch  rain  had  fallen, 
showing  that  the  storm  was  very  local. 

We  had  made  the  return  journey  in  very  good  time, 
having  travelled  about  forty  miles  between  6-45  and  2, 
with  half  an  hour's  rest. 


CHAPTER    VI 

A    TOUR    OF    INVESTIGATION    AMONG    THE 
NORTHERN    ISLANDS 

The  tour  now  to  be  described  was  made  with  Fiske  at 
the  commencement  of  1914,  its  object  being  a  comparative 
investigation  of  the  chain  of  islands  lying  parallel  to  the 
north  coast  of  the  lake,  so  far  as  could  be  done  from 
Entebbe  as  a  source  of  food  supply. 

Besides  our  two  selves  and  our  four  servants  there 
were  thirty-nine  canoe  men,  nine  fly  boys,  and  a  minor 
chief  to  act  as  headman,  with  his  attendant.  All  these, 
with  belongings,  were  stowed  away  in  two  large  canoes 
and  a  small  one  holding  five  or  six  men  only,  which  we 
subsequently  found  very  useful.  We  left  Entebbe  at 
9*15  p.m.  on  January  12th,  having  chosen  the  night  time 
because  of  the  high  wind  during  the  day,  which  would 
have  made  heavy  work  of  paddling  with  well-laden 
canoes.  It  was  a  beautifully  calm  moonlight  night,  and 
we  reached  BuLAGO  at  2-15  a.m.,  and  pitched  camp  there, 
as  it  was  to  be  our  base  for  some  days.  This  is  an 
interesting  island  of  curious  shape,  having  a  long  forest 
clad  peninsula  jutting  out  from  the  north-east  corner, 
and  a  large  bay  on  the  north  shore,  along  which  is  a  belt 
of  forest.  The  east  coast  is  almost  bare  of  trees  or  bushes, 
the  west  has  a  fringe  of  bush,  and  the  south  point  ends 
in  a  sand-spit,  much  to  the  liking  of  crocodiles.  Open 
grass  land  forms  the  centre  of  the  island,  and  rather  on 
the  western  side  two  rounded  hills  rise  a  couple  of  hundred 
feet. 

04 


BULAGO    ISLE,     NORTH    BAY   AND    FORESTED    NORTH    POINT. 
Damba  Isle  on  horizon. 


i 


THE   OPEN    GKA:,^    I  AND    INTERIOR   OF   BULAGO,    WITH    FOREST    BEll     A  i 
SHORE    OF    NORTH    BAY,    AND   ONE    OF    THE   GRASSY    HILLS. 


To  face  p.  94. 


BULAGO,    KIZIMA  95 

We  saw  a  good  deal  of  Bulago,  and  studied  it 
thoroughly,  but  found  nothing  very  characteristic  in  its 
fauna  or  flora.  A  notable  tree  was  one  called  by  the 
natives  "  Musali,"  whose  fruits  were  like  loquats  :  I 
had  seen  small  specimens  of  this  on  Bugalla,  but  here 
they  were  good-sized  trees. 

A  colony  of  the  fossorial  wasp  Bembex  was  noted  on 
crocodile  point,  where  the  sand  was  eminently  suitable 
for  their  burrows. 

We  had  decided  to  take  careful  note  of  the  butter- 
flies to  be  found  on  the  several  islands,  as  some  sort 
of  index  to  the  general  suitability  of  an  island  for 
insect  life. 

On  this  first  visit  fifty-two  species  were  noted,  and  on 
the  return  journey  in  March  twenty-two  more  were  added 
to  the  list.  It  was  on  Bulago  that  I  first  met  with  the 
Acraeine  species  Planema  aganice  and  PI.  alcinoe,  neither 
of  which  occurred  on  Bugalla  or  Damba,  though  Damba's 
immediate  neighbour  Kome  was  subsequently  found  to 
have  these  interesting  butterflies. 

On  January  14th  we  visited  the  islet  of  Kizima.  This 
is  only  about  300  yards  in  diameter,  and  rises  out  of  the 
water  as  a  rocky,  flat  topped,  grass  clad  eminence,  with 
shrubs  and  small  trees  along  the  steep  coast  line,  and  one 
little  bay  with  sandy  beach  on  the  west.  A  tangle  of 
"  Oluzibaziba  "  bushes  sheltered  a  hippo  ;  a  large  and  a 
small  crocodile  and  two  large  monitor  lizards  {Varanus, 
called  "  Enswa-swa  "  by  the  natives)  were  seen  ;  the 
basking  places  of  the  latter  on  the  rocks  were  very 
numerous. 

Among  the  branches  of  a  bush  I  found  a  small  elapine 
snake,  light  grey  with  dark  brown  blotches,  which  had 
very  obviously  dined  both  wisely  and  well  !  Rodents, 
about  the  size  of  a  water  vole,  were  abundant  on  this 
isle  ;  their  runs  were  very  noticeable,  and  also  the  debris 
of  grass  stems  left  where  they  had  been  feeding.     Kizima 


96  A  TOUR  AMONG  THE   ISLANDS 

was  therefore  alluded  to  as  a  "  rat  island  " ;  several  others 
will  be  described  later. 

The  little  hill  of  Kizima  seems  to  act  as  a  chimney 
directing  a  continual  current  of  air  upwards,  for  whenever 
it  v.'as  visited  there  were  always  numbers  of  kites  soaring 
round  and  round  in  narrow  circles  just  over  the  island. 
Around  it  are  fragments  of  rocks  that  have  broken  away 
and  now  form  resting  places  for  many  cormorants  and 
darters  ;  snow-white  egrets  with  black  bills  and  legs, 
Egyptian  geese,  and  a  giant  heron  were  also  there,  with 
a  sacred  ibis,  not  to  be  seen  on  every  island. 

Flycatchers  were  seen,  and  swallows  were  fairly  plentiful. 

Butterflies  were  few  (see  p.  125)  :  Glossina  was  repre- 
sented by  an  average  catch  per  fly  boy  of  29  per  hour 
(both  sexes).  No  termite  hills  were  seen  ;  indeed,  ter- 
mites seemed  altogether  absent. 

The  Island  of  Tavu  was  first  visited  on  January 
13th.  It  is  about  a  mile  in  greatest  diameter,  being 
low  and  flat  and  covered  thickly  with  vegetation. 
The  northern  two-thirds  are  marshy,  and  only  ambatch 
grows  there,  with  a  dense  fringe  of  rushes  ;  the  southern 
end  is  very  sandy  and  covered  with  cane,  "  E'tungulu," 
and  bushes,  with  rushes  growing  in  the  shallow  water. 
On  the  west  coast  is  a  large  raised  beach  of  sand,  which 
was  found  to  provide  admirable  breeding  places  for 
Glossina.  The  rest  of  the  island  has  forest  growth,  and 
was  at  one  time  cultivated.  Tavu  proved  to  be  a  favourite 
haunt  of  crocodiles,  of  which  nine  were  seen  ;  some  on 
a  rock  on  the  east  coast,  others  in  the  shallow  water  off 
the  sandy  south  point,  on  which  they  lay  their  eggs. 
No  "  Enswa-swa "  were  seen,  and  subsequent  visits 
always  showed  them  to  be  scarce. 

Of  snakes,  the  beautiful  horned  puff  adder  (Bitis 
nasicornis)  was  seen,  and  a  large  black  elapine  was  rather 
common. 

Birds   abounded  ;     giant   herons,   and   herons   of  other 


TAVU— RESUVU  97 

species,  glossy  ibis,  the  open-billed  stork,  egrets  and  a 
stone  curlew  were  seen,  while  cormorants  and  darters 
were  numerous  in  the  ambatch  trees,  on  which  they  nest. 

In  the  thick  jungle,  where  we  very  easily  lost  our  sense 
of  direction,  the  abundance  of  insect  life  was  shown  by 
bee-eaters,  flycatchers,  coucals  and  other  insectivorous 
birds. 

Butterflies  were  numerous  (see  table,  p.  125),  and  forest 
species  such  as  Planema  macarista,  two  species  of  Charaxes, 
and  a  large  Euralia  were  noted.  Three  species  of  Tabanidae 
were  noted  on  the  shore,  possibly  the  low  lying  and  marshy 
ground  is  suitable  for  the  larvae  ;  a  common  Tabanus 
{T.  variatus),  a  Haematopota  and  Chrysops  brucei  were 
the  species  seen,  the  latter  quite  plentiful,  and  one  was 
seen  in  the  grip  of  a  predaceous  Asilid  fly.  Termites 
abounded,  and  the  Dorylus  ant  was  seen,  while  Culicine 
mosquitoes  bit  unpleasantly  in  the  jungle. 

Large  Achatina  snails  were  plentiful. 

Olossina  was  very  abundant,  the  island  furnishing 
ideal  conditions  of  food,  shelter  and  breeding  grounds. 
The  average  catch  per  boy  hour  was  39' 2. 

On  January  17th  I  visited  the  sand  bank  south  of 
Tavu,  named  Resuvu.  Its  north  half  is  submerged  at 
all  times,  and  there  is  a  dense  growth  of  ambatch  on 
which  cormorants  and  darters  nest.  The  south  half,  at 
this  time,  was  above  water,  and  measured  about  50  by 
20  yards,  but  is  probably  almost  entirely  submerged  when 
the  lake  level  is  high.  Notwithstanding,  I  found  larvae 
of  a  very  common  Noctuid  moth  ;  in  the  sand  a  small 
black  ant  was  found,  and  I  saw  a  nest  of  the  Belonogaster 
wasp,  which  feeds  its  larvae  on  caterpillars. 

On  January  24:th  we  moved  camp  to  Nsadzi  Island, 
pausing  on  the  way  to  examine  Kimmi,  which  we  found 
extremely  interesting,  since,  though  quite  small  and  flat, 
it  contains  portions  of  almost  every  kind  of  condition  met 
with  on  the  lake  shore.     We  landed  first  on  the  south- 

8 


98  A    TOUR  AMONG  THE  ISLANDS 

west  side,  whose  eastern  tip  is  formed  of  sand  left  by  the 
receding  lake  at  the  foot  of  a  low  cliff  in  which  are  caves, 
full  of  bats.  Further  westwards  the  shore  is  low,  of  flat 
rocks,  with  many  holes  kept  full  of  water  by  waves  ;  at 
a  higher  level  is  a  sand  beach  now  grown  over  by  cane 
and  bushes,  and  used  as  a  nesting  ground  by  crocodiles. 
The  north-west  shore  is  flat  and  marshj^  with  a  thick 
fringe  of  rushes  and  bushes  of  "  E'tungulu  "  and  ambatch  ; 
the  north-east  part  of  the  island  is  forested,  but  near  the 
water  is  a  large  patch  of  open  grass  land,  with  very  sandy 
soil,  in  which  "  Enswa-swa  "  burrow  and  lay  their  eggs. 
The  south-east  shore  is  marshy,  with  lush  grass  much 
frequented  by  hippos  ;  this  type  of  shore  was  dubbed 
*'  Hippo  Grazing  Ground." 

The  vegetation  of  Kimmi  seemed  to  me  much  more 
varied  than  on  Tavu,  which  is  about  the  same  size.  A 
Chrysophyllum  tree  (Sapotaceae),  knoAvn  to  the  Basesse  as 
"  Omugalati,"  which  was  not  seen  on  either  Bulago  or 
Tavu,  an  anonaceous  shrub  scarce  on  the  other  two  isles 
but  abundant  here,  and  a  shrub  with  clusters  of  fragrant 
white  flowers,  which  I  had  not  seen  before,  were  noted. 
Butterflies  were  fairly  abundant,  a  forest  Papilio,  with 
several  forest  Planema,  were  noted  ;  the  numbers  counted 
will  be  found  in  the  table  (p.  125). 

The  most  striking  feature  of  Kimmi  was  the  vorac'ty 
of  Glossina,  which  came  off  in  a  swarm  to  the  canoe  before 
we  had  touched  land,  and  bit  ferociously.  It  was  found 
that  more  than  half  the  number  caught  were  females, 
which  is  quite  exceptional  ;  the  significance  of  this  has 
been  discussed  in  the  chapter  on  Glossina.  We  comforted 
ourselves  with  the  recollection  that  former  experiments 
had  never  shown  the  flies  from  Kimmi  to  be  infective, 
and  put  up  with  the  inconvenience  as  best  we  could. 
The  average  catch  per  boy-hour  for  this  island  reached 
the  high  figure  of   60*  9  :    on   one   day  alone  it  was  81  ! 

The  hunger  of  the  fly  tallied  with  the  fact  that  we  found 


f 


a    ^ 


NGAMBA  99 

no  crocodiles  or  **  Enswa-swa,"  the  favourite  source  of 
food  ;  although  hippos  are  fond  of  the  island  I  do  not 
consider  them  of  much  importance  as  food  for  the  fly, 
which  has  therefore  to  depend  for  food,  on  Kimmi,  mainly 
on  birds  which  frequent  the  shore. 

On  January  30th  we  visited  Ngamba,  which  lies  between 
Kome  and  Nsadzi,  This  island,  like  Tavu,  is  covered 
with  forest  growth,  but  is  more  rocky  and  rises  higher  ; 
it  is  roughly  square,  and  of  about  the  same  size  as  Kimmi. 
The  forest  everywhere  comes  close  to  the  water's  edge 
save  on  the  east  side,  where  part  of  the  shore  is  marshy, 
and  at  the  rocky  north-east  point.  The  shore,  on  the 
whole,  is  either  rocky  or  pebbly,  and  only  at  the  north- 
west corner  is  there  a  raised  beach  of  sand.  Along  the 
south  coast  the  rock  is  grey,  but  at  the  north-east 
point  is  of  the  more  common  spongy  red  brown 
formation. 

As  usual  we  first  circumnavigated  the  isle,  and  counted 
six  crocodiles  and  three  "  Enswa-swa  ;  "  two  others  were 
also  seen,  and  bushes  of  "  Oluzibaziba  "  bore  evidence 
that  Situtunga  antelope  had  been  browsing  on  them  : 
probably  these  had  swum  across  from  Kome,  where  they 
live,  for  none  were  seen  on  Ngamba.  The  forest  trees  were 
noted  to  be  varied  ;  one  very  fine  fig  tree  with  huge 
leaves,  also  occurring  on  Kimmi,  was  conspicuous  here  : 
the  natives  called  it  "  Omululu."  Another  noticeable  tree 
had  sprays  of  greenish  flowers  like  those  of  Portuguese 
laurel  :  the  natives  called  it  "  Omuziru  "  ;  and  another, 
with  large  white  flowers,  was  called  "  Omukoba." 

Here  and  there  were  beds  of  a  magnificent  herb  which 
I  took  to  be  at  least  allied  to  Salvia,  with  spikes  of  large 
blue  flowers,  growing  up  to  a  height  of  four  or  five  feet. 
This  was  subsequently  often  found  growing  in  pebbly 
places  near  the  water,  and  was  quite  a  feature  of  some 
islands.  Of  birds,  a  sacred  ibis  and  giant  heron  were 
noted,  but  no  other  notes  were  made.     There  were  some 


/ 


100  A  TOUR  AMONG  THE   ISLANDS 

features  of  interest  in  the  insect  fauna  :  a  D.  chrysippus 
was  seen  crossing  the  channel  betAveen  Ngamba  andNsadzi, 
and  nests  of  the  interesting  ant  (Ecophylla  smaragdina, 
and  the  fierce  'little  black  ant  called  by  the  natives 
"  Obusaji-saji,"  were  found  on  leaves  of  trees  ;  they  are 
not  by  any  means  universally  distributed  among  the 
islands. 

The  tubular  cases  of  larvae  of  some  species  of  Psychid 
moth  were  seen  on  the  tree  trunks  in  great  numbers,  and 
afforded  the  first  example  of  the  fact  that  a  small  circum- 
scribed area  may  support  only  a  few  species,  but  that  some 
of  these  may  flourish  much  more  abundantly  than  in  larger 
areas  where  they  are  exposed  to  greater  competition. 
During  the  course  of  this  tour  many  other  examples  were 
noted,  and  will  be  mentioned  as  instances  of  "  insularity  " 
in  the  fauna  or  flora. 

Glossina  was  scarce  on  Ngamba,  the  average  catch  being 
9"  9  per  boy-hour.  We  remained  at  Nsadzi  camp  until 
February  5th,  but  spent  only  a  little  time  over  the  island 
itself,  since  it  was  too  big  to  be  thoroughly  investigated 
on  a  short  visit.  It  is  about  three  miles  long,  but  very 
narrow  :  four-fifths  consist  of  a  steep  grassy  ridge  almost 
bare  of  trees  but  with  innumerable  termite  hills,  closer 
together  than  I  ever  saw  anywhere  else.  At  the  centre 
of  the  south  side  of  the  island  cliffs  descend  steeply  to  a 
sandy  bay,  with  a  strip  of  forest  at  the  foot  of  the  cliffs. 
There  is  another  patch  of  forest  on  the  north  side,  but 
elsewhere  the  shore  has  only  a  very  narrow  fringe  of  bush. 
The  eastern  fifth  of  the  island  is  low  and  flat,  and  sharply 
marked  off  by  the  escarpment  of  the  end  of  the  main 
ridge  ;  it  is  covered  with  forest,  full  of  birds.  On  Nsadzi 
we  found  most  interesting  evidence  of  insularity.  The 
grass  on  the  uplands  had  been  burnt  off  by  Fiske  on  a 
previous  visit  some  weeks  before,  and  the  new  green  blades 
were  growing  up  among  the  burnt  black  stems  of  the 
tussocks.     Over  an  area  of  a  great  many  square  yards 


^H 

■           4 

M                                              1 

r| 

^1 

1                                       9 

NSADZI  TO   KOME  101 

every  blade  had  been  eaten  by  caterpillars  of  a  Noctuid 
moth,^  whose  green  and  black  colours  harmonized  abso- 
lutely with  those  of  the  grass.  These  caterpillars  were 
hurrying  about  in  all  directions  looking  for  more  food, 
and  numbers  of  a  brown  "  Ichneumon  "  were  seen 
depositing  eggs  in  them.  While  piercing  the  larva  with 
its  ovipositor  the  ichneumon  grasped  it  firmly  in  its 
mandibles,  a  habit  which  is  shared  by  the  stinging  fossors, 
who  have  adopted  a  somewhat  more  advanced  kind  of 
parasitism. 

On  Nsadzi  were  found,  firstly  by  Fiske,  the  footprints 
of  a  large  Situtunga  buck  ;  the  importance  of  this  has 
been  alluded  to  in  the  chapter  on  Glossina. 

We  moved  from  Nsadzi  on  February  5th  to  a  new 
base  on  the  east  end  of  Kome,  whence  we  intended  to 
examine  the  small  islands  of  that  neighbourhood. 

It  was  a  most  lovely  voyage  on  a  calm  and  clear  day, 
with  much  cloud  of  varied  type  and  deep  purple  shadows. 
We  left  Nsadzi  at  7  a.m.,  and  travelled  past  the  tips  of 
the  several  peninsulae  jutting  out  from  the  north  shore  of 
Kome,  and  then  down  the  beautiful  channel  between 
Damba  and  Kome,  where  blue,  pink  and  white  water 
lilies  were  in  full  flower.  A  small  cloud  funnel  was  seen, 
giving  warning  of  a  short  storm  which  came  from 
the  east  at  about  4  p.m.,  and  burst  on  us  while  we  were 
on  Sanga  Islet,  but  only  lasted  for  half  an  hour.  I  was 
much  interested  in  this,  because  while  I  had  been  encamped 
on  Damba  in  1911,  only  a  few  miles  from  Sanga,  which 
could  be  plainly  seen  (see  map),  I  had  never  had  an 
afternoon  storm  there,  but  had  noticed  that  the  end  of 
Kome  often  caught  rain  which  missed  my  camp. 

Sanga  Islet  was  examined  this  day,  and  was  found  to 
be  amazingly  interesting.  It  only  measures  about  100 
by  60  yards,  is  very  rocky  and  well  covered  with  forest, 
and  shows  abundant  evidence  of  insularity. 

*  Laphygma  frtigiperda  (Xenobianae). 


102  A  TOUR  AMONG  THE  ISLANDS 

The  shore  is  composed  of  broken  rocks,  and  the  forest 
comes  to  the  water,  but  there  is  very  little  undergrowth 
of  bushes,  so  that  we  were  able  to  walk  about  freely. 

Glossina  was  absent  :  the  other  arthropod  life  was  of 
great  interest.  The  first  thing  noticed  was  the  abundance 
of  very  large,  long-legged  black  and  yellow  spiders 
(Nephila),  which  spin  webs  several  feet  in  diameter. 
These  great  webs  formed  sheets,  often  in  planes  one  behind 
another  when  the  branches  offered  suitable  support, 
so  closely  placed  that  the  spiders  on  the  central  sheets 
could  hardly  get  any  insects  on  their  webs,  and  looked 
starved.  Sanga,  therefore,  was  known  as  a  "  spider 
island,"  and  others  will  be  described  later.  The  next 
feature  noted  was  the  unusual  abundance  of  predaceous 
Mantidae,  and  this  was  associated  with  absence  of  insecti- 
vorous birds  ;  a  very  interesting  example  of  the  "  balance 
of  nature." 

At  the  time  of  this  visit,  and  we  remained  on  the  island 
several  hours  searching  it  thoroughly,  I  neither  saw  nor 
heard  a  single  flycatcher,  bee-eater,  coucal,  or  any  of 
the  common  small  warblers  ;  parrots  and  weavers  were 
the  only  birds  noted  in  the  forest.  At  a  second  visit, 
however,  one  "  Kunguvu  "  flycatcher  was  noted,  and  the 
call  of  a  common  cuckoo  was  heard.  Perhaps  correlated 
with  this  absence  of  insectivorous  birds  was  the  fact, 
which  Fiske  and  I  noted  independently,  that  the  butter- 
flies, especially  the  mimetic  Euralia  and  Aterica  galene 
which  I  have  always  found  very  difficult  to  catch  on  account 
of  their  shyness,  were  here  much  less  shy  and  easier  to 
catch.  Fiske  thought  that  it  was  on  account  of  the 
multitude  of  spiders'  webs,  which  had  resulted  in  the 
butterflies  flying  more  slowly  and  cautiously  to  avoid 
them  ;  but  I  noticed  that  when  on  the  ground  the  mimics 
were  more  easily  approached  than  is  usually  the  case. 

The  numbers  of  butterflies  found  on  Sanga  are  given  in 
the  table  (p.  125) ;  the  most  noteworthy  feature  was  unusual 


SANGA— KISIGALLA  103 

abundance  of  the  large  Hesperid  Rhopalocampta  chalybe, 
whose  peacock  green  and  blue  wings  flashed  in  the  sun  as 
these  beautiful  butterflies  darted  about  in  the  sunlight 
in  typical  "  skipper  "  fashion.  Acraeines  were  represented 
by  two  species  among  the  tree  tops  out  of  reach,  and  one 
specimen  of  A.  egina  ;  Amauris  niavius  was  the  only 
Danaine  seen  ;  of  Nymphalines,  Euralia  dubia,  E. 
dinarcha,  and  a  forest  Charaxes  were  noted  ;  while  the 
large  and  beautiful  iridescent  Salmnis,  its  pale  green 
wings  suffused  with  a  pink  mother  of  pearl  lustre,  was 
very  plentiful.  Lastly,  the  caterpillars  of  an  aposematic 
moth,  Aletis  erici  (see  description,  p.  214),  were  very 
abundant  on  Sanga,  which  interested  me  more  than  any 
other  island,  because  it  was  the  first  visited  of  those  on 
which  the  great  spiders  were  so  abundant,  and  showed 
so  many  other  examples  of  insularity. 

On  February  11th  we  visited  the  little  isle  Kisigalla, 
lying  close  to  Sanga,  and,  like  it,  rocky  and  covered 
with  trees,  but  with  one  piece  of  sandy  shore.  It  is 
about  fifty  yards  in  diameter,  and,  though  so  close 
to  Sanga,  differs  from  it  in  many  respects.  It  was 
characterized  by  almost  entire  absence  of  the  Nephila 
spiders  so  abundant  on  Sanga  ;  by  abundance  of  a  large 
black  Scoliid,  of  cocoons  of  the  gregarious  caterpillars  of 
Lasiocampid  and  Eupterotid  moths,  and  also  of  a  very 
large  fawn  coloured  slug. 

Birds  were  not  so  scarce  as  on  the  spider-haunted 
Sanga  ;  the  "  Kunguvu  "  flycatcher,  sunbirds,  weavers, 
pigeons,  and  the  beautiful  blue  and  crimson  plaintain- 
eater  were  all  noted. 

Butterflies  were  quite  plentiful,  the  most  interesting 
being  the  large  mimetic  Lycaenid  Mimacraea  poultoni, 
and  the  Nymphaline  mimics  Psevdacraea  eurytus  forms 
hobleyi  and  tirik^nsis.  A  very  fine  Satyrine  that  was  new 
to  me  escaped  capture.  Glossina  was  scarce,  the  catch 
per  boy-hour  reaching  only  the  average  of  2-3. 


104  A  TOUR  AMONG  THE   ISLANDS 

The  islet  Lula,  close  to  Kisigalla,  was  visited  on  the  same 
day,  and  was  found  to  differ  considerably  from  its  neigh- 
bour. It  consists  of  a  small  rocky  ridge  covered  by  bushes 
and  not  by  large  trees,  and  is  much  frequented  by  crocodiles, 
whose  basking  places  are  numerous.  Of  birds,  a  black 
and  white  flycatcher,  not  met  with  on  any  other  of  the 
five  islets  off  the  east  end  of  Kome,  was  noted  to  be 
relatively  plentiful.  Neither  the  spiders  of  Sanga  nor 
the  slugs  of  Kisigalla  were  found  on  Lula.  Butterflies  were 
interesting  (see  p.  125)  ;  Acraeines  were  more  numerous 
than  any  other  group,  forming  seven-fifteenths  of  the  total 
number  of  species  found;  A.  pentapolis  was  noteworthy, 
as  it  is  not  found  on  every  isle.  The  Nymphalines  were 
rather  surprising  :  a  huge  Euralia,  looking  very  out  of 
place  among  bushes  on  a  tiny  islet,  Pseudacraea  eurytus 
form  obscura,  Ps.  lucretia  and  Salamis  made  up  the  total. 
The  only  Lycaenid  found  was  a  brown,  black  spotted 
Pentila,  whose  Acraeine  appearance  fitted  in  well  with  the 
prevailing  group  of  the  island. 

Colonies  of  Eupterotid  larvae  were  seen  on  Lula  as  on 
Kisigalla. 

The  average  catch  of  Glossina  was  9*  1  per  boy  per  hour. 

On  February  6th  we  worked  Dwanga  Mkuru,  the 
largest  of  three  closely  associated  islands  lying  off  the 
eastern  point  of  Kome.  This  is  about  three  miles  long, 
and  very  narrow  ;  generally  speaking,  its  features  are 
of  the  type  associated  with  a  clear,  rocky  shore. 

The  centre  is  a  grass  topped  ridge  sloping  steeply  on 
the  east  down  to  the  rocky  or  pebbly  shore,  where  at  one 
point  a  dyke  of  red,  spongy  volcanic  rock,  stuffed  with 
fragments  of  grey  rock  as  a  pudding  is  stuffed  with  plums, 
runs  out  across  the  pebbly  beach.  On  the  west  side  is  a 
bold  cliff,  at  the  sheltered  foot  of  which  is  a  strip  of  thick 
fertile  forest,  with  some  huge  "  Omuvule  "  (African  teak) 
trees,  and  an  overgrown  banana  plantation.  All  along 
the  shore  on  the  east  are  thick  beds  of  fern  and  Salvia, 


DWANGA   MKURU   AND  MTO  105 

backed  by  thin  and  poor  looking  forest  trees,  swept  by 
the  prevailing  south-east  winds.  Many  of  them  were 
covered  with  spiders'  webs,  for  this  island  is  markedly  a 
"  spider  island  "  ;  as  on  Sanga,  this  is  correlated  with 
great  scarcity  of  insectivorous  birds  and  abundance  of 
Mantidae. 

Butterflies  were  extremely  abundant :  the  beautiful 
green,  pinkly  iridescent  Salamis  was  more  numerous 
than  at  any  other  locality  visited,  four  might  be 
seen  at  once.  Of  Acraeines,  Planema  poggei  was  of 
interest,  and  other  Nymphalines  besides  Salamis  were 
Euralia  duhia  and  Pseudacraea  hicretia,  which  latter 
Fiske,  until  it  had  been  caught,  thought  must  be  a 
Neptis  from  its  flight.  I  had  often  noticed  that  its 
flight  was  much  more  like  that  of  a  Neptis  than  the 
Danaine  (Amauris),  which  it  somewhat  resembles  in 
pattern. 

Glossina  was  completely  absent  from  Dwanga  Mkuru. 

DwANGA  Mto,  lying  alongside  the  last  named,  was 
visited  on  February  9th.  It  is  more  or  less  covered  by 
jungle,  but  there  are  some  open  patches,  and  it  does  not 
rise  so  high  as  its  larger  neighbour.  The  shores  are  mostly 
of  pebble  or  rock,  with  much  fern  and  Salvia,  and  the 
usual  common  bushes. 

A  species  of  bush  was  seen  by  the  water  which  had  not 
been  met  with  before  ;  it  had  very  large  heart  shaped 
leaves  and  spikes  of  inconspicuous  flowers  :  the  natives 
called  it  "  Omukwakula."  Other  features  of  the  flora 
were  a  single  specimen  of  the  large  "  Ekibo  "  palm  and  a 
small  patch  of  elephant  grass  ("  Ekisagazi  "),  which  is 
very  unusual  on  the  small  islands. 

Birds  were  not  so  noticeably  scarce  as  on  Dwanga 
Mkuru,  for  sunbirds  and  bulbuls  were  plentiful  and  the 
"  Kunguvu  "  flycatcher  was  there. 

Being  markedly  a  "  spider  island,"  Dwanga  Mto  had 
abundant  Mantidae;  the  large  grasshopper  called  "E'jansi" 


106  A  TOUR  AMONG  THE   ISLANDS 

by  the  natives  was  much  more  plentiful  than  on  other 
islands  hitherto  visited. 

Regarding  butterflies,  the  most  noteworthy  feature  was 
the  abundance  of  the  large  Hesperid  Rhopalocampta 
forestall,  hitherto  not  encountered  on  the  small  islands  ; 
its  near  ally,  the  beautiful  Rh.  chalybe  of  Sanga  Isle,  was 
not  seen  here.  The  single  Papilionine  (see  table,  p.  125) 
was  P.  leonidas,  whose  Danaine  model  Meliyida  petiverana 
was  also  seen.  Acraeines  were  so  extraordinarily  scarce 
that  I  only  caught  one  specimen,  and  only  one  other 
species  was  seen.  Nymphalines  included  Salamis,  which 
was  very  abundant,  Pseudacraea  eurytus  forms  hobleyi 
and  terra,  Ps.  lucretia,  Euralia  dubia,  two  Charaxes, 
a  Neptis,  and  H.  misippus  and  C.  cardui,  neither  of  which 
occurred  on  other  islets  of  this  group. 

A  curious  Lycaenid  was  found  here,  a  large  grey  species 
with  angulated  wings. ^  A  feature  of  the  island  fauna  was 
the  number  of  long  narrow  cases  of  the  larvae  of  a  Psychid 
moth,  attached  to  tree  trunks. 

Glossina  was  almost  absent ;  the  nine  fly  boys  could  only 
catch  four  males  and  a  female. 

The  third  island  of  this  group,  Dwasendwe,  was 
visited  on  February  10th. 

It  is  covered  everywhere  with  forest  or  overgrown 
plantations  ;  almost  everywhere  the  shores  are  rocky  ;  on 
the  north-east  there  is  a  dense  bank  of  ferns.  The  main 
insular  feature  of  Dwasendwe  was  the  great  abundance 
of  the  Aletis  larva  first  met  with  on  Sanga  ;  these  had 
defoliated  the  food  plants  over  a  large  area. 

Of  butterflies,  Acraeines  were  again  very  scarce,  one 
Planema  and  one  small  Acraea  only  were  seen  ;  of  Hes- 
peridae  the  large  Gamia  bucholzi,  with  mottled  underside, 
was  noted  :  a  Lycaenid  was  found  which  was  never  met 
with  on  any  other  island,  and  was  apparently  associated 
with  the  ''  Omukwakula"  bushes  on  whose  flowers  it  seemed 

^  Aslauga  purpurascens,  Lipteninae. 


■'>.vi:/i*i/;!>^ifcii^^ 


MAUNGWE  107 

to  be  ovipositing.  Although  this  bush  was  abundant  on 
the  neighbouring  island,  Dwanga  Mto,  this  Lycaenid  had 
not  been  seen  there.i  It  is  a  large  white  species 
with  fine  hair-like  wavy  lines  on  the  under  surface.  On 
this  island  was  found  in  a  spider's  web  a  second  specimen 
of  the  West  African  Lycaenid,  first  caught  on  Dwanga 
Mto.  Dwasendwe  was  markedly  a  "  sj^ider  island  "  ;  and 
Glossina  was  absent. 

On  February  13th  we  moved  camp  to  Kerenge  Isle, 
one  of  a  group  lying  further  eastwards.  Fiske  and  I 
started  at  6-30  with  four  paddlers  in  the  small  canoe,  as 
we  intended  to  visit  sundry  islets  en  route,  leaving  the  big 
canoes  with  kit  and  men  to  find  their  more  laborious  way 
in  their  own  time. 

At  daybreak  there  were  very  threatening  clouds,  with 
thunder  to  the  south-east,  and  it  seemed  as  if  we  must 
get  caught  by  a  storm.  The  canoe  men  paddled  furiously 
to  get  to  our  first  islet,  and  the  small  canoe  seemed  to 
leap  out  of  the  water  at  every  stroke,  so  that  the  un- 
fortunate Fiske  in  the  bows  got  very  splashed,  as  there 
was  som^e  swell  from  the  distant  storm.  After  one  and  a 
half  hours'  paddling  for  the  distance  of  six  miles,  we  safely 
arrived  at  Maungwe,  a  rock  spit  only  about  80  by  30 
yards  in  size,  thickly  covered  with  ferns,  herbs,  low  bushes 
and  Ipomaea  creepers  with  a  few  fig  trees,  on  a  fork  of 
one  of  which  was  an  enormous  nest,  possibly  of  a  heron 
or  a  bird  of  prey.  A  very  common  weed,  with 
dull  mauve  flowers  (Erlangea  tomentosa,  called  by  the 
natives  "  Obutwatwa  "),  grew  very  tall  and  in  dense 
masses  which  sheltered  a  small  bird  with  the  habits  of  a 
flycatcher,  brown,  with  white  throat  and  belly  and  brown 
chest,  which  was  subsequently  found  on  minute  islets 
only,  nearly  always  in  masses  of  the  "  Obutwatwa." 
It  had  a  very  sweet  voice,  and  its  song  resembled  part  of 
a  nightingale's  repertoire,   so  I  dubbed  it  for  reference 

^  Spalgis  pilos. 


108  A  TOUR  AMONG  THE   ISLANDS 

sake  "  Nightingale  flycatcher."  Swallows  and  weavers 
feeding  on  the  "  Sami  "  gnats  were  also  plentiful,  and 
small  lizards  were  seen. 

No  Lepidoptera  were  notedj  although  a  Belonogaster 
wasp  was  seen,  which  is  known  to  feed  its  grubs  on  cater- 
pillars. Two  species  of  carpenter  bees  which  bore  into 
wood,  and  small  ants,  were  seen,  but  there  were  no  Glossina 
on  Maungwe. 

By  the  time  we  had  finished  with  this  little  island 
all  threatenings  of  storm  had  passed  off,  and  we  went 
on  happily  to  Enkusa  Islet,  merely  a  reef  of  red  spongy 
rock  for  the  most  part  broken  into  pebbles,  with  a 
dense  growth  of  ambatch  bushes  at  one  end,  inhabited 
by  weaver  birds.  There  was  a  great  growth  of  a  large 
yellow  vetch,  1  which  seems  to  prefer  pebble  beaches  in 
the  vicinity  of  water.  One  small  and  feeble  Lycaenid 
lived  on  this  islet,  keeping  close  to  the  ground. 

From  Enkusa  we  went  to  Zmo,  going  round  Isentwa 
and  through  a  break  in  a  reef  which  almost  joins  the  two, 
into  a  very  secluded  bay  dubbed  by  Fiske  "the  Pirates' 
Haven."  Here  we  lunched,  and  afterwards  went  up  on  to 
the  central  grassy  hill  to  get  a  broad  idea  of  this  island 
and  its  neighbours. 

The  general  appearance  of  this  group  was  not  at  first 
sight  inviting,  after  the  beautiful,  forested  and  friendly 
islands  of  the  Kome  group.  They  have  grassy  hills,  but 
much  less  true  forest  growth  :  the  pyramidal  grass  clad 
peak  of  Kiuwa  was  very  striking,  apparently  rising  straight 
out  of  the  water,  treeless,  as  high  as  the  highest  point  of 
any  island  of  the  neighbourhood. 

We  did  no  work  on  Ziro  this  day,  but  visited  it  subse- 
quently. The  only  notable  feature  about  its  coast  is  a 
rocky  headland  at  the  south-east  point,  with  caves  of 
weird  fashioning  quite  suited  for  pirates'  lairs  ! 

I  noted  that  the  flora  of  the  isle  in  some  respects  rather 

^  Crotalaria  striata. 


ZIRO— SPIDERS'    WEBS  109 

differed  from  that  of  the  group  we  had  just  examined, 
for  several  flowers  were  seen  that  had  not  been  previously 
noted  but  which  had  been  noted  at  Jinja,  on  the  main- 
land, in  1910.  Two  instances  of  butterflies  similarly 
occurred  ;  and  these  facts  suggested  that  these  isles  had 
not  been  connected  with  the  former  group,  but  only  with 
that  part  of  the  coast  immediately  to  the  north  of  them, 
the  others  perhaps  having  derived  their  inhabitants  from 
the  mainland  more  to  the  west.     (See  map.) 

As  regards  birds,  several  giant  herons,  a  dappled  grey 
heron  which  I  had  not  seen  before,  and  open-billed  storks 
in  great  numbers  were  seen. 

Flycatchers  were  seen  and  heard  in  fair  number ; 
Enswa-swa  lizards  seemed  fairly  numerous,  for  nine  were 
noted. 

Ziro  is  markedly  a  "  spider  island,"  but  Mantidae  were 
not  noticeably  abundant.  Of  butterflies,  Acraeines  were 
very  abundant ;  A.  encedon  in  several  forms  was  note- 
worthy, A  Lycaenid^  was  taken  which  I  found  at  Jinja 
in  1910,  but  had  riot  been  met  with  on  any  of  the 
islands  :  this  is  notable  after  what  has  been  said  about 
the  flora. 

Glossina  was  far  from  abundant,  the  average  being 
6-8  per  boy-hour. 

We  remained  in  our  camp  on  Kerenge  from  February 
13th-20th,  using  it  as  a  base  from  which  to  visit  neigh- 
bouring isles.  There  was  nothing  very  characteristic 
about  it ;  it  is  flat  and  has  a  good  deal  of  open  grass  land, 
and  there  are  remains  of  former  banana  plantations,  now 
full  of  the  great  spiders'  webs  to  a  disgusting  degree  : 
to  get  one's  face  and  hat,  or  bare  arms,  covered  with  the 
sticky  clinging  web  was  extremely  unpleasant.  So  strong 
is  the  silk  that  a  sunbird  was  seen  in  a  web,  having  become 
so  entangled  that  it  could  not  free  itself  ;  we  managed  to 
reach  up  to  it  with  a  long  stick  and  set  it  free.  The  webs 
*  Lachnoenema  bibulus. 


110  A  TOUR  AMONG  THE   ISLANDS 

were  so  close  that  the  spiders  on  those  between  others 
were  quite  starved  and  their  bodies  very  shrunken. 

Mantidae  were  not  noticeably  conspicuous  ;  the  large 
"  Amajansi  "  grasshoppers  were,  and  the  beautiful  king- 
fishers which  feed  on  them  were  also  abundant.  Acraeine 
butterflies  were  not  so  abundant  as  on  Ziro,  indeed  here 
they  were  almost  absent  ;  Lycaenidae  were  relatively  so 
abundant  as  to  be  the  main  feature  of  the  butterfly  fauna. 
Of  Hesperidae  the  large  Gamia  bucholzi  was  noted,  and 
Fiske  found  a  shady  bank  where  large  numbers  of  a 
Hesperid  new  to  me  were  to  be  seen  ;  ^  it  seemed  to  be 
associated  with  a  plant,  probably  of  the  Arum  family, 
which  carpeted  the  ground  here.  Glossina  only  averaged 
62  per  boy-hour. 

We  visited  Lukalu  Isle  on  February  16th,  and  found  it 
very  interesting.  About  half  a  mile  long,  but  narrower, 
its  greater  part  is  a  grassy  plateau  rising  slightly  in  the 
centre,  with  large  beds  of  bracken  on  the  slopes  ;  at  the 
east  end  are  some  high  rocks  with  caves,  and  here  are  a 
few  big  trees.  One  of  these  was  like  the  common  tree  ^ 
called  "  Ekirikiti  "  by  the  Baganda,  but  the  spiky  flowers 
instead  of  being  scarlet  were  of  a  rosy  pink  tint  which  I 
had  not  seen  before. 

From  the  eastern  end  of  the  isle  stretches  along  the 
south  shore  a  narrow  strip  of  dense  bush  ;  the  north  shore, 
however,  is  very  different,  there  being  a  belt  of  thick  cane 
growing  on  sand,  on  which  were  marks  showing  that 
crocodiles  had  lain  there,  and  hippos  had  made  tunnels 
through  the  cane  thicket. 

Five  Enswa-swa  were  seen.  The  only  birds  that  attracted 
attention  were  a  coucal  and  a  grey  plaintain  eater  ;  the 
"  Kunguvu  *'  flycatcher  was  not  seen.  No  Nephila  spiders 
were  seen ;  of  butterflies  Lycaenidae  predominated ; 
Lachnocnema  bihulus  was  caught ;  Acraea  encedon  was 
in  great  variety ;  the  only  Nymphaline  seen  was  Precis 

^  Andronymua  lemider.  -  Erythrina  tomentosa. 


LUKALU— ISENTWA  111 

clelia.  Glossina  averaged  10- 6  per  boy-hour.  There  is  a 
small  accessory  islet  to  the  east  of  Lukalu,  separated 
from  the  main  isle  by  about  50  yards  of  water  ;  it  measures 
about  100  by  50  yards,  and  is  composed  of  red  rock  broken 
up  into  pebbles  on  its  surface.  There  was  a  variety 
of  flowering  plants  and  low  bushes  at  one  end,  and 
many  ambatch  trees,  among  which  a  species  of  moor- 
hen was  noted.  Weaver  birds,  sunbirds  and  wagtails 
were  plentiful. 

The  only  butterflies  noted  on  this  accessory  islet  were 
the  Lycaenid  T.  telicanus,  which  was  evidently  much 
attacked  by  wagtails,  for  a  large  proportion  had  a 
A -shaped  piece  taken  symmetrically  out  of  the  two  hind 
wings. 

On  February  16th  we  visited  Isentwa  Isle,  which  is 
roughly  triangular,  having  sides  about  three  hundred 
yards  long. 

It  is  composed  almost  entirely  of  grass  land,  with  a 
narrow  fringe  of  bush  or  cane  at  those  parts  of  the  coast 
where  the  rock  is  not  too  steep.  Enswa-swa  were  noted 
abundantly,  but  no  crocodiles  were  seen  ;  indeed,  as  a 
whole  the  islands  of  this  group  had  very  few  crocodiles. 

Big  spiders  were  absent  from  Isentwa,  and  also  Glossina  ; 
butterflies  were  very  few,  the  feature  being  abundance 
of  the  woolly-legged  Lycaenid  Lachriocnema  bibulus,  of 
which  at  least  half  a  dozen  individuals  arose  together 
from  one  plant  as  I  passed.  The  only  Nymphaline  seen 
was  Precis  archesia. 

KiuwA  Island  was  visited  on  February  19th,  and  proved 
to  be  remarkably  interesting  from  the  point  of  view  of 
the  bionomics  of  Glossina,  which  was  found  to  the  extent 
of  18-2  per  boy-hour,  and  yet  we  could  not  make  out  where 
were  the  pupae  which  kept  the  numbers  at  this  level. 

Search  as  we  would,  no  more  than  an  average  of  3*  3 
pupae  could  be  found  per  boy-hour,  in  spite  of  rewards 
offered. 


112  A  TOUR  AMONG  THE   ISLANDS 

As  has  been  said,  the  island  consists  mainly  of  a  steeply 
rising  grass-clad  conical  hill,  a  little  over  a  mile  long  and 
half  as  broad  ;  its  north-east  end  slopes  less  steeply, 
and  here  is  evidence  of  former  banana  cultivation,  the 
shambas  now  overgrown  with  bush  and  creepers  ;  some 
of  the  rose  flowered  "  Ekirikiti "  trees  first  noted  on 
Lukalu  were  seen.  There  were  also  thick  bushes  of  the 
usual  kinds,  and  beds  of  the  Salvia-\ike  plant.  Along  the 
south-east  shore  are  bold  cliffs,  at  the  foot  of  which  are 
two  little  bays  with  beaches  of  pebble  ;  the  south-west 
shore  is  formed  of  unbroken  rocky  strata  rising  steeply 
from  deep  water  ;  the  west  shore  slopes  less  steeply  and 
is  fringed  by  bushes,  so  that,  on  the  whole,  the  island 
seems  unfavourable  for  Glossina,  which  yet  was  numerous. 
Three  crocodiles  and  one  Enswa-swa  were  seen,  but  no 
traces  of  hippo.  Fruit  eating  bats  were  abundant,  and 
small  rodents  were  very  numerous  in  the  tussocky  grass, 
so  that  Kiuwa  was  called  a  "  rat  island." 

In  the  old  banana  plantations  sunbirds  and  weavers 
were  very  plentiful  ;  flycatchers  were  scarce,  and  none 
of  the  black  and  white  species  were  seen.  A  thrush  was 
heard  singing,  which,  though  plentiful  at  Entebbe  on  the 
mainland,  I  had  never  heard  before  on  an  island. 

Only  one  single  specimen  of  Nephila  spider  was 
seen ;  no  termite  hills  were  seen  anywhere  on  the 
island.  1 

The  butterflies  of  Kiuwa  were  rather  interesting  (see 
table,  p.  125) ;  three  species  of  small  brown  Acraea  were  ex- 
tremely abundant,  but  encedon  was  not  seen.  Nymphalines 
were  very  scarce  ;  a  Pierine  scarcely  ever  met  with  on  the 
islands  was  quite  abundant  on  the  beaches  on  the  south- 
east shore ;  two  Lycaenids  not  common  everywhere 
were  noted  as  abundant ;  Hesperidae  were  very  scarce  in 
individuals,  and  only  four  species  were  seen. 

On  February  20th  we  moved  camp  from  Kerenge  to  the 

^  Cp.  Kizima,  also  a  "  rat  island," 


ZIGUNGA— WEMA  118 

south  side  of  Wema  Isle,  visiting  Kibibi  ew  route,  and  also 
the  Islet  of  Zigukga. 

This  consists  of  two  small  islets  joined  by  an  isthmus, 
so  that  the  south-west  coast  forms  a  bay  :  it  is  composed 
of  red  rock,  covered  with  grass  and  rising  steeply  ;  there 
are  a  few  fig  trees. 

A  feature  of  the  island  was  a  plant  with  thick,  sword 
shaped  leaves,  from  which  the  natives  obtain  fibre.  One 
crocodile  and  two  Enswa-swa  were  seen. 

Swallows,  weavers  and  sunbirds  were  quite  common, 
and  it  was  interesting  to  find  again  the  "  Nightingale 
flycatcher "  frequenting  thick  clumps  of  the  plant 
Erlangea  ("  Obutwatwa  ")  as  it  did  on  Maungwe  Isle. 
No  Nephila  were  found,  nor  were  Glossina  seen  ;  a  single 
Acraea  and  a  long-tailed  Lycaenid,  abundant  on  Kiuwa, 
were  the  only  butterflies  noted. 

After  visiting  Zigunga  we  went  on  to  Wema,  a  large 
island  on  whose  south  shore  our  new  camp  was  pitched, 
and  used  it  as  a  base  until  March  2nd.  It  was  much 
too  big  to  be  thoroughly  examined  in  the  time  at  our 
disposal,  so  we  confined  ourselves  to  the  south  shore. 

The  views  of  Wema  itself  obtained  from  the  summit  of 
the  hill  behind  the  camp  were  quite  the  most  beautiful 
of  any  I  have  seen  on  an  island. 

There  are  four  hills  on  the  island,  of  which  the  one  above 
alluded  to,  at  the  south-west  corner,  is  grassy  and  flat 
topped  ;  another,  at  the  north-west  corner,  is  flat,  with  a 
patch  of  forest  running  nearly  to  the  top  ;  on  the  con- 
necting ridge  between  these  two  is  more  forest,  which 
also  runs  up  the  third  hill,  the  central  one  of  the  isle, 
grass  clad  on  top.  The  fourth  hill  at  the  north-east 
corner  has  a  grassy  base  and  a  cap  of  forest  on  top.  The 
south-east  coast  of  the  island  has  a  fine  fly  beach  with 
forest  at  the  back,  and  the  eastern  point  shows  a  red  cliS 
visible  from  the  camp.  From  the  top  of  the  hill  behind 
the  camp  a  lovely  panoramic  view  was  seen  on  the  first 

9 


114  A  TOUR  AMONG  THE   ISLANDS 

evening  ;  looking  eastwards  across  Yempata  and  Bus'ri 
one  saw  distant  Buvuma,  lying  in  the  mouth  of  the  gulf 
which  gradually  narrows  down  to  the  origin  of  the  Nile  at 
Jinja  (see  map)  ;  to  the  west,  Damba  lay  long  and  low  on 
the  horizon,  flooded  with  golden  light  from  a  lovely  sunset. 

The  part  of  Wema  that  was  investigated  proved  most 
interesting  ;  Glossina  was  extremely  abundant,  averaging 
55  per  boy-hour,  and  at  one  spot  the  catch  averaged  101"  5 
per  boy-hour  ;  one  boy  caught  78  in  half  an  hour  ! 

Monkeys  were  seen  for  the  first  time  since  we  left  Kome, 
and  I  was  struck  by  the  abundance  of  a  black  and  white 
crow  which  flew  about  in  flocks  like  rooks.  Wema  proved 
to  be  very  markedly  a  "spider  island,"  and  as  regards 
butterflies  it  was  richer  than  any  of  the  other  islands 
investigated ;  I  think  that  it  has  probably  as  many 
species  as  the  much  larger  Damba  or  Bugalla,  and 
several  Nymphalines  were  seen  there  which  had  not 
been  met  with  on  the  larger  isles. 

Of  Papilioninae,  P.  dardanus  and  P.  ugandae,  with  several 
other  forest  species,  were  noted  ;  also,  P.  leoyiidas  and 
P.  policenes  were  very  common.  Of  Pierinae,  several 
species  of  Terias  and  one  Teracola  were  noted.  The 
following  species  of  Nymphalines  were  especially  noted  : 
Pseudacraea  boisduvalli,  lucretia,  and  eurytus  forms  hobleyi 
and  tirikensis,  six  species  of  Neptis,  together  with  Nepti- 
dopsis,  nine  of  Charaxes  ;  Salamis  was  fairly  abundant, 
while  no  Euralia  was  seen.  Danaines  were  poorly  repre- 
sented by  a  few  D.  chrysippus,  Amauris  echeria,  A.  niavius 
and  yl,  psyttalea.  Only  a  few  specimens  of  each  were  seen. 
Acraeines  were  surprisingly  scarce  ;  very  few  individuals, 
belonging  to  nine  species,  were  found  ;  noteworthy  were 
Planema  alcinoe,  macarisfa  and  poggei.  The  Hesperidae 
included  the  peacock  blue  Rhopalocampta  chalybe ; 
among  the  Lycaenidae  was  an  extremely  beautiful  large 
blue  species,  with  long  tails  of  snowy  white  hue  {Zeltus 
antif annus). 


MARIDA— WAVUZIWA  115 

Perhaps  the  most  interesting  butterfly  of  the  islands 
was  a  Libythea  caught  by  Fiske  ;  no  species  of  this  family 
had  been  met  with  previously  on  any  isle.  A  total  of 
124  species  was  found  on  this  brief  visit  to  Wema,  and 
probably  half  as  many  again  would  be  added  by  further 
investigation  (see  p.  125). 

On  February  21st  we  visited  two  of  the  small  islets 
Ijang  east  of  Wema,  going  first  to  Marida,  which  consists 
of  two  flat,  grassy  portions  connected  by  an  isthmus 
along  which  is  a  pebbly  beach.  There  is  no  forest  growth, 
but  low  bushes  and  fig  trees  form  a  fringe  along  parts  of 
the  shore.  A  coniferous  tree,  Podocarpus,  called  by  the 
Basesse  "  OmusSnene,"  was  here  noted  for  the  first  time. 
A  crocodile  was  seen,  and  a  nest  of  eggs  found,  and  two 
Enswa-swa  were  found  on  the  island. 

The  only  point  noticed  about  bird  life  was  that  bee- 
eaters  were  there  in  some  number,  and  they  do  not  frequent 
every  island  ;  sunbirds  also  were  quite  common  on  the 
isthmus,  and  the  "  Kunguvu  "  flycatcher  was  seen. 

Marida  is  very  decidedly  a  "  spider  island  "  ;  Glossina 
was  represented  by  an  average  catch  of  4*6  per.  boy-hour. 
Of  butterflies,  it  was  remarkable  that  no  Acraeines  were 
seen,  and  while  individuals  of  other  species  were  scarce, 
a  fair  number  of  species  was  seen  (see  p.  125). 

The  feature  of  Marida  was  the  abundance  of  a  slug, 
broadly  resembling  the  English  L.  agrestis,  but  with  a 
little  fleshy  spike  on  the  end  of  the  body  reminding  one 
of  the  caudal  horn  of  a  Sphingid  larva  ;  this  species  had 
not  been  met  with  before. 

From  Marida  we  went  on  to  Wavuziwa,  a  rocky  islet 
with  very  little  shade  except  from  fig  trees  ;  ferns  were 
abundant.  One  crocodile  and  one  Enswa-swa  were  seen  ; 
of  birds,  weavers  and  sunbirds  were  plentiful,  also  the 
"  Nightingale  flycatcher,"  and  one  coucal  was  seen. 

Glossina  was  very  scarce,  for  all  the  fly  boys  together 
in  an  hour  only  caught  seven  ;     Nephila  was  not  seen  at 


116  A  TOUR  AMONG  THE   ISLANDS 

all ;  of  butterflies,  Acraea  zetes,  of  rather  Eastern  type, 
was  notable,  and  no  Nymphalines  were  seen.  Insular 
features  of  Wavuziwa  were  two  ;  a  Lymantrid  caterpillar 
new  to  me  ^  was  found  in  abundance  feeding  on  the 
"  Anyamberege  "  plant,  on  which  plant  I  had  never 
previously  found  any  caterpillar,  and  fluffy  white  masses 
of  some  species  of  Coccidae,  which  thickly  infested  bushes 
and  undergrowth. 

On  February  26th,  Sege  was  visited  ;  a  not  very 
interesting  island  of  the  same  size  as  the  last  named, 
rocky,  covered  with  grass  and  without  any  beach.  Rather 
conspicuous  on  this  islet  was  the  fibrous  leaved  plant 
found  previously  on  Zigunga,  and  an  aloe  whose  spikes 
of  scarlet  blooms  arose  from  rosettes  of  fleshy,  thorny 
edged  leaves. 

Two  Enswa-swa  were  found  on  the  island  ;  one,  the 
biggest  I  ever  saw,  was  much  less  timorous  than  usual, 
and  did  not  retreat  into  the  water  until  I  approached 
within  a  few  yards  of  it,  after  which  it  remained  close  at 
hand  with  its  head  above  water. 

Of  bird  life  the  only  notable  feature  was  the  "  Nightingale 
flycatcher  "  ;  Nephila  was  absent,  Glossina  very  scarce,  for 
the  nine  boys  in  an  hour  only  caught  twenty-seven,  all 
males  ;  of  butterflies,  ten  species  were  noted. 

Wait  WE  was  visited  on  the  26th  ;  it  has  a  central 
grass  hill  rising  above  the  level  of  any  of  the  neighbours, 
and  sloping  precipitously  to  the  water  on  the  west  side. 
It  is  partly  clothed  with  bracken,  and  the  shores  every- 
where are  steep  and  rocky  ;  there  is  a  fair  variety  of 
trees  and,  in  contrast  with  Sege,  abundance  of  ferns. 
Waitwe,  like  Kiuwa,  is  pre-eminently  a  "  rat  island,"  the 
tussocky  grass  being  penetrated  in  all  directions  by  their 
runs.  Perhaps  on  account  of  this  a  small  python  was 
found  on  the  island,  in  a  cave. 

Three  Enswa-swa  were  seen  ;  of  birds,  the  "  Kunguvu  " 

1  Eucoma  otricosta. 


YEMPATA  lir 

flycatcher  was  present,  and  the  familiar  notes  of  a  common 
bulbul  made  one  realize  that  it  had  not  been  found  on 
every  island,  Nephila  was  absent ;  ten  species  of  butter- 
flies were  noted ;  Olossina  very  scarce,  for  the  nine  boys 
only  caught  six  in  half  an  hour. 

On  February  24th  we  visited  Yempata  Isle,  going  first 
to  a  minute  accessory  islet  lying  off  its  southern  end. 
This  was  noteworthy  by  the  scarcity  of  the  "  Oluzibaziba  " 
bush  ;  there  were  some  fig  trees  and,  on  the  eastern  side, 
"  Ekinsambwe "  bushes.  No  ferns  were  noted,  but 
Ipomaea  was  abundant,  and  the  whole  centre  of  the  islet 
was  covered  with  masses  of  a  thick  leaved  aromatic, 
labiate  herb  with  spikes  of  purple  flowers,  and  the  mauve 
flowered  "  Obutwatwa  "  {Erlangea  tomentosa),  in  which, 
as  on  other  small  islets,  the  sweet  song  of  the 
"  Nightingale  flycatcher  "  was  heard. 

Birds  abounded  on  this  islet  ;  on  the  rocks  surrounding 
it  were  cormorants,  gulls,  egrets  and  giant  heron  ;  moor- 
hens were  among  the  bushes  on  the  eastern  shore,  and 
many  swallows  and  weaver  birds  were  noted.  Nephila 
and  Glossina  were  absent ;  the  only  butterfly  was  a 
Lycaenid  ;    bees  were  seen  on  the  flowers. 

The  main  island  of  Yempata  is  rather  flat,  but  there  is  a 
small  amount  of  open  grass  land  rising  slightly  at  about 
the  centre  ;  the  rest  is  well  covered  with  forest  or  the 
overgrown  remains  of  former  plantations. 

For  at  least  half  the  length  of  the  western  shore  there  is 
a  pebbly  beach,  backed  by  dense  thickets  of  elephant 
grass  ("  Ekisagazi  "),  an  unusual  feature  on  any  but  the 
largest  islands.  The  remainder  of  the  west  coast  has  a 
dense  wall  of  bushes  ;  along  the  north  coast  there  are 
rushes  and  papyrus,  and  on  the  east  side  papyrus,  ambatch, 
and  other  bushes  right  up  to  the  water's  edge,  forming 
excellent  shelter  for  the  Siibutunga  antelope  which  the 
natives  assert  lives  on  the  island.  Along  the  southern 
shore  is  pebbly  beach. 


118  A  TOUR  AMONG   THE   ISLANDS 

The  old  banana  plantations  bore  evidence  that  monkeys 
live  on  YemjData,  but  thej^  were  -not  seen.  Hippos,  of 
course,  visited  Yempata,  for  old  plantations  are  favourite 
resorts  of  theirs  ;  only  one  crocodile  and  one  Enswa-swa 
were  seen.  Nothing  is  recorded  in  my  journal  about  the 
birds  of  Yempata.  Butterflies  were  numerous,  but  nothing 
of  particular  interest  was  seen,  and  in  one  visit  to  an  island 
of  this  size  no  estimate  could  be  made  of  their  numbers. 
Nephila  spiders  were  not  seen  ;  Glossina  was  extremely 
abundant  and  as  hungry  as  on  Kimmi,  and,  as  at  Kimmi, 
came  off  to  the  canoe  before  we  reached  the  shore.  The 
average  for  the  island  was  67-6  per  boy-hour  ;  but  for 
the  western  beach  only  the  figure  was  79-5  ! 

On  February  28th  I  visited  Sindieo  alone  ;  an  island 
about  the  size  of  Bulago,  with  a  low  grassy  hill  at  the 
north  end  and  a  rather  flat  southern  point,  the  shores 
all  round  having  a  belt  of  very  thick  forest  coming  down 
like  a  wall  almost  to  the  edge  of  the  water.  In  front  of 
the  forest  are  thickets  of  cane,  e'tungulu  and  papyrus, 
in  places  so  dense  that  landing  was  impossible,  and  we 
had  to  go  round  to  the  eastern  side  of  the  south  point ; 
here  w^e  found  a  hippo  pathway  up  which  we  crept 
ashore  and  found  ourselves  in  a  large  open  sandy  space, 
in  which  were  numerous  burrows  of  Enswa-swa,  presumably 
nesting  places,  as  on  Kimmi. 

Sindiro  proved  to  be  very  decidedly  a  "  spider  island," 
and  Glossina  was  represented  by  an  average  of  9-2  per  boy- 
hour,  in  both  of  which  respects  this  island  shows  interest- 
ing di£Eerences  from  its  neighbour  Yempata.  Cicadas 
singing  on  the  trees  seemed  to  be  more  numerous  than 
had  been  noted  on  other  islands  ;  of  butterflies,  the 
Hesperidae  seemed  especially  numerous  in  proportion  to 
the  rest. 

On  March  2nd  we  moved  camp,  since  food  supplies  were 
running  low  and  Wema  was  too  far  from  Entebbe  for 
conveniently    replenishing.     So,    to    my    regret,    we    left 


"-^-■^''■" 


KIBIBI  119 

beautiful  Wema  and  returned  to  the  former  camp  on 
Kerenge,  visiting  Kibibi  en  route. 

This  island,  about  a  mile  square,  was  too  big  to  be 
thoroughly  examined  in  the  time  at  our  disposal  ;  it  has 
a  sugar-loaf,  grassy  hill  rising  to  the  usual  height,  and  a 
good  deal  of  park  land  with  trees  scattered  singly  or  in 
clumps  ;  on  the  north  point  is  some  really  beautiful  old 
forest,  which  is  bordered  at  the  water's  edge  by  the  tallest 
thicket  of  Salvia  that  had  been  seen  on  the  islands. 
Crocodiles  and  Enswa-swa  were  both  scarce  on  Kibibi. 
Song  thrushes  were  heard  singing  sweetly  in  some  number, 
and  the  fine  blue  and  red  plaintain-eater  ("  Fulungu  ") 
was  noted  ;  this  is  usually  not  found  on  the  smaller 
islands,  though  one  was  seen  on  Kiuwa. 

Only  a  single  Nephila  spider  was  seen.  It  was  not 
possible  to  estimate  the  butterflies,  but  it  was  interesting 
to  find  a  species  of  Byhlia^  which  had  not  been  seen  on 
any  other  island,  though  it  was  found  abundantly  at 
Jinja  on  the  mainland  in  1910. 

On  March  3rd,  Kiuwa  was  again  visited,  and  again 
worked  very  thoroughly  without  success  in  finding 
breeding  grounds  for  the  Glossina.  I  found  three  pupae, 
which  were  more  than  any  one  else  found. 

On  this  visit  was  noted  another  butterfly  which  had  not 
been  seen  since  1910  at  Jinja,  a  very  beautiful  milky 
blue  Lycaenid  which  was  quite  abundant. ^  Next  day, 
owing  to  supplies  having  run  very  low,  we  returned 
westwards  to  a  camp  on  the  north  shore  of  the  large, 
flat,  forested  island  of  Damba.  The  camp  was  pitched  in 
one  of  the  few  open  spaces,  and  was  memorable  for  the 
myriads  of  mosquitoes. 

En  route  we  examined  the  Isle  of  Dyavodemu,  lying 
in  a  bay  near  the  mainland,  and  I  visited  it  again  on  the 
6th.  It  is  flat  and  without  forest ;  at  one  time  it  had  been 
much  cultivated,  but  the  shambas  were  quite  overgrown. 

^  See  p.   109.  -  Castalius  isis. 


120  A  TOUR  AMONG  THE   ISLANDS 

The  shores  generally  are  bordered  by  a  thin  growth  of 
bushes  ;  on  the  south  side  is  a  pretty  bay  backed  by  a 
small  cliff,  at  the  foot  of  which  bushes  have  apparently 
been  used  as  a  nesting  place  by  egrets  for  many  years. 
Birds  were  few  on  Dyavodemu  ;  no  flycatchers,  bee-eaters 
or  coucals  were  found,  and  especially  noteworthy  was  the 
complete  absence  of  weavers,  which  had  been  found  on 
almost  all  islands  examined  hitherto. 

Abundant  on  this  island  was  a  lizard  which  had  not 
been  seen  in  such  number  before  :  a  short-legged,  grey 
species,  longitudinally  striped,  with  a  bluish  tint  at  the 
base  of  the  tail. 

Dyavodemu  was  emphatically  a  "  spider  island,"  not 
only  the  large  Nephila  being  abundant,  but  also  a  smaller, 
reddish,  thorny  backed  species  with  shorter  legs  being 
much  more  abundant  than  on  other  islands  where  it  had 
been  seen.  Olossina  was  represented  by  an  average  of 
101  per  boy-hour. 

Butterflies  were  interesting  (see  p.  125).  Papilio  demo- 
docus  was  seen  ;  Pierines  were  much  more  abundant  in 
individuals  than  on  other  isles.  Catopsilia  and  a  Beleyiois 
were  plentiful,  and  the  latter  could  be  seen  in  numbers 
crossing  over  from  the  mainland.  Only  two  Nymphalines 
were  found.  Precis  clelia  and  archesia  ;  Acraeines  were 
abundant  in  species  as  well  as  individuals  ;  the  most 
conspicuous,  and  so  unusually  plentiful  as  to  be  a  feature 
of  the  fauna,  was  the  rosy  pink  A.  natalica  pseudegina  ; 
A.  zetes  was  scarce,  egina  was  not  seen,  encedon  was  in 
some  variety.  Of  Danaines,  only  D.  chrysippus  was  met 
with  ;  Lycaenids  and  Hesperids  were  few,  both  in  species 
and  individuals.  Other  insular  features  were  the  great 
numbers  of  Asilid  flies,  and  of  two  species  of  beetles 
(Cassididae).  It  is  possible  that  abundance  of  the 
predaceous  flies,  in  the  presence  of  multitudes  of  spiders, 
corresponded  with  abundance  of  Mantidae  on  other 
spider  islands,  for  Mantidae  were  not  found  to  be 
numerous  on  Dyavodemu. 


MTIOMU   ISLET  121 

The  beetles  were  on  the  Ipoinaea  creeper,  much  of  which 
was  stripped  of  leaves  by  the  activities  of  them  and  their 
larvae.  One  was  brown  in  colour  with  rough  surface  ;  ^ 
the  other  smooth  light  brown,  with  very  variable  and 
irregular  black  spots. ■^ 

On  March  5th  Fiske  went  to  Entebbe  on  business,  and 
planned  to  meet  me  with  supplies  at  the  old  camp  on 
Bulago  on  the  7th. 

I  went  to  visit  the  small  islets  lying  off  the  coast  of 
Damba,  close  to  the  camp.  The  first,  Mtiomu,  of  spongy 
brown  rock,  measures  about  100  by  20  yards,  and  has  a 
fine  sand  spit  at  the  southern  end  ;  in  the  water  at  the 
north  end  is  a  great  grove  of  ambatch,  which  sheltered 
abundant  cormorants  and  weavers.  For  such  a  small 
island  the  vegetation  was  extraordinarily  varied  ;  except 
for  "  Oluzibaziba  "  all  the  familiar  bushes  and  flowering 
plants  of  the  lake  shore  were  represented,  so  that  several 
species  of  butterflies  might  have  been  expected  ;  but 
only  T.  telicanus,  the  cosmopolitan  Lycaenid,  was  found. 
Sunbirds  and  wagtails  were  seen,  and  particularly  interest- 
ing was  the  presence  of  the  *'  Nightingale  flycatcher."  A 
small  brown  lizard  was  very  abundant.  Nephila  spiders 
were  absent,  also  Olossina. 

Of  Hymenoptera,  several  species  of  bees  and  Scoliidae  were 
seen,  and  also  the  black  and  yellow  Sceliphron  spirifex. 

The  insular  feature  of  Mtiomu  Islet  was  the  great 
abundance  of  two  large,  conspicuous,  aposematic  beetles  ; 
one  a  black  and  canary  yellow  species  of  Cetoniidae,^ 
evil  smelling,  and  freely  exposed  on  the  flowers,  the  other 
a  Longicorn,*  black  with  transverse  red  bands,  which 
fed  on  the  green  bark  of  sundry  shrubs. 

Both  of  these  are  common  insects,  but  were  never 
found  elsewhere  in  such  numbers. 

The  adjoining  Islet  Tokwi  is  much  smaller,  consisting 

^  Anpidomorpha  near  moufletti.       ^  Aspidomorpha  near  signatipcnnis 
'  Pachnoda  sinuata.  *  Ceroplesis  signata  {Lamiidae). 


122  A   TOUR  AMONG   THE   ISLANDS 

merely  of  a  few  rocks  and  sand,  with  scanty  vegetation. 
Except  for  one  Enswa-swa  and  weaver  birds  and  the 
"  Nightingale  flycatcher,"  there  was  little  to  note  about 
the  fauna. 

The  tiny  islet  named  Kawaga  was  visited  next ;  merely 
a  flat  topped  rock  about  ten  yards  in  diameter,  rising 
sheer  out  of  the  water  and  about  three  feet  above  it. 
All  round  the  edge  grows  the  "  Omuvuvumye  "  shrub, 
but  nothing  else  save  grass.  Even  this  tiny  islet  had 
its  entomological  feature  ;  for,  feeding  on  the  leaves  of 
the  only  kind  of  bush  were  great  numbers  of  black  larvae 
of  a  small  Chrysomehd  ^  beetle,  brown  and  black.  More 
interesting  still  was  their  complete  absence  from  a  pre- 
cisely similar  but  slightly  smaller  rock  about  twenty 
yards  away,  and  from  a  third  a  little  further  away  still. 
I  visited  Mtiomu  again,  but  could  not  find  any  of  these 
beetles  or  their  larvae  on  the  "  Omuvuvumye  "  shrub  there. 

On  March  6th  I  visited  Masovwi,  a  diminutive  neighbour 
of  Dyavodemu,  which,  measuring  about  200  by  50  yards 
and  lying  very  low,  is  formed  of  grey  rock  and  has  a  good 
deal  of  sand  on  it.  The  southern  shore  is  marshy,  and 
fringed  for  half  its  length  with  a  dense  thicket  of  ambatch, 
the  other  half  is  open,  with  lush  grass  and  flowers  like  a 
small  sunflower.  The  centre  of  the  island  is  piled  with  sand, 
on  which  grow  thick  bushes  of  "  Ekinsambwe,"  and  in 
which  a  batch  of  crocodile's  eggs  were  found,  the  crocodile 
also  being  seen.  On  the  whole,  the  vegetation  was  not 
varied,  and  there  was  no  "  Oluzibaziba." 

Birds  were  represented  by  a  heron,  many  cormorants, 
and  moorhens,  with  weavers,  sunbirds  and,  since  the  islet 
was  very  small,  the  "  Nightingale  flycatcher."  Nephilu  was 
absent,  and  Olossina,  rather  to  my  surprise,  was  caught  at 
the  rate  of  2*1  per  boy-hour.  Pupae  were  found,  so  that 
Masovwi  is  the  smallest  isle  on  which  Glossina  is  known  to 
breed. 

^  Mesoplatys  ochroptcra. 


MOVING   CAMP   IN   A   STORM  123 

On  March  7th  I  moved  camp  to  Bulago  ;  the  dawn 
was  very  stormy  looking  and  there  were  spots  of  rain 
until  9  a.m.  It  then  seemed  as  if  danger  of  a  storm  was 
over,  and  I  set  off  in  the  small  canoe,  heavily  laden  and 
low  in  the  water,  but  hardly  had  we  got  well  away  from 
Damba  when  we  were  caught  in  a  formal  thunderstorm, 
coming,  fortunately,  more  or  less  from  astern.  The  small 
canoe  plunged  heavily  and  took  a  good  deal  of  water  over 
the  bows,  and  it  was  necessary  to  shift  some  of  the  load 
further  aft,  rather  a  difficult  procedure,  as  the  canoe  was 
full  and  far  from  steady.  However,  after  this  she 
rode  better,  and  we  proceeded  on  our  way  to  Bulago, 
getting,  of  course,  thoroughly  soaked  with  the  heavy 
rain. 

In  the  evening  there  was  great  dissatisfaction  among 
the  men  on  account  of  the  small  amount  of  food  available, 
each  man's  portion  being  only  about  half  a  dozen  bananas. 
While  ruefully  trjdng  to  make  two  and  two  into  five, 
to  my  great  relief  I  saw  Fiske's  canoe  in  the  distance 
returning  from  Entebbe,  and  aU  was  well,  for  he  brought 
abundant  supplies  and  a  huge  mail. 

March  8th  and  9th  were  occupied  with  work  on  Bulago, 
on  March  10th  we  went  to  Tavu,  and  on  the  1 1th  to  Kizima, 
where  I  heard  the  "  Nightingale  flycatcher,"  not  previously 
noted  there. 

The  12th- 15th  were  spent  on  Bulago,  and  on  the  16th 
we  moved  to  our  former  camp  on  Nsadzi,  visiting  Kimmi 
en  route  and  working  there  again  on  the  17th.  Ngamba 
was  re-visited  on  the  18th,  and  Nsadzi  itself  was  worked 
on  the  19th. 

The  results  of  these  second  visits  to  the  above  islands 
were  most  interesting,  as  the  numbers  of  Glossiria  were 
found  to  have  greatly  increased. 

On  March  21st  I  visited  Rumfua  Island,  which  lies 
off  the  south  coast  of  Kome.  A  rocky,  bush  covered 
isle,  about  half  a  mile  long,  but  very  narrow,  the  shore 


124  A  TOUR  AMONG  THE   ISLANDS 

formed  of  boulders,  except  for  a  shingle  beach  at  the 
northern  end. 

In  the  preliminary  circumnavigation  five  Enswa-swa  were 
seen,  but  no  crocodiles.  Rumfua  is  decidedly  a  "  spider 
island,"  and  the  masses  of  their  webs  among  the  dense 
bush  prevented  one  from  walking  over  it.  A  great  many 
hippo  lairs  were  seen,  so  that  the  island  seems  to  be  a 
favourite  sleeping  place  for  them.  Birds  were  scarce  ; 
there  were  no  weavers  or  sunbirds,  and  only  one  "  Kung- 
uvu  "  flycatcher  was  seen.  A  large  flock  of  egrets  was 
noted  on  the  shore.  Egg  capsules  of  Maniidae  were 
particularly  noticeable,  though  the  insects  themselves 
were  not  abundant  at  the  time. 

The  only  butterflies  noted  were  three  Lycaenids  and  a 
Nymphaline,  viz.  the  common  T.  telicanus  and  an  equally 
common  Lycaenesthes,  and  the  rare  Aphnaeus  orcas  ;  the 
solitary  Nymphaline  was  a  fine  Euralia. 

On  March  22nd,  with  Fiske's  departure,  our  joint  tour 
came  to  an  end.  Apart  from  the  results  obtained  bearing 
on  the  bionomics  of  Glossina,  many  extremely  interesting 
facts  had  been  noted  regarding  the  predominance  on 
certain  islands  of  one  or  another  type  of  insect  ;  and  it 
was  very  interesting  to  see  how,  when  the  great  spiders 
abounded,  insectivorous  birds  were  absent  and  the  "  balance 
of  nature  "  was  maintained  by  an  abundance  of  Mantidae 
or  Asilidae  keeping  down  insects  which  might  otherwise 
have  been  devoured  by  birds. 


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CHAPTER  VII 

MAMMALS 

The  Hippopotamus. 

An  animal  of  such  large  size  as  the  hippo,  called  by  the 
Baganda  "  Envubu,"  must  naturally  come  before  one's 
notice  from  time  to  time,  but  one  really  did  not  see  much 
of  him.  My  first  acquaintance  with  him  dates  from 
Jinja  in  1910,  where  a  number  could  be  seen  in  a  large 
pool  about  a  couple  of  miles  down  the  river  below  the 
falls.  The  steep  banks  leading  down  to  the  river  were 
scored  by  the  constant  passage  of  these  heavy  animals 
over  the  same  track,  until  lanes  had  been  worn  in  the  soft 
soil  several  feet  deep,  of  the  width  of  the  hippo's  body, 
bearing  an  absurd  resemblance  to  miniature  Devonshire 
lanes. 

The  bush  on  the  banks  was  so  thick  that  one  could  only 
get  down  to  the  water  by  using  a  hippo  track,  and  wondered 
when  so  doing  what  a  hippo  would  do  if,  when  ascending, 
we  happened  to  meet.  For  he  certainly  could  not  have 
turned.  When  on  the  islands  one  sometimes  found  the 
tunnels  made  through  dense  growth  of  reeds  quite  useful 
for  getting  about,  though  it  was  very  fatiguing  to  walk 
half  doubled  up,  and  the  soft  mud  was  often  unpleasantly 
odoriferous. 

During  the  day  time  the  hippo  spends  his  time  resting 
in  shallow  water,  or  else  sleeps  in  his  favourite  quarters, 
for  he  seems  to  be  very  much  attached  to  particular 
places,   and  one  would  usually  find  a  hippo  off  certain 

126 


NOISES— SLEEPING    PLACES  127 

low  lying  peninsulae,  among  the  rushes.  When  passing 
such  resorts  in  a  canoe  the  men  always  paddled  very 
quickly,  but  my  experience  was  that  an  unmolested 
hippo  showed  no  resentment  at  being  disturbed,  and  I 
never  had  any  trouble  and  never  shot  at  them.  On  the 
approach  of  the  canoe  the  hippo  would  gradually  sink 
until  only  the  top  of  the  head,  with  ears  and  eyes  and  the 
nostrils,  were  above  water,  when,  in  spite  of  the  seeming 
absurdity,  there  was  a  certain  horsiness  about  him  !  He 
would  watch  the  canoe  suspiciously  until  it  came  too 
close,  and  then  disappear  altogether,  when  the  canoe-men 
would  paddle  furiously  until  we  were  past  what  they 
considered  a  danger  zone.  When  a  frightened  hippo 
comes  up  to  breathe  he  expires  the  used  up  air  with  only 
a  faint  sound,  but  in  the  night  their  loud  noises  can  be 
heard  some  miles  away,  and  are  probably  used  as 
a  call.  It  is  impossible  to  describe  the  noise,  neither 
snorting  nor  grunting  are  completely  descriptive  ;  it  can 
be  imitated  by  making  a  noise  at  the  back  of  the  throat 
while  indrawing  a  breath. 

These  calls  at  night  have  a  fascination  all  their  own  ; 
sometimes,  however,  could  be  heard  other  much  louder  and 
less  pleasing  noises  that  seemed  to  indicate  a  battle  royal, 
perhaps  between  rival  suitors. 

Hippos  have  regular  sleeping  places  in  the  forest  or 
bush  on  the  islands,  from  which  they  may  sometimes  be 
disturbed  in  the  day  time. 

On  Kimmi  Island,  when  with  Fiske  one  day,  I  heard 
him  say,  "  Well,  isn't  this  just  cunning,"  and,  coming  up, 
found  hm  looking  at  the  sleeping  places  of  a  mother  and 
baby  hippo,  where  could  plainly  be  seen  the  imprint  of 
head,  body  and  legs  on  the  dead  leaves,  showing  how  they 
had  slept  side  by  side.  The  little  rocky,  bush  covered 
islet  Rumfua,  of!  the  south  coast  of  Kome  Isle,  was 
evidently  a  favourite  dormitory,  for  there  were  several  bed 
places  among   the  thick  bushes   and  ferns  ;    since  there 


128  MAMMALS 

was  nothing  particularly  tempting  for  them  to  eat  they 
must  have  gone  there  expressly  for  sleeping. 

I  once  found  among  some  reeds  near  the  water's  edge 
a  well  marked  bed  place,  with  a  mud  wallow  beside  it ; 
one  was  reminded  of  a  house  agent's  advertisement, 
"  bath  room  adjoining  "  ! 

Hippos  wander  about  over  the  smallest  islands  ;  thus, 
the  central  conical  grass  clad  hill  of  Isentwa  Isle,  rising 
steeply  from  the  water  to  a  height  of  a  hundred  feet  or 
more,  had  a  definite  track  across  the  top  ;  but  why  they 
should  visit  an  island  apparently  so  unprofitable  from  a 
gastronomic  point  of  view  it  is  difficult  to  say. 

The  wealth  of  vegetation  that  springs  up  in  deserted 
banana  plantations  on  the  islands  is  very  attractive  to 
these  animals,  whose  tracks  always  lead  to  the  plant- 
ations. On  a  very  sandy  stretch  of  shore  on  Damba, 
I  saw  tracks  of  a  large  hippo  with  a  baby,  leading  from 
the  water  into  the  forest,  and  quite  close  by  were  the  same 
tracks  leading  back  into  the  water.  It  was  quite  obvious 
that  on  the  return  journey  the  poor  baby  had  been  very 
tired,  for  when  he  got  on  to  the  soft  sand  he  had  not  lifted 
his  feet  sufficiently  to  clear  it,  and  a  furrow  between  each 
footprint  showed  how  his  weary  toes  had  dragged  over  the 
sand.  However,  he  very  soon  got  into  the  water  for  a 
rest.  It  was  quite  possibly  this  same  mother  that  I  saw 
one  morning  when  on  the  way  to  the  day's  work  on  the 
fly  beach.  As  the  canoe  drew  near  we  saw,  lying  oflE 
shore,  a  large  hippo  lying  on  one  flank  in  the  water,  with 
the  whole  of  the  other  flank  exposed. 

We  naturally  concluded  it  was  a  corpse,  but  as  the 
canoe  came  nearer  there  was  much  difference  of  opinion 
among  the  men  ;  finally,  when  we  came  closer  still,  the 
hippo  proved  to  be  very  much  alive,  for  she  rolled  over 
and  sank,  and  then  we  saw  the  heads  of  two  babies  also 
in  the  water.  None  of  us  had  ever  before  seen  a  hippo 
take  up  this  attitude  in  the  water  ;  it  seems  possible 
that  she  was  giving  her  babies  milk. 


MOTHER   AND   BABY  129 

One  day  in  January  1919,  I  went  across  to  Damba  fly 
beach  from  the  east  end  of  Kome  Isle,  but  as  a  high  wind 
had  raised  a  considerable  sea,  it  was  necessary  to  find  a 
sheltered  spot  for  landing,  and  then  walk  round  to  the 
exposed  beach,  where  the  noise  of  the  waves  and  of  the 
wind  in  the  belt  of  forest  behind  the  beach  drowned  the 
sound  of  footsteps.  Consequently  a  hippo  mother  with 
her  baby  that  was  sleeping  in  the  forest  did  not  take  alarm 
at  first.  I  was  standing  on  the  beach,  observing  the 
changes  that  had  occurred  since  the  last  visit  in  1914, 
when  suddenly  a  loud  snorting  was  heard,  and  the  huge 
beast  rushed  past  me  into  the  water,  closely  followed  by 
the  tiniest  baby  hippo  I  had  ever  seen.  It  bleated  in  a 
most  comical  manner,  rather  reminding  one  of  a  toy, 
and  was  so  small  that  it  was  still  quite  weak,  and  stumbled 
on  to  its  knees  several  times  before  it  reached  the  water. 
Though  so  young  it  was  not  pink,  but  dark  brownish 
grey.  I  was  so  taken  by  surprise  by  their  sudden 
appearance  that  the  chance  of  catching  the  baby  was  lost  : 
but  it  remained  in  shallow  water  just  beyond  the  breaking 
waves,  putting  up  its  nose  at  short  intervals  for  a  breath 
of  air.  The  mother  was  further  away,  evidently  rather 
anxiously  watching  the  fate  of  her  little  one,  and  though 
the  boys  with  me  wanted  to  go  into  the  water  and  catch 
the  baby,  I  thought  it  better  to  say  no,  lest  the  mother 
should  attack. 

This  was  the  same  part  of  Damba  coast,  as  that  where 
a  mother  was  seen  in  the  water  apparently  suckling  her 
young,  as  described  ;  perhaps  it  is  a  favourite  nursery. 

One  night  on  Damba  I  woke  up  hearing  a  curious  noise 
which,  in  my  sleepy  condition,  I  could  not  define  at  first. 
Presently  it  resolved  itself  into  the  grinding  of  teeth,  and 
I  realized  that  a  large  hippo  was  grazing  on  the  choice 
grass  just  by  the  tent.  As  I  was  afraid  he  might  blunder 
into  the  ropes  and  bring  down  the  tent,  I  went  out  with  a 
towel  and  waved  it  vigorously,  and  the  huge  beast  moved 

10 


130  MAMMALS 

off  ;  it  was  a  dark  night,  and  only  a  black  shape  could  be 
seen.  Hippos  are  very  fond  of  lush  grass  which  grows 
along  low  marshy  or  sandy  stretches  of  shore,  and  these 
were  dubbed  "  grazing  grounds,"  for  the  grass  was  always 
kept  short.  A  magnificent  opportunity  of  photographing 
a  grazing  hippo  was  lost  because  a  camera  was  not  to  hand. 
In  company  with  the  fly  boys  I  was  going  down  to  the 
morning's  work  on  the  fly  beach  of  Bugalla.  As  we 
emerged  from  the  bordering  strip  of  forest  there  was  a 
hippo  on  the  sand,  grazing  quite  openly  on  the  grass. 
I  walked  along  the  shore  towards  him  to  see  how  close  he 
would  allow  me  to  come  ;  he  had  his  back  towards  me  but 
turned  round  at  once,  saw  me,  stared,  and  went  on  grazing. 
I  continued  to  approach,  thinking  it  would  be  good  fun 
to  pick  up  a  stick  and  give  him  an  unexpected  blow  from 
behind.  But  his  guardian  angel  was  true  to  his  duty, 
and  when  I  was  within  about  thirty  yards  an  ibis  suddenly 
took  to  wing  with  its  raucous  alarm  cry,  "  Aa-aa-aa." 
The  hippo  turned  round  in  a  fright,  made  an  angry  face 
at  me,  and  rushed  into  the  water,  leaving  me  lamenting. 
I  should  like  to  conclude  my  remarks  on  the  hippo  by  the 
following.  A  new  monthly  journal  was  founded  to  deal 
with  Colonial  interests,  and  a  specimen  copy  of  the  first 
number  reached  me  on  the  islands.  In  it  was  an  account 
of  a  lecture  given  by  some  one  on  Sleeping  Sickness  at 
a  meeting  of  a  photographic  society,  wherein  were  found 
these  astonishing  statements.  The  lecturer  said  it  had  been 
proved  that  the  Tse-tse  could  not  exist  without  a  feed  of 
crocodile's  blood  (!),  and  that  it  was  well  known  that  the 
hippo  had  an  inveterate  habit  of  destroying  crocodiles' 
eggs  (or  was  he  supposed  to  eat  them  ?  My  memory 
fails  on  this  point).  Here,  then,  said  the  lecturer,  is  the 
solution  of  the  problem  of  Sleeping  Sickness  in  a  nutshell. 
Preserve  the  hij)po,  and  he  does  the  rest  !  One  can 
picture  the  establishment  of  "  hippo  hatcheries  "  all 
round  the  lake,  and   schools   where  youngsters  will  be 


MONKEYS  131 

taught  the  difference  in  appearance  between  the  eggs  of 
crocodiles  and  fowls  ! 

But  perhaps  the  lecturer  was  a  humorist  ?  .  .  . 

Monkeys. 

One  species  of  monkey,  a  Cercopithecus,  lives  on  the 
islands,  but  only  on  the  largest  :  they  were  found  on 
Kome,  Damba,  Wema  and  Yempata  out  of  those  that 
were  visited  in  the  group  lying  off  the  north  shore  of  the 
lake,  and  on  Bugalla  and  the  larger  isles  of  the  Sesse 
groujD.  A  very  curious  fact  is  their  presence  on  the  Isle 
of  Nkosi,  which  is  the  southernmost  of  all  the  Sesse  isles, 
quite  small  and  in  a  very  isolated  and  exposed  position  ; 
when  I  visited  this  islet  in  1913  I  distinctly  heard  a 
monkey's  voice,  though  he  was  not  visible  (see  p.  92). 
The  species  is  of  a  common  type :  greenish  grey  in 
colour,  with  black  face  and  a  white  band  across  the  fore- 
head. It  has  been  of  very  great  service  in  the  investigation 
of  Sleeping  Sickness,  since  the  Trypanosomes  which  cause 
that  disease  are  also  pathogenic  to  the  monkey,  which 
can  thus  be  used  as  a  test  for  infected  flies.  Hence  I  had 
one  with  me  on  the  islands  for  this  purpose,  and  also 
two  others  as  pets.  The  "  official  "  one  was  dubbed 
Tommy,  and,  of  course,  had  to  be  kept  tied  up,  as  also 
was  the  older  of  the  two  pets,  named  Wee  Man.  The 
third,  PufRn,  was  a  mere  baby,  and  had  not  yet  become 
sufficiently  mischievous  for  it  to  be  necessary  to  tie  him 
up.  When  I  first  had  Wee  Man  he  was  also  allowed  to 
run  loose,  but  became  so  mischievous  that  when  I  moved 
to  Bugalla  he  was  tied  up. 

Being  in  very  constant  association  with  them,  one  soon 
became  thoroughly  familiar  with  their  behaviour,  their 
moods,  facial  expressions  and  language,  and  soon  found 
oneself  able  to  distinguish  the  meanings  of  their  various 
utterances. 

No  less  than  fourteen  sounds  are  used,  although  some 


182  MAMMALS 

of  them  would  not  be  recognized  as  distinct  by  any  one 
who  had  not  carefully  observed  the  monkeys,  for  they  are 
often  of  the  nature  of  an  alteration  in  inflection,  or  accent, 
rather  than  a  different  word. 

1.  May  be  called  a  "  General  remark,''  and  is  the  com- 
monest expression  ;  used,  seemingly,  when  a  monkey  is 
at  a  loss  what  to  do,  or  when  his  attention  is  attracted 
by  something,  or  when  another  monkey  comes  to  him, 
etc.,  etc. 

2.  Recognition. — A  slight  modification  of  No.  1  was  used 
by  Wee  Man  whenever  he  caught  sight  of  my  servant, 
of  whom  he  seemed  particularly  fond.  Often  I  would 
hear  this  expression  and,  looking  out,  would  see  the  man 
walking  about  a  little  way  away,  and  so  in  time  came  to 
know  what  this  sound  meant,  for  it  was  never  used  on 
any  other  occasion.     It  may  be  expressed  by  "  Wok." 

3.  Eagerness. — Another  modification  of  No.  1  indicated 
eagerness  ;  as,  for  example,  when  the  monkey  saw  some 
one  bringing  a  grasshopper  which  he  particularly  desired. 

4.  Alarm  was  expressed  by  still  another  modification  of 
No.   1,  and  had  two  forms  : 

(a)  For  a  bird  of  prey  overhead,  very  unmistakable 

and  emphatic. 
(6)  For  a  thunderstorm,  or  a  bush  fire,  which  they 

dread  very  much. 

5.  Excitement,  as  when  a  monkey  sees  a  boy  chasing 
a  fowl,  or  two  boys  in  play  chasing  one  another.  This  is 
also  derived  from  No.  1.  I  have  heard  one  of  the  monkeys 
repeatedly  make  this  noise  when  he  saw  a  fish  eagle  chasing 
another  away  from  its  private  fishing  ground.  He  took 
the  greatest  interest  in  the  occurrence,  watching  the  eagles 
as  they  soared  around,  and  being  unable  to  restrain  his 
excitement  when  one  swooped  down  on  the  other. 

6.  Rage. — A  quite  unmistakable  sound,  possibly  con- 
nected with  5. 


WEE    MAN    CHOOSING    A   GRASSHOPPER    FROM    THE   BOX. 
Puffin,  behind,  has  had  his. 


WEE    MAN    (right)    AND   TOMMY    TAKING    GRASSHOPPERS. 


To  face  p.  132^ 


MONKEY  LANGUAGE  133 

7.  Pai7i. — A  kind  of  squeak. 

8.  Cry  for  help. — A  high-pitched  squeak.  Wee  Man  used 
to  make  this  as  a  youngster  when  he  became  inextricably 
entangled  in  his  rope. 

9.  Melancholy. — A  very  distinct,  long-drawn  wail, 
sometimes  heard  in  the  forest,  presumably  indicating  that 
the  monkey  had  become  separated  from  the  troop.  A 
monkey  seen  in  the  act  of  crying  thus  has  a  most  lugu- 
brious appearance ;  the  mouth  is  held  in  a  peculiar 
fashion  and  one  quite  expects  to  see  tears  rolling  down 
the  cheeks. 

10.  Hunting  Call. — One  of  the  most  distinct  sounds  in 
the  monkey  tongue.  When  a  troop  is  searching  the  trees 
for  food  in  the  forest  an  old  male  sits  in  a  very  conspicuous 
tree  top  and  utters  a  series  of  barking  noises  which  can  be 
most  nearly  imitated  by  repeating  very  rapidly  "  Kubba- 
kubba-kubba."  To  this  the  junior  members  reply  by 
high-pitched  squeaks,  and  the  whole  troop  is  thus  enabled 
to  keep  together,  as  the  total  amount  of  noise  produced 
is  considerable. 

11.  Dislike. — A  short,  expressive  word,  which  may  be 
represented  by  saying  beneath  one's  breath  the  first  two 
letters  of  the  word  "  come." 

12.  Intense  dislike  and  fear. — The  last  mentioned  sound 
is  repeated  very  rapidly  and  with  great  energy  when  a 
monkey  sees  a  snake,  or  anything  that  seems  to  savour  of 
a  reptile. 

13.  A  "  baby  "  noise,  only  made  by  young  monkeys 
when  they  have  been  frightened  or  hurt  and  run  for  comfort 
to  be  cuddled  by  their  mothers  or  friends.  It  can  be 
represented  by  the  noise  "  Qurra-qurra-qurra-qurra " 
repeated  beneath  one's  breath. 

Having  been  for  months  in  close  association  with  the 
pet  monkeys,  I  found  their  different  natures  extremely 
interesting,  and   they  were   most  charming  companions, 


184  MAMMALS 

but  it  was  necessary  to  keep  them  tied  up  owing  to  their 
mischievous  dispositions. 

At  one  time,  when  very  young,  Wee  Man  had  been 
allowed  to  run  loose,  and  whenever  I  left  the  house  he 
would  be  unable  to  resist  the  temptation  of  working  havoc 
among  papers  or  anything  else  that  took  his  fancy  which 
he  could  destroy,  although  he  knew  quite  well  he  would 
be  punished,  and  showed  it  by  his  guilty  demeanour  when 
I  returned.  At  this  time  he  would  frolic  around  the 
huts  of  the  canoe-men  when  they  were  away,  and  make 
little  holes  through  the  grass  walls,  so  that  he  could,  if  chased 
when  the  time  came  to  tie  him  up  for  the  night,  dodge 
in  and  out  of  the  huts.  It  was  a  great  game  every  evening 
to  try  and  find  him,  and  if  he  managed  to  hide  himself 
away  and  go  to  sleep  before  he  was  found,  it  was  considered 
that  he  had  won  the  game  ;  and  he  did,  quite  often  ! 
Mischief  was  a  very  marked  feature  of  the  monkeys'  games 
with  each  other,  which  were  delightful  to  watch.  One 
would  be  sitting  on  the  bar,  a  couple  of  feet  above  the 
ground,  his  tail  hanging  down,  and  another,  with  a 
broad  grin  on  his  face,  would  steal  up  and,  seizing  the  tail 
with  both  hands,  tug  furiously  in  the  endeavour  to  bring 
down  the  other,  who,  quite  appreciating  the  joke  and  also 
grinning,  would  cling  on  with  all  his  might. 

They  were  of  a  very  affectionate  disposition,  and  if 
one  was  beaten  or  threatened  the  other  would  do  its 
utmost  to  bite  the  enemy,  shrieking  with  rage  the  while. 
The  baby  Puffin,  on  Bugalla,  was  not  tied  up,  and 
occasionally  got  into  mischief  in  the  house,  when  I 
chased  him  out  with  threatening  gestures.  He  would 
at  once  run  to  the  others,  who  would  receive  him 
anxiously  and  carefully  examine  him  to  see  what  damage 
had  been  sustained,  while  he  made  the  baby  noise  to  which 
they  responded. 

When  the  three  settled  down  to  sleep  for  the  night, 
all  cuddled  together,  they  would  give  each  other  a  long 
kiss,  lip  to  lip  ! 


WEE    MAN    BEING    RUDE   TO   A   TORTOISE. 


TOMMY    (LEFT)    AND   WEE    MAN    IN    AN    INTERVAL    OF    A    GAME. 

To  face  p.  i3». 


I 


MONKEY  AND    TORTOISE  135 

But  their  affection  for  each  other  never  went  to  the 
lengths  of  unselfishness  as  regards  food  ;  if  choice  were 
given,  a  monkey  would  of  course  take  the  largest  piece, 
but  very  often  afterwards  would  drop  that  and  endeavour 
to  take  from  the  other  the  piece  which  he  had  himself 
passed  over.  In  fact,  their  maxim  seems  to  be  "  the 
other's  piece  is  always  better  than  mine  "  ! 

Wee  Man  was  the  most  intelligent  of  the  three,  and  had 
a  more  capable-looking  head.  When  his  rope  became 
very  much  entangled  with  that  of  Tommy,  he  would  look 
at  the'  tangle  for  a  while  and  then  deliberately  try  to 
disentangle  it  by  picking  up  a  loop  and,  as  it  were,  un- 
threading himself  by  walking  through  it.  Often,  if  the 
tangle  was  a  simple  one,  he  would  succeed,  but  if  the  first 
method  was  not  successful  he  would  try  walking  through 
the  loop  in  a  reverse  direction.  Tommy,  however,  though 
he  might  make  futile  attempts,  never  succeeded,  and  seemed 
to  do  it  mechanically  because  he  had  seen  Wee  Man  do 
it.  This  is  the  only  instance  I  ever  saw  of  the  reputed 
imitativeness  of  a  monkey.  A  certain  intelligence  was 
also  shown  in  the  recognition  of  zoological  afiinity.  The 
noise  made  for  a  snake  has  already  been  described,  and 
the  same  was  also  made  for  a  fish  ;  and,  one  day,  having 
found  a  tortoise,  I  brought  it  back  to  see  what  Wee  Man 
would  say  to  it. 

At  first  the  tortoise  withdrew  itself  within  the  shell  : 
Wee  Man  came  down  to  look  very  cautiously  at  it, 
intensely  curious  and  interested,  but  when  it  put  its  head 
out  he  hastily  retreated  to  his  perch  with  loud  utterance 
of  the  snake  noise.  When  it  began  to  walk  he  could  not 
restrain  his  excitement,  and  danced  round  and  round  it, 
chattering,  though  keeping  at  a  safe  distance.  I  am  quite 
sure  that  this  was  the  first  tortoise  he  had  ever  met,  for 
he  had  been  a  captive  ever  since,  as  a  baby,  he  was  clinging 
to  his  mother. 

On  Bugalla  Island,  where  there  was  much  open  grass 


136  MAMMALS 

land  as  well  as  clumps  of  bush  and  continuous  forest, 
when  walking  in  the  evening  I  often  came  across  a  troop 
of  monkeys  among  the  long  grass  hunting  for  grasshoppers, 
which  are  a  great  delicacy.  A  monkey  would  walk  slowly 
and  intently  through  the  grass  until  a  grasshopper  took 
to  flight  just  in  front  of  him,  when  with  a  quick  snatch 
he  would  catch  it  in  his  hands.  The  monkeys  always  bit 
off  the  head  first,  and  then  the  powerful  hind  legs,  if  the 
grasshopper  kicked  much,  and  the  rest  was  eaten  at  leisure. 
Even  the  largest  Acrididae,  three  or  four  inches  long,  with 
formidable  spines  on  the  hind  legs,  were  eaten  with  gusto. 
It  always  made  me  think  of  a  man  eating  a  live  lobster, 
shell,  legs  and  all,  and  not  one  only,  but  half  a  dozen  in 
succession. 

I  once  saw  a  small  young  monkey  in  a  patch  of  papyrus 
reed,  apparently  hunting  for  insects.  He  climbed  up  one 
of  the  tall  stems,  but  just  as  he  reached  the  top  it  slowly 
bent  over  with  his  weight  and  he  disappeared  from  view. 
Fortunately  for  him  the  papyrus  was  not  growing  in 
water. 

In  Damba  forest  I  came  across  a  troop,  on  the 
ground,  very  busily  engaged  in  turning  over  dead  leaves, 
looking  for  insects.  So  pre-occupied  were  they  that  I  was 
enabled  to  creep  up  quite  close  and  watch  them  before 
one  looked  up  and  gave  the  alarm. 

The  captive  monkeys  were  always  ready  to  eat  insects, 
and  if  a  species  was  offered  of  which  they  were  afra  d, 
such  as  a  large  bee  or  powerful  ground  beetle,  they  would 
paw  it  on  the  ground  with  rapid  strokes  of  one  hand  after 
another  until  it  was  disabled,  when  it  would  be  quickly 
picked  up  and  nipped  between  the  teeth,  to  be  subsequently 
eaten  at  leisure,  if  desirable. 

One  evening  on  Bugalla  I  surprised  a  troop  hunting  in 
the  long  grass  some  little  distance  away  from  the  nearest 
trees,  to  which  they  hastily  retreated.  A  tiny  youngster 
who  had  been  put  down  by  his  mother  was  unable  to 


i^ 


A  BABY  MONKEY  137 

escape  and  took  refuge  in  a  small  bush,  where  I  easily- 
caught  him — a  dear  little  fluffy  beast,  all  head  and  tail, 
that  sat  easily  on  the  palm  of  my  hand.  Unfortunately 
for  him  the  bush  was  occupied  by  a  species  of  very  power- 
fully biting  ant,  and  when  I  got  him  the  poor  little  monkey 
was  being  severely  bitten  by  the  ants  deeply  embedded 
in  his  fur.  So  I  took  him  on  my  knee  and  soothed  him 
while  I  picked  out  the  ants  with  forceps,  the  youngster 
sitting  quietly  as  if  my  attempts  at  the  "  cuddling  noise  " 
were  quite  intelligible.  His  parents  and  friends  on  the 
neighbouring  trees  were  naturally  much  alarmed  for  his 
safety,  and  danced  up  and  down  in  impotent  rage,  with 
shrieks  of  defiance  that  could  plainly  be  interpreted  as 
**  Hurt  him  if  you  dare  !  "  When  I  had  freed  him  from 
the  ants  and  smoothed  him  down,  I  showed  him  his  friends 
on  the  trees  and  put  him  down  in  the  grass  ;  he  ran  off 
more  or  less  in  the  right  direction,  and  I  could  see  him 
thoroughly  overhauled  by  his  parents,  anxious  to  see 
what  damage  had  been  inflicted,  and  then  conveyed  by 
the  whole  party  into  the  forest.  These  very  young 
monkeys  are  carried  about  beneath  the  belly  of  the  mother, 
their  limbs  embracing  her  body,  and  hands  and  feet  firmly 
grasping  the  hair  on  her  back. 

The  Sitittunga. 

The  only  antelope  on  the  islands  which  I  visited  is  the 
Situtunga  {Limnotragus  or  Tragelaphus  spekei),  known  to 
the  natives  of  the  islands  as  "  Enjobe."  This  interesting 
buck  was  discovered  by  J.  H.  Speke  in  1862  in  the  Karagwe 
district,  south  of  the  Kagera  river.  He  gives  it  the  native 
name  of  "  Nzoe  "  and  says  of  it :  "It  proved  to  be  closely 
allied  to  a  water-boc  found  by  Livingstone  on  the  Ngami 
Lake,  but  instead  of  being  striped  was  very  faintly 
spotted,  and  so  long  were  its  toes  it  could  hardly  walk  on 
the  dry  ground  ;  whilst  its  coat,  also  well  adapted  to  the 
moist  element  it  lived  in,  was  long,  and  of  such  excellent 


188  MAMMALS 

quality  that  the  natives  prize  it  for  wearing  almost  more 
then  any  other  of  the  antelope  tribe.  The  only  food  it 
would  eat  were  the  tops  of  the  tall  papyrus  rushes  ;  but 
though  it  ate  and  drank  freely,  and  lay  down  very 
quietly,  it  always  charged  with  ferocity  any  person  who 
went  near  it." 

The  Enjobe  is  about  the  size  of  a  donkey.  The  male  has 
beautiful  horns,  long  and  spirally  twisted,  with  almost 
translucent  tips  ;  the  females  are  hornless.  The  colour 
varies  considerably  ;  the  young  males  are  bright  foxy 
red,  marked  with  white,  adult  males  are  darker  brown, 
but  I  have  seen  an  adult  female  of  the  same  colour, 
although  typically  they  are  more  brightly  coloured  like 
the  young  male. 

This  antelope  with  its  elongate  hooves  is  well  known  to 
haunt  swamps  for  which  its  deeply  cleft  feet  are  suitable, 
in  the  same  manner  as  are  those  of  the  reindeer  for  snow 
or  of  the  camel  for  sand. 

It  is  mentioned  in  books  as  spending  its  days  immersed 
in  water  among  papyrus,  etc.,  and  is  apparently  considered 
as  an  animal  confined  to  swamps.  On  the  islands,  however, 
it  is  a  creature  of  different  habits,  possibly  owing  to  the 
entire  absence  of  enemies,  human  or  otherwise,  from  which 
on  the  mainland  it  takes  refuge  in  swamps.  Indeed,  it  now 
behaves  much  like  its  close  ally  the  bushbuck,  called 
"  Engabi  "  by  the  natives.  On  some  of  the  islands  which 
it  inhabits  there  are  no  papyrus  swamps,  and  during  the 
day  time  I  often  disturbed  Enjobe  from  their  resting 
places  in  the  forest  belt  near  the  water. 

In  the  evening  they  could  be  seen  coming  out  on  to  the 
open  grass  covered  spaces  and  browsing  on  bushes, 
especially  "  Oluzibaziba,"  the  Euphorbiaceous  Alchornea 
chordata,  of  which  they  eat  the  young  tips. 

The  bushbuck  may  well  have  had  similar  habits  on  the 
larger  islands  in  former  days  until  it  was  exterminated. 
The  Situtunga,  on  the  other  hand,  could  have  taken  refuge 


SITUTUNGA  189 

in  the  water,  as  it  now  docs  on  the  mainland.  Since  the 
removal  of  the  islanders,  however,  which  was  completed 
in  1909,  its  habits  have  become  changed,  and  it  is  multi- 
plying very  quickly  in  the  absence  of  all  enemies. 

Major  R.  Meinertzhagen,  F.Z.S.,  visited  Bugalla  from  a 
steamer  during  the  war  in  October  1915,  and  examined 
several  Situtunga,  finding  interesting  differences  from  the 
mainland  type  ;  the  horns  diverged  more  widely.  But 
the  specimens  from  the  much  smaller  and  more  isolated 
islet  of  Nkosi  showed  further  deviation  to  such  an  extent 
that  they  are  given  sub-specific  rank.^ 

The  feet  show  a  slight  return  from  the  specialized 
narrow  hoof  of  the  type,  for  in  the  Nkosi  animals  the 
hooves  are  proportionately  broader,  and  in  a  young  animal 
were  "  no  longer  than  one  would  expect  to  find  in  a  young 
bushbuck  of  his  age." 

The  horns  also  are  more  like  those  of  a  bushbuck,  and 
the  colour  of  the  adult  male  was  noted  as  "  of  a  uniform 
dull  mouse  colour  and  not  a  dark  brown  "  ;  the  animals 
are  also  larger  than  the  typical  mainland  forms. 

It  is  remarkably  interesting  that  this  change  in  structure 
can  be  noted  together  with  the  change  of  habits  ;  the 
Nkosi  animals  are  losing  the  high  specialization,  correlated 
with  the  peculiar  mode  of  life  among  swamps,  which 
characterizes  the  Situtunga  discovered  by  Speke. 

The  Situtunga  could  frequently  be  heard  barking  at 
night,  the  call  being  somewhat  like  that  of  the  bushbuck 
but  distinct  from  it,  rather  more  muffled  and  less  dog- 
like. 

The  following  may  be  cited  as  evidence  of  the  effect  of 
the  removal  of  all  inhabitants  from  the  islands. 

Nsadzi,  the  long  narrow  isle  lying  due  south  of  Entebbe, 
was  free  from  this  antelope  when  inhabited,  according  to 
native  testimony,  although  the  densely  forested  eastern 
end  provides  ample  shelter.     When  I  visited  it  in  1914  with 

^  Proceedings  of  the   Zoological  Society,   June,    1916,   pp.    375-81. 


140  MAMMALS 

Fiske  he  found  footprints,  and  later  on  I  found  abundant 
evidence  that  Situtunga  at  least  visit  Nsadzi.  I  have 
also  found  bushes  browsed  by  them  on  Ngamba,  between 
Nsadzi  and  Kome,  on  which  latter  large  island  they  abound, 
so  that  it  is  probable  they  had  crossed  to  Nsadzi  from 
Kome,  using  Ngamba  as  a  stepping  stone,  for  it  is  well 
known  that  they  swim  readily.  The  importance  of  these 
movements  from  the  point  of  view  of  Sleeping  Sick- 
ness has  already  been  discussed  in  Chapter  II,  pp. 
28-29. 

The  smallest  island  on  which  I  have  seen  Enjobe  is  the 
previously  mentioned  Nkosi,  lying  to  the  extreme  south 
of  the  Sesse  archipelago,  and  very  exposed.  Several  were 
seen  there  on  a  visit  (see  p.  91),  and  areas  of  grass 
were  kept  close  cropped  by  their  grazing.  It  seems 
almost  certain  that  they  must  swim  to  and  from  this 
tiny  island  from  the  larger  isles  to  the  north. 


Otters. 

Otters  abound  in  the  lake,  as  might  be  expected,  and 
one  is  glad  to  feel  that  their  numbers  are  steadily 
increasing  now  that  they  can  no  longer  be  destroyed  for 
their  skins  by  the  islanders.  There  can  be  few  animals 
more  beautiful  than  otters  in  the  water  ;  they  are  so 
lithe  and  graceful  and  sleek,  and  so  full  of  the  joie  cle 
vivre.  I  remember  well  one  very  hot  day  when  I  was 
visiting  the  little  islet  Kizima.  Looking  down  from  the 
top  of  a  little  cliff  into  the  water  I  saw  below  some  half 
dozen  otters  sporting  in  the  water  and  tying  themselves 
into  knots,  but  in  a  very  leisurely  way,  as  if  it  was  too  hot 
for  much  exertion.  On  another  occasion  off  Tavu  Isle 
there  were  about  a  dozen,  fishing  and  playing  with  their 
catches  in  a  very  delightful  sportive  mood  ;  throwing 
the  fish  up  into  the  air  and  catching  it  again.  One  lay 
on  his  back  in  the  water  in  a  most  ludicrous  attitude, 


OTTERS— LEOPARD  141 

with  a  fish  in  his  mouth  and  hind  feet  and  tail  sticking 
up  out  of  the  water. 

The  size  of  fish  that  otters  can  tackle  is  very  surprising. 
On  Ziro  Isle,  in  1919,  I  saw  the  remains  of  a  very  large 
Silurid  fish,  which  had  evidently  been  dragged  up  on  to  a 
rock  high  above  water  by  one  or  more  otters  which  had 
eaten  all  except  the  shoulders  and  the  large  flat  bony  head, 
measuring  12  by  9  inches.  This  part  that  remained  was 
taken  to  camp,  and  was  found  to  weigh  twenty  pounds  ! 
So  the  fish,  which  the  natives  called  "  Akasonzi,"  would 
probably  have  weighed  forty  pounds  at  least.  It  was 
the  largest  one  the  natives  had  ever  seen. 

The  otters  in  Kingsley's  Water  Babies  are  described  as 
making  a  queer  chorus  of  squealing  noises,  but  I  never 
heard  a  sound  that  could  be  ascribed  to  an  otter,  even 
at  night,  save  when  one  comes  up  to  breathe  close  by, 
and  emits  a  short  grunt  before  diving  again. 

Leopard. 

The  larger  carnivora  were  not  met  with  on  the  islands 
save  for  one  exception.  On  Kibibi,  in  January  1919,  fresh 
spoor  of  a  leopard  was  seen  on  the  wet  sand  on  two  succes- 
sive visits  nearly  a  week  apart.  The  leopard  must  have 
swum  from  the  coast  of  the  mainland  across  at  least  2|  miles 
of  open  water.  (See  map.)  The  spoor  was  seen  very  fresh 
on  both  January  17th  and  22nd,  there  having  been  heavy 
rain  between  the  two  visits.  So  it  would  seem  that  the 
animal  was  there  all  the  time,  although  there  cannot  have 
been  much  food  for  it.  On  Kibibi  there  are  neither  buck 
nor  monkej^s,  and  there  are  no  game  birds  (save  an 
occasional  bustard,  quail,  or  forest  francolin)  on  any  island 
that  I  have  visited.  Presumably  the  leopard  managed  to 
catch  fish  or  ate  crabs  that  it  found  on  the  beach  ! 

Mongoose. 
Animals  of  the  civet  cat  tribe  ( Viverridae)  were  not  often 


142  MAMMALS 

met  with  on  the  islands,  and  then  only  on  the  very  largest. 
A  pair  of  genets  was  once  seen  on  Kome,  their  long  snaky 
bodies,  with  spotted  coats,  and  short  legs  being  quite 
unmistakable,  even  though  they  were  only  seen  darting 
away  in  alarm. 

On  Damba  one  day  in  1911,1  had  a  delightful  experience. 
I  was  sitting  quietly  by  a  clump  of  bushes,  watching  for 
bee-eaters  at  the  edge  of  the  forest,  some  30  yards  away, 
and  keeping  as  motionless  as  possible.  A  beautiful 
mongoose,  of  a  rich  red-brownish  green  colour,  with  tail 
all  fluffed  out,  walked  across  a  little  grassy  bay  in  the  edge 
of  the  forest,  very  full  of  vigour,  but  not  in  a  hurry,  and 
disappeared  again  among  the  bushes.  Shortly  afterwards 
there  was  heard  an  agitated  quacking  and  cackling  from 
the  jungle  on  my  left,  and  an  Egyptian  goose  came  across 
the  grass  in  front  of  me,  and  only  a  few  yards  away, 
followed  by  the  mongoose. 

The  goose  fluttered  along  making  a  great  fuss,  apparently 
just  keeping  out  of  reach  of  the  pursuer.  It  seemed  to 
me,  however,  that  the  mongoose  was  not  exerting  himself 
very  much,  as  if  he  thought  that  the  obviously  disabled 
bird  in  front  must  very  soon  fall  an  easy  prey.  The  two 
passed  into  the  jungle  on  my  right,  and  the  deluded 
mongoose  lost  his  prey.  Shortly  afterwards  I  saw  him 
again,  walking  across  the  little  bay,  but  the  ruse  had 
been  successful ;  the  goose  had  drawn  him  away  from  a 
brood  of  babies,  and  while  he  had  been  chasing  one  parent 
the  other  had  led  the  goslings  away  in  another  direction, 
and  I  could  see  them  swimming  away  to  a  marshy  bit  of 
land  where  they  were  safe  for  the  time.  But  a  few  days 
later  I  saw  that  the  number  of  goslings  was  much 
diminished,  so  the  mongoose  may  have  been  more  success- 
ful a  second  time,  knowing  the  trick  that  had  been  played 
on  him. 

It  was  very  interesting  to  see  this  old,  old  trick  actually 
succeed. 


A  FAVOURITE  HAUNT  OF  SITUTUNGA  ON  BUGALLA. 

They  feed  in  the  evening  on  the  bushes  at  the  edge  of  the  forest  belt  which  slopes  steeply  to 

the  water. 

By  permission  of  the  Royal  Society  and  the  Controller,  H.M.  Stationery  Office. 


A    BAT   CAUGHT   ON    TENT   AT  JINJA. 


To  (ace  p.  142, 


BATS  143 


Bats. 


Bats  abound  among  the  dense  vegetation  of  the  old 
banana  plantations,  and  may  often  be  seen  in  the  day 
time  hanging  from  the  midrib  of  a  banana  leaf.  The 
caves  found  on  Kimmi,  Damba  and  other  isles  shelter 
numbers  of  the  smaller  species,  named  "  Akawundo  "  by 
the  natives.  I  shot  a  few  of  these  one  morning  in  order 
to  investigate  the  contents  of  their  stomachs,  but  although 
it  was  only  about  9  o'clock,  their  stomachs  were  quite 
empty.  The  noise  reverberating  in  the  cave  was  so 
distasteful  to  the  bats  that  for  a  long  while  they  did  not 
return  ;  possibly  their  instinct  warned  them  that  such 
a  noise  could  only,  in  the  experience  of  the  race,  have 
been  caused  by  rock  falls  making  the  cave  unsafe. 

I  had  a  curious  experience  at  Jinja  one  evening  in  1910. 
Hearing  an  animal  scrambling  about  over  the  roof  of  the 
tent  and  being  unable  to  drive  it  away  by  repeatedly 
striking  the  canvas,  I  went  out  with  a  lantern  and  found  to 
my  surprise  that  it  was  not  a  mouse  but  a  bat,  whose 
photograph  is  reproduced  (p.  142).  It  was  a  more  active 
walker  than  others  that  I  have  encountered,  and  seemed 
quite  unwilling  to  fly.  It  had  possibly  been  crawling 
about  on  the  roof  after  insects  that  were  attracted  to  the 
light. 

The  much  larger  frugivorous  bats,  commonly  called 
"  Flying  Foxes,"  and  by  the  natives  "  Ekinyira," 
occasionally  gathered  together  in  great  numbers,  possibly 
for  breeding  purposes.  This  was  first  noticed  on  Bunyama 
in  January  1912,  and,  later,  on  Ngamba  in  March  and 
April  1914. 

They  assemble  among  dense  creepers,  and  may  be  heard 
chattering,  and  also  smelt,  before  a  landing  is  made. 

When  disturbed  they  made  a  prodigious  noise,  scrambling 
about  and  squeaking  loudly  before  taking  to  flight  and 
circling  round  looking  for  a  new  resting  place. 


144  MAMMALS 

Although  I  visited  Ngamba  every  week  between  March 
and  August  1914,  I  did  not  find  these  bats  congregated 
after  April. 

Since  the  expanse  of  wings  is  about  two  feet,  they  look 
large  creatures  in  flight,  and  the  beating  of  the  wings 
makes  a  considerable  noise  when  one  disturbs  a  large 
congregation. 

At  night  the  "  Ekinyira  "  in  the  forest  keeps  up  a  most 
insistent  loud  noise  at  intervals  of  about  a  second.  For  a 
long  while  I  thought  it  was  produced  by  a  large  frog. 
It  is  a  sharp  note,  between  a  high-pitched  croak  and  a 
grunt,  with  something  of  a  bark  in  it.  It  may  be  heard 
from  shortly  after  sunset  for  hours  on  end,  and,  if  one 
awakes  in  the  middle  of  the  night,  may  still  be  heard 
coming  from  the  same  spot ! 


CHAPTER  VIII 

BIRDS 

Ornithology  is  a  subject  to  which  I  have  devoted  less 
time  and  observation  than  entomology,  so  that  I  have  not 
so  much  to  say  about  birds  because  of  my  ignorance  of 
their  identity. 

In  writing  this  chapter  I  have  been  much  indebted  to 
Mr.  C.  F.  Belcher,  of  Uganda,  who  has  kindly  given  me 
the  scientific  names  of  such  species  as  are  dealt  with, 
and  also  some  of  the  native  names  which  I  had  not  found 
out. 

The  arrangement  and  nomenclature  is  according  to 
Reichenow. 

Perhaps  the  most  striking  ornithological  feature  of  the 
islands  is  the  difference  of  their  fauna  from  that  of  the 
adjoining  coast  of  the  mainland. 

I  am,  of  course,  only  speaking  of  the  islands  that  I 
know  weU,  those  lying  parallel  to  the  north  coast  of  the 
lake  between  Entebbe  and  Jinja,  and  Bugalla  in  the 
north-west  corner  of  the  lake.  The  differences  that  have 
been  noted  will  be  mentioned  as  the  various  groups  are 
alluded  to. 

Gulls  are  some  of  the  first  birds  noticed  by  the  traveller 
on  the  lake,  and  while  I  was  on  Damba  Island  in  1911 
I  saw  a  good  deal  of  them.  Some  low  rocks  in  the  water 
lay  off  the  point  on  which  I  was  camped,  and  for  some 
reason  these  were  a  favourite  resort  of  gulls  and  many 
other  birds,  so  that  there  was  a  bigger  collection  there 
than  at  any  other  place  I  know  among  the  islands. 

11  i« 


146  BIRDS 

At  least  two  species  of  gull  (Larus  fusciis  and  cirrho- 
cephalus),  one,  larger,  with  black  back,  the  other  grey, 
were  always  chattering  and  screaming  there,  together 
with  terns,  cormorants,  darters,  pratincoles,  sandpipers, 
goliath  herons  and  other  herons,  amongst  them  a 
magnificent  snow  white  species  seldom  seen,  but  there  in 
some  numbers  (?  Herodias  alba),  white  egrets  and  the 
white  egret-like  buff  backed  heron,  the  open-bill  and 
another  stork,  Egyptian  geese,  and  sometimes  ibises, 
either  the  black  and  white  sacred  species  or  the  dark 
greenish  black  Hagedash  ibis. 

The  gulls  are  much  more  noisy  before  stormy  weather, 
and  were  quite  useful  as  weather  prophets.  It  seemed 
to  me,  also,  that  one  did  not  see  much  of  the  terns 
except  in  windy  weather,  when  they  were  noticeable  flying 
about  close  to  the  land.  Gulls  are  known  to  the  natives 
as  "  Enkobyo-kobyo,"  and  terns  (Hydrochelidon  leucoptera) 
by  a  name  that  sounded  like  "  Akalerwe,"  but  I  would 
not  be  certain  of  its  correctness.  Two  species  were  noted. 
It  often  seemed  curious  to  me  that  I  never  met  with  the 
nests  of  gulls  on  the  coasts  of  the  islands  ;  possibly  they 
do  not  breed  close  to  the  water. 

They  feed  on  dead  fish  and  other  flotsam  on  the  surface 
of  the  lake,  but  one  has  been  seen  in  close  attention  on  a 
number  of  cormorants  that  were  fishing  in  shallow  water. 
When  one  came  up  to  the  surface  with  a  wriggling  fish 
in  its  mouth  the  gull  swooped  down  upon  it,  and  in  self 
defence  the  cormorant  had  to  dive  again  with  the  fish 
uns wallowed.  This  happened  repeatedly  until  the  passing 
of  the  canoe  disturbed  the  birds,  so  that  I  could  not  see 
whether  the  gull  had  made  the  cormorant  give  up  its 
prize. 

Cormorants  naturally  abound  among  the  islands,  and 
soon  become  familiar  sights.  One  is  much  puzzled  by  the 
variety  of  markings  of  the  larger  birds  {Phalacrocorax 
lucidus).     They  may  be  black  without  any  white,  or  with 


CORMORANTS  147 

snow  white  throat  and  breast,  with  or  without  a  round 
white  patch  on  the  side  just  behind  the  angle  of  the 
wing. 

A  smaller  species  (Phalacrocorax  africanus)  is  all  black, 
and  nearly  always  very  ragged  looking  ;  indeed,  one  cannot 
feel  any  affection  for  the  cormorants,  they  are  smelly 
and  unattractive.  Natives  call  the  smallest  specimens 
"  Semirindi,"  the  larger  ones,  without  much  white, 
"  Ensogwe,"  and  the  largest  white  breasted  specimens  are 
named  "  Engadala,"  but  most  natives  class  them  all, 
together  with  the  darters,  as  "  Ensogwe." 

These  birds  have  their  regular  "  rookeries  "  where  they 
breed  year  after  year,  so  that  the  ambatch  trees  on  which 
they  continually  perch  and  build  their  loose  nests  of 
sticks  become  flattened  down  and  often  look  very  unhappy. 
The  birds  when  sitting  on  the  nests  have  a  curious  habit 
of  rapidly  moving  in  and  out  the  loose  skin  of  the  "  chin," 
in  somewhat  the  same  way  as  a  fowl  when  gasping  for 
breath  in  very  hot  weather.  It  is  possibly  due  to  the 
same  cause  in  both  cases,  as  the  cormorants  sit  on  the 
nests  exposed  to  the  full  blaze  of  the  sun. 

I  first  noticed  this  when  watching  the  nesting  birds  on 
the  islands  of  the  Nile  at  Jinja,  below  the  falls.  Cor- 
morants abound  here,  and  swim  fearlessly  about  amidst 
the  turbulent  eddies  immediately  below  the  actual  cataract, 
where  one  would  think  they  must  be  beaten  against  the 
rocks. 

About  sunset  large  numbers  of  these  birds  return  from 
the  lake,  flying  up  the  narrow  gulf  until  they  reach  the 
falls  where  the  gulf  becomes  the  river.  Here,  in  1910, 
I  often  noticed  a  very  curious  trick  of  flight. 

When  the  leading  bird  of  the  flock  arrived  over  the 
falls  it  would  suddenly  close  the  right  wing  so  that  it 
fell  down  sideways  for  some  twenty  feet  or  so,  to  recover 
with  perfect  ease  and  resume  its  former  steady  flight. 
Often  several  would  do  this  in  succession,  as  if  playing 


148  BIRDS 

follow-my-leader,  but  I  have  never  seen  this  trick  played 
anywhere  else. 

Occasionally  a  single  bird  winging  its  way  home  utters 
a  rhythmic  croak  at  intervals,  strongly  suggesting  a  man 
loudly  panting  for  breath.  They  are  not  exactly  songsters  ; 
their  noises  are  more  of  the  nature  of  quackings  than 
anything  else.  Except  for  the  trick  above  mentioned  one 
does  not  see  much  sign  of  the  joie  de  vivre  in  cormorants ; 
they  seem  to  find  life  a  serious  business,  and  have  to  work 
hard  for  a  living.  When  resting,  and  possibly  digesting, 
on  the  branches  of  their  favourite  trees,  they  often  spread 
their  wings  out  on  each  side  of  the  body,  as  if  they  felt 
the  heat,  or  were  holding  them  out  to  dry,  although  so 
oily  are  their  feathers  that  they  cannot  really  get  wet. 
It  always  amused  the  canoe-men,  when  we  were  going 
along,  to  see  one  of  these  birds  suddenly  appear  on  the 
surface,  often  with  a  wriggling  fish  in  its  beak,  hastily 
look  round,  and  either  dive  again  or  take  to  flight.  Being 
heavy  birds,  they  have  to  paddle  their  feet  along  the 
surface  for  some  distance  before  their  wings  have  developed 
enough  momentum  to  lift  them  up. 

Closely  allied  to  the  cormorants,  and  grouped  with 
them  by  the  natives  under  the  name  "  Ensogwe,"  are  the 
snaky-necked  Darters  (Anhinga  rufa),  often  erroneously 
called  Divers,  which  name  belongs  properly  to  the 
marine  Colymbi. 

These  are  not  nearly  so  abundant  as  the  cormorants, 
from  which  they  are  easily  distinguished  by  the  much 
smaller  head  and  very  long  slender  neck,  bent  upon  itself 
with  a  curious  kink.  Like  the  cormorants,  these  birds 
take  life  very  seriously,  and  are  equally  unattractive, 
though  their  quaintness  is  interesting.  They  are  certainly 
most  efficient  water  birds  and  fly  well,  but  are  ungraceful 
and  malodorous — at  any  rate  in  quantity.  They  are, 
however,  of  somewhat  less  dingy  plumage,  and  in  the 
breeding  season  become  almost  brightly  coloured  with 
yellowish  and  brown  tints. 


GEESE  149 

Pelicans  have  only  been  seen  in  the  narrow  channel 
between  Bugalla  Island  and  Bukakata  port  on  the  Buddu 
coast  of  the  west  of  the  lake. 

They  may  also  be  seen  in  Kavirondo  gulf,  which  is  very 
shallow  and  muddy,  but  why  they  do  not  occur  elsewhere 
on  the  sheltered  waters  among  the  islands  it  is  difficult 
to  explain. 

Geese  are,  of  course,  numerous  on  Lake  Victoria,  but 
I  confess  not  so  numerous  as  I  expected  to  find  them, 
and  ducks  were  very  rarely  seen.  I  never  saw  on  Lake 
Victoria  anything  approaching  the  hosts  of  brown  ducks 
seen  in  1916  on  Lake  Bunyonyi  in  the  Kigezi  district  of 
the  south-west  corner  of  Uganda,  or  in  1918  on  Singidda 
Lake  at  the  southern  end  of  the  East  African  rift  valley, 
or  on  the  marshy  land  along  the  central  railway  of  ex- 
German  East  Africa,  near  Dodoma,  in  1917.  The  native 
name  "  Embata  "  applies  to  both  geese  and  ducks.  The 
Egyptian,  or  Zambesi  {Chenalopex  oegyptiacus)  goose,  well 
known  over  so  large  a  part  of  Africa,  and  on  ornamental 
waters  at  home,  is  the  species  most  often  met  with,  and  is 
usually  found  in  little  companies  of  two  or  three,  or  some- 
times half  a  dozen.  It  prefers  especially  an  open  shore  of 
flat  rock  or  sandy  beach — the  white  sand  of  Nsadzi  beach 
was  a  very  favoured  spot,  and  one  could  always  reckon  on 
finding  at  least  a  pair  there. 

They  are  handsome  birds  with  their  mottled  brown  and 
grey  plumage,  and  green  and  white  speculum  on  the  wings, 
and  walk  easily,  carrying  themselves  well  without  waddling. 
As  one  moves  along  the  beach  towards  them  their  agitation 
shows  itself  by  loud  cacklings,  until  they  finally  take  to 
flight  and  make  a  half  circle  over  the  water,  returning  to 
shore  a  little  further  away.  A  wounded  one  that  had 
been  shot  and  was  pursued  by  a  canoe  endeavoured  to 
save  itself  by  diving,  but  I  think  this  bird  only  does  so 
in  its  utmost  extremity. 

A  nest  was  found,  on  July  25,  1914,  at  the  foot  of  a  tree 


150  BIRDS 

behind  a  bank  of  bushes  and  reeds  on  Kimmi  Island  ; 
excavated  in  a  bed  of  dead  diy  leaves  and  beautifully 
lined  with  warm  down,  it  contained  four  white  eggs. 
About  a  week  later,  however,  I  found  only  two  eggs  in 
the  nest,  so  that  possibly  some  had  been  devoured  by 
Varanus  or  a  snake. 

I  have  related  elsewhere  how  a  mongoose  that  ardently 
desired  a  gosling  was  frustrated  by  an  old,  old  trick 
played  upon  it  by  one  of  the  parents. 

The  large  black  and  white  spur-winged  goose  (Plectrop- 
terus  gambensis)  is  not  so  plentiful  as  the  Egyptian  goose, 
but  is  a  much  better  bird  for  the  table.  I  saw  it  so  seldom 
that  I  have  no  notes  about  it. 

Similarly  with  the  brightly  coloured  dainty  little  pigmy 
goose  {Nettopus  auritus),  which  is  found  sparsely  along 
rush  fringed  stretches  of  shore,  such  as  the  north  coast 
of  Bugalla  and  the  channel  between  Damba  and  Kome. 

Rather  curious  little  birds  are  Pratincoles  {Galacto- 
chrysea  emini),  which  may  be  seen  sitting  on  small  rock 
islets.  They  seem  very  sluggish  birds,  and  are  not  very 
interesting  or  attractive.  Short  legged,  with  rather  slender 
bodies  of  grey  colour,  the  rounded  heads  bearing  a  short 
beak,  the  pratincole  is  called  "  Akasalu  "  by  the  natives. 

Of  the  Plovers  and  their  allies  the  most  noticeable  species 
on  the  islands  is  a  stone  curlew  {Oedicnemus  vermiculatus), 
known  to  the  natives  as  "  Mutunwa."  Almost  every 
beach  of  gravel  or  sand  or  flat  rocky  shore  has  a  pair  or 
more  of  these  birds,  which  lay  their  eggs  there,  placing 
the  two  in  a  slight  hollow,  without  any  attempt  at  a  nest. 

If  one  interferes  with  eggs  or  young  they  are  apparently 
removed  by  the  parents.  I  first  noticed  this  on  Damba 
beach,  where  I  found  a  pair  of  eggs  lying  on  the  shingle 
and  examined  them  ;  but  next  day  they  had  disappeared. 
Again,  on  Ngamba,  I  came  across  a  young  bird,  with  the 
other  just  beginning  to  make  its  way  through  the  shell. 
I  helped  it  out,  a  poor  little  bedraggled  feebly  chirping 


NEST   OF    EGYPTIAN    GOOSE    UNDER   TREE. 


1 

^^^^^^^^^^^^^^^^i,^%- .^  *^-»^i           "^^^^^^^^^^^H 

■1 

'  ^> 

^ 

NEST   OF    STON'E   CURLEW    {OEDICNEMUS). 
Two  £ggs  lie  in  front  of  the  stick  lying  obliquely  across  the  left  centre  of  the  picture. 


To  face  p.  150, 


STONE   CURLEW 


151 


object,  and  left  it  there  ;  but  a  few  days  later  both  had 
disappeared.  It  is,  of  course,  possible  that  they  had 
really  been  eaten  by  a  Varanus  lizard  ;  I  have  elsewhere 
described  how  one  seized  a  bird  I  had  shot.  The  Mutunwa 
has  a  most  curious  habit  of,  as  it  were,  shrugging  its 
shoulders,  a  habit  shared  by  many  of  the  kingfishers,  of 
which  the  meaning  is  quite  obscure.  They  are  certainly 
decidedly  procryptic  birds,  and  this  unnecessary  move- 
ment helps  to  reveal  them  when  they  might  otherwise 
escape  notice. 

Their  characteristic  cry  is  often  heard  at  night,  especially 
in  bright  moonlight.  It  begins  with  a  single  high- 
pitched  note,  sharply  accentuated,  and  then  a  series 
beginning  lower  than  the  first,  rising  to  the  same  level 
and  falling  again — a  very  mournful  cadence.  It  may  be 
represented  graphically  thus  : 


d! 


>l      j 


llllfe, 


One  stone  curlew  that  I  shot  on  Nsadzi  in  order  to  in- 
vestigate its  stomach  contents  had  eaten  a  cricket  and 
apparently  a  small  frog,  so  far  as  I  could  tell  from  the 
slender  bones  that  were  aU  that  was  left. 

The  common  Sandpiper  [Tringoides  hypoleucos)  is 
abundant  on  beaches  or  flat  rocks,  very  often  singly, 
sometimes  in  small  flocks. 

It  may  be  seen  at  the  Ripon  falls  paddling  about  in 
the  water  at  the  very  edge  of  the  cascade,  occasionally 
having  to  leap  away  from  an  unusually  large  patter  of 
spray  or  a  rush  of  water.  Possibly  it  feeds  upon  the 
Simulium  larvae  which  adhere  to  the  rocks  in  abundance 
in  such  localities. 


152  BIRDS 

I  once  saw  on  Damba  some  extraordinarily  long  legged 
birds  that  presumably  were  Stilts,  but  they  are  far  from 
common.  The  locality  was  a  very  marshy  piece  of  shore, 
also  frequented  by  snipe. 

On  Kome,  in  1914,  were  seen  some  plovers  which  had 
not  been  met  with  previously,  nor  have  I  seen  them  since, 
although  there  are  large  areas  of  marshy  shore  similar  to 
the  locality  where  they  were  seen. 

The  colouration  was  roughly  as  follows :  Back  grey, 
belly  white,  chest  and  back  of  neck  black,  face  and  front 
of  neck  white.  When  flying  the  bird  shows  black  and  white 
wings.  Subsequently,  in  ex-German  East  Africa,  a  bird 
of  something  the  same  type  was  seen  commonly  on  open 
grassy  plains.  This  was  termed  "  Kibiki "  by  South 
Africans. 

Another  species  of  the  plover  group  was  heard  flying 
overhead  at  night  time  on  Kome.  Its  cry  became  very 
familiar,  and  was  apparently  responsible  for  the  name 
"  Empunya  "  given  to  the  bird  by  the  natives.  Since 
the  meaning  of  this  word  would  be  something  connected 
with  the  word  for  "  to  smell,  or  emit  an  odour,"  it  is 
probably  merely  onomatopoeic,  and  is  quite  descriptive  of 
the  cry. 

Cra7ies  are  represented  in  Uganda  by  one  species  of 
crowned  crane  (Balearica  regulorum),  a  most  orna- 
mental and  graceful  bird  which  would  be  a  splendid 
addition  to  the  peacocks  and  pheasants  often  kept  to 
ornament  a  park.  The  soft  brown  and  grey  and  yellow 
hues,  with  velvety  black  head  furnished  with  scarlet 
wattles  and  erectile  crest,  make  it  a  most  lovely  bird, 
and  its  quaint  antics  when  with  others  of  its  kind  give  it 
additional  interest. 

Unfortunately  they  are  very  seldom  met  with  on  the 
smaller  islands,  and  even  on  Kome  and  Bugalla  are  rare  ; 
and  I  never  saw  a  flock  such  as  may  be  seen  at  Entebbe 
or  Jinja.     Their   cry  has  earned  for  them   the   Luganda 


BUSTARDS— IJLY   TROTTER— IBIS  153 

name  "E'ngali."  The  booming  noise  which  they  make  at 
night,  before  rain,  has  been  already  alluded  to,  and  the 
curious  ignorance  of  the  natives,  who  assign  the  noise  to 
the  puff  adder  ! 

Next  come  the  Bustards,  of  which  a  single  species 
{Otis  melanog aster)  known  as  "  Olunyonkante  "  occurs  on 
islands  where  there  is  a  sufficiently  large  open  grassy 
area.  This  species  shows  black  and  white  wings  when 
flying,  and  has  a  most  ridiculous  little  call  note.  One  hears 
first  a  very  short  low  whistle,  followed  after  a  few  seconds 
by  a  single  sharp  but  very  quiet  note  like  a  bubble 
bursting.  The  peculiar  native  name  would  seem  to  indicate 
that  the  native  considers  it  to  suck  cows,  so  that  this  bird 
holds  a  place  in  folklore  analogous  to  our  "  goat  sucker  " 
in  England. 

Birds  of  the  Rail  family  were  plentiful  among  the  reeds 
and  rushes  of  the  lake  shore.  One,  looking  much  like 
our  English  moorhen,  was  responsible  for  making  a  most 
extraordinary  noise  among  thick  cover — a  sort  of  grunting, 
squealing  and  whining,  quite  indescribable  and  very 
unlike  a  bird  noise.  The  pretty  brown,  yellow  and  black 
Lily  trotter  may  conveniently  be  placed  here,  "  Akatassa  " 
{Actophilus  africanus).  It  is  seen  where  there  are  enough 
water  lily  leaves  or  thick  vegetation  in  the  water  for  it 
to  run  over,  its  very  long  toes  supporting  it  by  distributing 
its  weight  over  a  large  area.  It  is  a  very  quiet  bird,  and 
one  rarely  heard  it  make  any  kind  of  noise  unless  it  was 
angrily  scolding  at  and  driving  away  a  trespasser  on  its 
private  hunting  ground. 

We  next  come  to  the  Ibises,  of  which  I  only  know  two 
species  on  the  islands,  the  most  conspicuous  being  the 
dark  greenish  black  Hagedash  ibis,  known  to  the  natives 
as  "  Empavana,"  the  word  being  an  attempt  to  reproduce 
its  very  characteristic  cry,  which  can  be  indicated  by 
"  Aa-aa-aa,"  This  is  a  very  annoying  bird  if  one  is 
anxious  to  approach   an  animal  without  being  noticed, 


154,  BIRDS 

for  it  is  very  nervous  and  quickly  takes  to  flight  with  noisy 
beating  of  wings  and  raucous  lamenting  cry,  frightening 
everything  within  earshot,  so  that  it  must  be  a  great 
nuisance  to  sportsmen.  I  have  already  related  how  one 
of  them  frustrated  my  hoped  for  interview  with  a  hippo. 
Sometimes  these  birds  perch  on  a  tree  top,  at  other  times 
sit  among  the  rushes  and  bushes  on  the  shore,  but  wher- 
ever they  are  their  wailing  cry  betrays  them.  When 
flushed  they  make  a  great  noise  with  the  hurried  strokes 
of  their  wings  and  have  a  characteristic  flight,  interposing 
an  extra  quick  beat  here  and  there  until  they  feel  steady 
in  the  air.  Presumably  the  main  object  is  to  rise  quickly 
from  the  ground,  and  not  to  place  a  great  horizontal 
distance  between  themselves  and  the  disturber  of  the 
peace. 

The  other  species  is  the  handsome  sacred  ibis  (Ibis 
oethio])ica),  whose  plumage,  half  black,  half  white,  makes 
it  easy  to  recognize.  It  is  very  far  from  common,  and  is 
only  to  be  seen  occasionally  here  and  there,  so  that  it  is 
unfamiliar  to  the  natives,  and  I  could  obtain  no  native 
name  for  it.  During  1914  there  was  usually  to  be  seen 
one  on  a  rock  off  Kizima  Islet,  and  it  was  noted  to  be  a 
very  silent  bird,  thus  contrasting  strangely  with  its 
relative.  I  did  not  notice  the  hurried  flight,  with  inter- 
posed beat,  so  characteristic  of  the  Hagedash  ibis. 

Of  Storks,  several  species  are  noticeable,  particularly  the 
curious  "  open-billed "  species  {Anastomus  lamelligerus), 
the  two  halves  of  whose  beak  do  not  meet  along  the  middle 
of  the  bill,  giving  the  bird  an  unusual  appearance.  It  is 
rather  an  uncouth  and  ungraceful  black  bird,  met  with 
along  the  shore,  where  it  is  said  to  feed  on  the  large 
Ampullaria  "  water  snails,"  its  curious  bill  being  adapted 
to  enable  it  to  deal  with  their  strong  shells.  The  natives 
call  it  "  Enkonamasonko,"  which  shows  that  they  know 
its  habits,  "  E'sonko  "  (jilural  Masonko)  meaning  "  shell," 
and  "  Oku-kona  "  meaning  "  To  knock." 


STORKS  155 

It  is  quite  a  common  bird,  but  only  at  certain  places, 
usually  an  open  rocky  shore  where  the  Ampullariae  are 
easily  found. 

Another  all  black  stork  of  about  the  same  size  {Ciconia 
nigra)  is  often  mistaken  by  the  natives  for  the  "  Mpavana," 
so  that  at  first  when  one  asked  its  name  one  always  got 
the  name  for  the  ibis.  However,  a  more  observant 
native  distinguished  it  as  "  Sombabyuma,"  a  curious 
name  which  implies  that  this  bird  collects  pieces  of 
iron  ! 

Another  stork  of  about  the  same  size,  but  black  and 
white  {Abdimia  abdimii),  appears  from  time  to  time  in 
large  flocks  that,  after  soaring  round  and  round  high  up 
in  the  air,  descend  to  open  grass  land  and  eat  grasshoppers. 

The  natives  call  it  by  the  name  "  Enunda,"  which  is 
apparently  their  equivalent  for  the  English  "  stork," 
for  they  applied  the  same  name  to  a  specimen  of  the  fine 
saddle-billed  stork  {Ephippiorhynchus  senegalensis),  which 
I  once,  and  only  once,  saw  on  the  shore  of  Buvu,  in 
the  Sesse  Archipelago,  in  1912.  It  is  a  fine  bird,  with 
blue-black  and  glossy  bottle-green  and  white  plumage, 
the  huge  bill  being  crimson  and  black  with  a  "  saddle  " 
of  yellow.  The  European  stork,  curiously  enough,  was 
never  met  with  on  the  islands,  and  I  had  never  seen  it 
until  I  found  it  numerous  in  the  Singidda  district  of  ex- 
German  East  Africa,  at  the  southern  end  of  the  great 
East  African  Rift  valley — this  was  in  February  1918. 
The  remarkable  Nilotic  whale  headed  stork  {Balceniceps 
rex)  was  also  absent  from  the  islands,  perhaps  because 
there  was  not  a  large  enough  area  of  papyrus  swamp. 

The  Hammer-head,  or  Tufted  Umbre  {Scopus  umbretta), 
is  not  uncommon  along  the  shore,  although  one  never 
sees  more  than  one  at  a  time,  for  it  appears  to  be  a  solitary 
bird.  It  is  of  a  dull  dark  brown  and  has  a  large  head, 
tufted  as  its  name  implies,  with  a  heavy  bill.  It  is  found 
standing  in  the  shallow  water  of  a  sheltered  pool  or  bay, 


156  BIRDS 

apparently  watching  for  fish  as  do  the  herons,  but  possibly 
also  dozing,  for  I  think  it  is  more  crepuscular  or  nocturnal 
than  diurnal. 

Flamingoes,  somewhat  to  my  surprise,  were  never  met 
with  on  the  Victoria  Nyanja,  but  I  cannot  say  why. 
The  lake  abounds  in  shallow  bays  and  quiet  sheltered 
waters,  where  one  would  think  flamingoes  would  find  all 
they  desire. 

Herons  and  their  aUies  are  numerous  on  the  islands, 
as  might  be  expected.  The  finest  bird  to  be  seen  on  the 
lake  shore  is  the  goliath  heron,  which,  like  many  other 
species  of  the  Uganda  fauna,  extends  its  distribution  to 
the  west  coast. 

This  magnificent  bird  is  known  to  the  natives  as 
"  Kimbala,"  ^  and  may  be  seen  standing  at  the  edge  of  the 
water  or  on  rocks  on  every  island.  I  should  think 
there  may  be  one  to  every  two  miles  of  coast  line.  Such 
large  birds  would,  of  course,  require  extensive  fishing 
grounds,  and  I  have  twice  seen  disputes  between  a  goliath 
heron  and  a  fish  eagle. 

On  the  first  occasion  I  was  examining  the  coast  of 
Buvumira  Isle,  in  1912,  when  one  of  these  great  birds  was 
seen  flying  over  the  surface  of  the  water  with  a  fish  eagle 
in  hot  pursuit.  When  the  eagle  came  uncomfortably  near 
the  heron  dropped  on  to  the  surface  of  the  water  and  sat 
there  with  his  beak  in  a  defensive  position  ready  to  jab 
at  the  eagle  should  it  be  unwise  enough  to  attack,  and 
turning  round  as  so  to  keejD  facing  the  eagle  from  whatever 
direction  it  threatened,  erecting  a  crest  of  feathers  on  top 
of  its  head  when  the  eagle  came  near.  The  eagle  did 
not  venture  to  attack,  and  drew  off  a  little,  whereupon 
the  heron  took  to  flight  again,  its  enormous  wings  beating 
the  air  with  slow  strokes.  Seeing  its  enemy  again  on  the 
wing  the  eagle  made  another  dash  at  it,  whereupon  the 

^  Some  less  observant  natives  call  this  bird  "  Balwa,"  but  I  think  this 
name  belongs  to  another  heron,  possibly  the  Ardea  purpurea. 


GOLIATH  HERON  AND   EAGLE  157 

heron  repeated  its  defensive  tactics,  dropped  on  to  the 
water,  and  took  up  the  same  attitude  as  before. 

As  soon  as  the  eagle  drew  off  the  heron  took  to  wing 
again  and  this  time  was  not  pursued  ;  the  eagle,  being 
satisfied  that  the  trespasser  had  been  driven  from  the  private 
fishing  grounds,  returned  victorious  to  its  favourite  perch, 
while  the  heron  slowly  disappeared  into  the  distance. 

On  the  second  occasion  when  the  two  birds  were  seen 
in  conflict,  the  heron  had  the  best  of  it.  This  was  in 
1913,  when  I  was  going  down  to  see  Nkosi  Islet,  the 
southernmost  of  all  the  Sesse  group.  While  passing  down 
the  channel  between  Kirugu  and  Buguye,  I  saw,  on  the 
islet  Lula,  a  fish  eagle  swoop  down  upon  a  goliath  heron 
that  was  standing  on  the  shore,  but  presumably  trespassing 
on  the  eagle's  preserves. 

There  was  some  rough  and  tumble  business,  and  then  the 
eagle  was  seen  on  the  ground,  and  whenever  it  moved  the 
heron  jabbed  viciously  at  it  with  its  formidable  beak, 
and,  I  think,  had  one  foot  on  the  eagle  to  hold  it  down. 
A  considerable  noise  was  made,  but  I  think  the  heron  was 
chiefly  responsible  for  the  very  savage  snarling  and  grunting 
sounds  that  came  from  the  pair.  I  confess  my  sympathies 
were  with  the  eagle,  who  seemed  to  be  getting  much  the 
worst  of  it,  but  eventually  managed  to  disengage  and 
fly  away,  and  the  heron  did  not  pursue. 

It  would  seem  as  if  the  eagle  was  superior  on  the  wing, 
and  the  heron  knew  it,  but  was  in  the  stronger  position 
on  the  ground.  In  the  case  first  described  the  heron 
was  at  first  seen  on  the  ground,  but  took  to  wing  at  the 
approach  of  the  canoe,  when  the  eagle  gave  chase  ;  presum- 
ably it  had  not  dared  to  attack  before.  The  hoarse, 
raucous  cry  of  the  Kimbala  is  quite  startling  when  one 
suddenly  gets  up,  frightened  by  a  gunshot,  from  a  thick 
bed  of  rushes  where  it  had  been  standing  unperceived. 
It  is  a  handsome  bird,  coloured  with  various  shades  of 
brown  and  purplish  grey.     It  is  curious  that  I  have  never 


158  BIRDS 

seen  one  actually  feeding,  but  presumably  it  catches  fish 
and  frogs  like  other  herons. 

Several  other  species  are  to  be  seen.  A  grey  one  is 
known  as  "  Sekanyolya "  {Ardea  melanocephala),  but  I 
have  nothing  to  say  about  them. 

An  extremely  beautiful  but  seldom  seen  species  was 
noted  in  1918  on  rocks  off  Damba  Island,  a  locality  that 
has  been  alluded  to  before.  There  were  seen,  among  many 
other  birds,  half  a  dozen  great  white  herons  (Herodias 
alba),  collected  on  one  small  low  rock,  their  pure  white 
plumage  and  graceful  build  arousing  intense  admiration. 
Subsequently,  some  were  seen  on  other  islands,  but  they 
are  by  no  means  abundant,  and  the  natives  have  no 
name  for  them  other  than  "  Enyange  nene,"  i.e.  large 
egrets. 

But  the  Egret  {Egretta  garzetta)  is  more  slender,  smaller, 
and  has  a  black  bill  and  legs.  It  is  quite  common  on  the 
islands,  and  may  constantly  be  seen  paddling  at  the  edge 
of  the  water  on  the  beach  or  on  flat  rocks  where  the  waves 
are  breaking,  picking  up  small  fish  from  the  water,  or 
investigating  small  pools  for  frogs,  its  pure  white  plumage 
making  it  very  conspicuous. 

Although  they  usually  fish  by  themselves,  egrets  may 
often  be  seen  at  sunset  in  small  flocks  wending  their  way 
home,  flying  slowly  over  the  surface  of  the  blue  water 
with  hoarse  croaks. 

They  nest  in  much  the  same  situations  as  are  chosen 
by  darters  and  cormorants,  namely,  ambatch  trees  growing 
in  shallow  water.  In  January  1919  I  found  some  young 
almost  ready  to  leave  the  nests. 

A  bird  that  is  often  mistaken  for  the  true  egret  is 
the  white  buff-backed  heron  [Bubulcus  ibis),  which  is 
extremely  abundant  at  Jinja  or  Entebbe,  where  flocks 
may  be  seen  in  attendance  on  cattle,  ready  to  pounce  on 
the  grasshoppers  and  other  prey  disturbed  by  the  move- 
ments of  the  grazing  beasts.     But  they  are  not  so  slenderly 


PIGEONS-  FR  ANCOLINS  159 

built  as  the  more  graceful  egret,  and  their  shorter,  stouter 
bills  are   yellow  instead  of  black,  as  also  are  their  legs. 

Curiously  enough  they  are,  on  the  islands,  no  more 
plentiful  than  the  true  egret,  perhaps  because  there  are 
no  cattle  to  collect  them  together  in  flocks. 

Doves  were  common,  but  several  notable  species  found 
on  the  mainland  were  never  seen  on  the  islands — for 
example,  the  small,  long  tailed  ^na  capensis,  seen  at  Jinja. 
A  forest  species,  whose  long  drawn  out  call  was  heard 
coming  from  the  tops  of  tall  trees  when  I  examined  patches 
of  forest  on  the  Kyagwe  coast,  was  never  heard  in  the 
island  forests.  The  beautiful  green  fruit  pigeon  (Viiiago), 
with  red  bill,  was  quite  common,  as  might  be  expected 
from  the  abundance  of  fig  trees  growing  on  the  rocky 
shores.  It  has  a  long  and  rather  complicated  call,  which 
one  soon  got  to  know,  but  found  impossible  to  imitate. 

Game  Birds  are  chiefly  remarkable  for  their  absence. 
No  guinea  fowls  were  ever  seen  or  heard,  nor  any  of  the 
larger  "  bush-partridge  "  (species  of  Francolin),  It  is 
possible  that  they  had  been  exterminated  by  natives 
trapping  them  in  the  old  days  before  the  outbreak  of 
Sleeping  Sickness. 

A  certain  loud,  ringing  cry  was  so  frequently  heard 
from  the  depths  of  the  forest  belt  on  Bugalla  that  I  soon 
became  thoroughly  familiar  with  it.  But  it  was  long 
before  I  found  out  what  was  the  bird  responsible  for  it. 
One  day  in  the  forest  a  bird  that  at  the  time  was  noted 
to  be  of  the  partridge  type,  ran  out  from  a  clump  of  thick 
undergrowth,  but  seeing  me  almost  at  once  dived  back 
again.  It  was  undoubtedly  the  bird  that  was  responsible 
for  the  well-known  cry  that  had  been  coming  from  that 
spot.  Further  knowledge  of  birds  made  it  obvious  that 
this  must  have  been  one  of  the  forest  Francolins. 

I  believe  that  this  bird  has  much  increased  its  range 
on  the  islands  since  those  days.  Between  December  3rd, 
1918,  and  mid-February  1919,  I  examined  thoroughly  a 


160  BIRDS 

chain  of  islands  which  I  had  visited  in  1914  with  Mr. 
Fiske.  On  the  second  tour  this  forest  Francolin  was 
heard  calling  on  every  isle  that  had  forest  to  shelter  it, 
where  it  was  not  noticed  in   1914. 

The  only  other  game  birds  of  the  islands  are  Quails, 
of  which  two  species  were  met  with  ;  but  save  that  one  is 
much  larger  than  the  other  there  is  nothing  to  be  said 
about  them. 

Birds  of  Prey. — The  most  conspicuous  bird  of  prey  is, 
of  course,  the  glorious  white  breasted  Fish  Eagle  or 
"  Empungu  "  {Haliaetus  vocifer),  which  is  literally  quite  a 
feature  of  the  landscape.  Its  pure  white  head,  neck  and 
breast,  set  off  by  rich  red  brown  and  black  on  body  and 
wings,  render  it  visible  afar  when  perched  on  a  tree 
top  or  prominent  branch  hanging  over  the  water.  Its 
joyous  scream,  uttered  when  soaring  round  and  round 
high  in  the  air,  or  when  perched  on  the  tree,  is  a  most 
delightful  noise,  full  of  life  and  vigour.  When  screaming 
the  bird  throws  back  its  head  until  it  almost  touches  the 
back,  and  the  loud  cry  is  responded  to  by  its  mate,  for 
they  seem  to  live  together  in  couples. 

The  noise  made  by  the  rush  of  air  between  the  pinions 
when  one  of  these  superb  birds  sees  a  fish  at  the  surface 
and  stoops  to  secure  it  can  be  heard  before  one  has  actually 
seen  the  bird,  and  amounts  to  a  loud  roar.  Sometimes 
the  bird  chooses  a  fish  of  such  size  that  it  cannot  lift  it. 
An  officer  of  the  Uganda  Marine  told  me  that  he  had  seen 
one  taken  under  water  by  a  fish  in  which  its  talons  were 
presumably  inextricably  fixed.  It  was  probably  one  of 
the  large  lung  fishes  which  had  come  to  the  surface  for 
a  breath  of  air. 

So  far  as  I  can  remember,  however,  the  eagle  does  not 
usually  plunge  quite  into  the  water,  but  checks  itself 
before  the  impact,  neatly  picking  up  the  wriggling  prey 
with  its  feet,  and  carrying  it  off  to  a  favourite  perch. 

During  brilliantly  fine  weather,  when  there  is  usually 


NEST   OF    OSPREY    (  "  MAKWANZl ") 


To  face  p.  i6o 


FISH  EAGLES  161 

a  steady  southerly  or  south-easterly  breeze,  the  eagles 
soar  round  and  round  high  up  in  the  air  and  scream 
frequently  and  loudly. 

A  native  told  me  that  this  was  a  sign  of  high  wind 
coming,  but  I  do  not  think  it  is  of  any  more  significance 
than  an  indication  of  the  fine  breezy  weather  as  afore- 
said. 

The  nest  of  the  fish  eagle  is  a  conspicuous  structure  in 
the  fork  of  a  large  tree.  In  October  1910  I  saw  a  bird 
carrying  in  its  talons  a  mass  of  building  material  up  to 
the  chosen  nesting  place. 

A  certain  large  "  Muvule  "  tree  at  Jinja  was  in  use  as 
a  nesting  place  in  1914,  and  I  found  it  still  in  use  in 
February  1919,  so  that  these  birds  would  seem  to  choose 
the  same  spot  year  after  year. 

The  fully  fledged  young  bird  has  a  rather  untidy 
appearance,  its  dark  blackish  plumage  being  irregularly 
spotted  with  dull  white,  and  it  only  gradually  acquires 
the  magnificent  snowy  breast  of  its  parents.  The  young, 
two  in  number,  remain  at  the  nest  long  after  they  have 
begun  to  fly,  and  are  apparently  driven  away  by  the 
parents  to  look  after  themselves.  At  least  this  is  the 
interpretation  I  put  on  what  was  seen  on  Kerenge  Island 
in  January  1919.  Two  adult  birds  were  soaring  round  and 
round,  and  a  third,  in  immature  plumage,  was  apparently 
objectionable  to  them,  for  they  kept  swooping  down  and 
obviously  trying  to  drive  it  away,  yet  not  really  en- 
deavouring to  hurt  it,  and  desisting  from  their  attacks 
when  it  went  a  sufficient  distance  away. 

Another  fish  eating  bird  of  prey  is  the  common  Osprey, 
but  I  have  unfortunately  nothing  particular  to  say  about 
it.  The  natives  call  it  "  Makwanzi,"  and  a  nest  photo- 
graphed on  the  small  Islet  of  Wavuziwa  in  January  1919 
was  attributed  to  this  bird. 

After  the  fish  eagle  the  most  conspicuous  bird  of  prey 
on  the  islands  is  a  brown,  yellow  billed  Kite,  "  Akamunyi  " 

12 


162  BIRDS 

{Milvus  oegyptius  parasitus),  which  is  really  extremely 
abundant.  It  was  noticeable  that  the  hiUs  on  certain 
islands,  such  as  Kizima,  always  had  a  number  of  kites 
soaring  over  them,  and  it  seems  probable  that  the  small 
area  of  heated  lands  surrounded  by  cooler  water  caused 
a  continual  up-current  of  air  on  which  it  was  easier  for 
them  to  soar. 

Their  shrill,  quavering  cry  is  very  characteristic  and 
quite  pleasant  to  hear.  I  think  there  are  in  proportion  to 
area  many  more  kites  among  the  islands  than  on  the  main- 
land, at  any  rate  the  cry  is  not  nearly  so  often  heard  at 
Entebbe  or  Jinja.  Possibly  this  is  because  they  are  in  a 
manner  scavengers  of  the  surface  of  the  lake,  and  will 
swoop  down  and  pick  up  small  fish,  or  dead  fish  mangled 
by  gulls,  or  other  objects  floating  on  the  surface.  But 
their  appetites  are  all  embracing.  A  grass  fire  will  attract 
numbers  of  them,  as  well  as  of  other  birds,  who  sail  round 
and  round  ready  to  pounce  on  grasshoppers  and  other 
insects  fleeing  before  the  flames. 

When  winged  termites  swarm  out  of  the  ground  in 
times  of  rain,  kites  speedily  collect  and  circle  round  and 
round,  catching  the  feebly  flying  termites  in  their  feet. 
It  is  pretty  to  see  one  while  on  the  wing  stretch  his  foot 
forward  and  take  the  food  from  it  with  his  beak  in  an 
easy,  leisurely  manner.  The  kite  is  not  above  trying  to 
rob  other  birds  of  their  prey,  and  will  swoop  down  upon 
one  in  the  endeavour  to  make  it  drop  the  fish  which  it 
has  picked  up  for  itself. 

Another  smaller  kite,  known  as  "  Ma'ga "  by  the 
natives  {Elanus  ccendeus),  is  quite  common  on  certain  open 
grassy  islands.  It  is  of  a  soft  dove-grey  and  white.  Its 
habit  of  hovering  vertically  over  one  spot  with  rapidly 
beating  wings  deceived  me  into  thinking  it  was  a  species 
of  kestrel,  but  I  was  put  right  by  Mr.  C.  F.  Belcher.  While 
in  camp  at  Jinja  in  1910  I  used  to  watch  these  birds 
carry  the  mice  which  they  had  caught  on  to  a  certa'-n 


HAWK   AND   CHAMELEON  163 

tree  in  front  of  the  tent,  and  noted  that  they  usually 
pulled  out  the  viscera  and  let  them  drop  to  the  ground 
below. 

A  fairly  large  grey  bird  that  may  have  been  a  buzzard 
was  noted  at  Jinja  under  rather  peculiar  circumstances. 

I  was  walking  along  a  path  thickly  bordered  with 
castor  oil  bushes,  when  I  heard  a  great  fluttering  coming 
from  one,  and  saw  a  large  grey  hawk  hanging  by  its  feet 
from  something  yellowish  on  a  stem  of  the  bush.  It 
appeared  as  if  the  bird  had  caught  its  feet  in  a  tangle  of 
creeper,  and  I  went  up  to  release  it,  wondering  how  I 
was  going  to  avoid  its  sharp  bill. 

When  I  approached  within  a  few  feet  the  hawk  suddenly 
flew  away,  leaving  a  yellow  object  hanging  from  the 
branch.  Only  when  a  bright  red  drop  slowly  trickled 
down  did  I  realize  that  the  object  was  a  chamseleon. 

The  hawk  had  pounced  on  it  and  was  trying  to  drag  it 
from  the  branch,  but  the  chamaeleon  had  such  a  firm  grasp 
with  its  prehensile  tail  that  all  the  flutterings  of  the  bird 
had  not  succeeded  in  dislodging  it.  However,  the  grip 
of  the  talons  had  so  injured  the  chamaeleon  that  it  died 
almost  immediately,  so  that  the  bird  would  have  been 
able  to  carry  it  off  in  the  end. 

I  examined  the  stomach  contents  of  the  chameeleon  and 
found  a  small  snail  and  remains  of  orthopterous  insects, 
probably  tree  dwelling  Locustidae. 

A  propos  this  observation,  it  may  be  said  that  the  small 
brown  lizards  that  run  about  on  the  grass  roofs  of  native 
huts  appear  to  be  a  desirable  food,  for  one  often  sees 
birds  of  prey  swooping  down  on  them. 

I  once  saw  a  large  cock  peck  at  one  till  it  was  disabled 
and  then  swallow  it  whole,  a  disgusting  sight  ! 

Owls. — The  cries  of  two  species  of  owl  are  very  familiar. 
One  is  a  melodious  quaver,  heard  on  moonlit  nights, 
the  other  a  deep  soft  "  Hoo-hoo,"  probably  uttered  by  a 
big  "long  eared"  owl   {Bubo  lacteus).     During  the  day 


164  BIRDS      ^ 

time  one  often  hears  quite  a  different  noise  proceeding 
from  a  thick  shady  tree,  obviously  emanating  from  an 
owl,  bub  whether  from  the  latter  sj)ecies  or  another  I 
cannot  say. 

As  with  other  groups  of  birds,  notable  absentees  from  the 
islands  may  be  mentioned  among  birds  of  prey.  Vultures 
were  never  seen,  but  this  is  perhaps  what  might  be  expected 
from  the  absence  of  game.  The  beautiful  Bateleur  eagle 
{Helotarsus  ecaudatus),  so  noticeable  on  the  mainland,  was 
either  absent  or  so  scarce  on  the  islands  that  I  cannot 
remember  having  seen  it  there. 

Another  fine  species,  the  Black  and  White  Crested 
Eagle  {Spizaetus  coronatus),  known  to  the  Baganda  as 
"  Wonzi,"  was  only  very  occasionally  seen.  I  first  became 
acquainted  with  this  handsome,  fierce  looking  bird  at 
Jinja,  where  its  rather  weird  scream  was  often  heard, 
and  the  bird  was  often  seen  to  perch  on  the  summit 
of  a  dead  tree. 

The  next  family  to  be  mentioned  is  that  of  the  Parrots, 
about  which  I  have  not  much  to  say,  since  I  have  only 
met  with  one  species  on  the  islands.  This  is  curious, 
because  at  Entebbe  and  Bukakata  and  Jinja  may  be  seen 
quite  commonly  one  of  the  small  green  parrots  with  yellow 
shoulders. 

The  well  known  grey  parrot  with  red  tail  occurs  on 
many  of  the  larger  forested  islands,  and  its  discordant 
shrieks  were  familiar.  At  daybreak  and  eventide  they 
fly  to  and  from  their  favourite  feeding  grounds  in  small 
flocks,  and,  like  no  other  bird,  chatter  and  whistle  con- 
tinually as  they  go.  Often  one  hears  the  well  known 
noises  high  overhead  before  the  birds  have  come  into 
view. 

On  Sanga  Islet  one  day,  there  were  some  parrots 
feeding  in  the  trees  which  took  alarm  and  flew  off  as 
I  walked  underneatli.  One  of  them  gave  a  call  which 
seemed  to  be  an  imitation  of  the   monkey's  alarm,   the 


PLAINTAIN   EATERS  165 

only  example  I  can  cite  of  a  wild  parrot  copying  other 
sounds. 

After  the  parrots  come  the  Plaintain  Eaters  {Muso- 
phagidae),  one  of  which  {Musophaga  rossae),  known  to  the 
natives  as  "  Fulungu,"  is  one  of  the  loveliest  birds  of 
Uganda. 

Somewhere  about  the  size  of  a  rook,  but  with  much 
larger  tail,  this  bird  has  deep  purplish  blue  plumage 
with  bright  crimson  patches  on  the  wings,  making  it 
very  conspicuous  when  it  flies.  It  also  makes  itself 
conspicuous  by  its  voice,  for  it  is  a  noisy  bird.  A  company 
of  them  will  be  heard  apparently  working  themselves  up 
to  concert  pitch,  with  short  cacklings  and  gurglings, 
and  then  they  suddenly  all  burst  out  together  into  loud, 
not  unmusical  cooing  in  a  most  pleasing  manner. 

These  birds  are  typically  forest  species,  and  are  only 
seen  where  the  forests  are  of  some  size,  so  they  do  not 
occur  .on  the  smaller  islets. 

Another  species  of  very  different  appearance  has  much 
less  gaudy  plumage,  being  ashy  grey,  and  showing  patches 
of  black  and  white  on  wings  and  tail  when  flying  :  probably 
it  is  Schizorhis.  I  often  used  to  see  a  pair  on  Damba, 
where  a  marshy  piece  of  shore  had  ambatch  trees  in  flower 
that  were  highly  attractive  to  these  birds,  w^hich  were 
frequently  seen  pulling  off  the  bright  yellow  flowers  and 
devouring  them. 

They,  like  the  Musophaga,  are  noisy  birds,  and  attract 
attention  by  their  vociferous  habits. 

One,  presumably  the  cock  bird,  used  to  do  what  airmen 
call ."  stunts  "  in  the  air,  shooting  vertically  upwards  and 
then  dropping  headforemost  to  join  the  other  in  the 
ambatch  bush,  with  the  accompaniment  of  loud  cackling 
and  croAving  noises.  Though  so  frequently  seen  in  the 
ambatch  bushes  they  always  came  from  the  forest,  to 
which  they  retired  when  alarmed. 

The  Lark-heeled  Cuckoos  or  Coucals  (Centropidae)  abound 


166  BIRDS 

among  the  forests  and  patches  of  bush  on  the  islands,  but 
there  are  differences  from  the  mainland  in  the  propor- 
tions of  the  species.  Their  liquid  gurgling  notes,  descend- 
ing and  ascending  again,  have  earned  for  them  the  native 
name  "  E'tutuma  "  and  the  English  "  Bottle  Bird,"  the 
latter  name  because  of  the  resemblance  to  the  noise 
made  by  water  being  poured  *out  of  a  bottle  with  long 
narrow  neck. 

Generally  speaking,  they  are  skulking  birds,  avoiding 
the  open  and  concealing  themselves  among  bushes,  under- 
growth or  papyrus,  whence  they  fly  heavily  away  with 
broad  tail  outspread. 

Heavily  built,  with  large  stout  beaks,  they  cannot  be 
considered  attractive,  though  their  rich  brown,  black 
and  white  or  yellowish  plumage  is  often  beautiful. 

A  species  that  was  unusually  abundant  on  Bugalla 
(Ceuthmochares  ceneus)  was  of  a  dark  greenish  black  all 
over,  with  the  large  bill  bright  yellow.  Its  note  also  was 
somewhat  different  from  that  of  most  coucals,  being  a 
harsh  screech.  I  saw  one  fly  away  from  a  clump  of  bush 
with  a  butterfly  held  in  its  beak,  but  another  that  I  shot 
had  fed  largely  on  hairy  caterj^illars,  as  is  the  cuckoo 
custom.  So  much  less  common  is  this  species  elsewhere 
that  I  cannot  remember  having  noticed  it  on  other  islands 
or  the  mainland.  On  the  other  hand,  a  certain  large 
species,  whose  deep  booming  call  is  heard  in  mainland 
forests,  was  absent  from  the  islands. 

Next  to  be  mentioned  are  the  Cuckoos.  I  am  familiar 
with  the  notes  of  only  two  species  of  cuckoo  on  the  islands, 
one  of  which  {Cuculus  solitarius)  is  very  common  and  from 
its  cry  has  been  named  "  Sekoko  "  by  the  natives.  The 
frequently  reiterated  call  is  a  descending  sequence  of 
three  notes,  and  during  the  rainy  season  is  very  noticeable, 
the  bird  sitting  perched  in  a  conspicuous  place  and  calling 
again  and  again  as  does  our  English  species. 

Though  its  colouring  is  different  from  that  of  the  latter 


VIEW    FROM    CAMP    ON    KOME,    LOOKING    EASTWARDS. 
Damba  Isle  in  far  distance. 


VIEW   TOWARDS    BUVUMIRA    FROM    BUGALLA    CAMP. 


To  face  p.  iC6. 


CUCKOOS— BARBETS  167 

bird,  the  Sekoko  is  very  obviously  a  cuckoo,  both  when 
seen  perching  and  on  the  wing.  It  seems  to  call  only 
during  the  two  periods  of  greatest  rainfuU,  when  it  is 
presumably  breeding. 

The  other  cuckoo  whose  note  is  familiar  is  the 
"  Ekirimululu,"  (Chrysococcyx  caprius  or  C.  klaasi),  one 
of  the  bronze  cuckoos,  a  small  species,  metallic  green 
above  and  whitish  beneath.  The  native  name,  like  so 
many  others,  is  doubtless  onomatopoeic. 

Another  group,  the  Barbels,  is  strangely  unfamiliar  on 
the  islands.  One  of  the  commonest  of  all,  the  little  Copper- 
smith {Barbatula  leucolaima),  has  never  been  heard  on 
any  island,  although  its  monotonous  "  Tonk-tonk-tonk  " 
can  be  heard  all  day  long  in  the  Entebbe  gardens.  Their 
absence  from  the  islands  was  made  more  noticeable  when 
in  January  1919  I  went  across  to  the  Kyagwe  coast  from 
the  camps  on  Kerenge  and  Wema.  Almost  immediately 
one  landed  on  the  mainland  one  heard  the  well  known 
metallic  note  in  the  forest,  together  with  the  notes  of 
other  birds  not  present  on  the  islands. 

Larger,  red  breasted  barbets  have  not  been  noticed 
either  there,  but  they  do  not  force  themselves  upon  one's 
attention  as  does  the  persistent  coppersmith. 

The  next  family,  Coliidae,  is  easily  dealt  with,  for  they 
are  absent  from  islands  that  have  been  visited,  and  since 
I  was  quite  familiar  with  them  at  Jinja  before  I  first  went 
on  to  the  islands,  they  would  certainly  have  been  seen  or 
heard,  for  I  know  the  twittering  sound  they  make  very 
well ;  it  is  constantly  heard  in  the  gardens  at  Entebbe. 

We  now  come  to  the  Rollers  and  their  allies.  Rollers 
themselves  may  be  dismissed  in  a  few  words,  for  I  never 
saw  one  on  the  islands.  I  had  seen  them  at  Jinja  in  1910, 
and  thus  knew  their  appearance,  and,  having  seen  them 
in  numbers  during  the  East  African  campaign,  was  on  the 
look  out  for  them  when  I  returned  to  the  islands  in  Decem- 
ber 1918,  but  the  result  was  the  same. 


168  BIRDS 

This  seems  very  curious,  and  I  should  like  a  practised 
ornithologist  to  confirm  or  contradict  the  statement. 

Other  members  of  the  sub -order  now  being  considered 
are  the  Hornbills,  one  of  which  {Bycanistes  subcylindricus) 
is  one  of  the  most  characteristic  birds  of  the  Uganda 
forests,  and  abounds  on  the  islands.  This  great  black 
and  white  bird  with  its  curious  bill  is  known  to  the  natives 
as  "  E'nga-nga,"  from  its  nasal,  raucous  cry.  It  is  a  noisy 
and  conspicuous  creature,  clumsy  and  grotesque  in  its 
habits,  and  is  perceived  both  by  ear  and  eye  from  a 
considerable  distance  away.  The  flight  is  heavy,  and  the 
beating  of  the  wings  for  a  few  strokes  is  followed  by  a 
pause  during  which  the  bird  sails  through  the  air  with 
wings  outspread,  making  a  loud  roaring  noise  presumably 
owing  to  the  arrangement  of  the  feathers.  When  an 
"  E'nga-nga  "  flies  past,  I  am  always  reminded  of  the  noise 
made  by  a  puffing  locomotive  as  one  hears  it  coming 
from  a  distance,  the  noise  rising  in  pitch  and  getting  louder 
as  the  engine  approaches,  falling  and  dying  away  as  it 
disappears  in  the  distance.  The  bird  also  frequently 
screams  while  flying,  as  if  to  let  all  the  world  know  where 
it  is. 

I  believe  that  there  is  an  explanation  of  this  noisy 
flight  as  aposematic — the  conspicuous  bird  makes  itself 
perceived  by  ear  as  well  as  eye  in  order  that  enemies  may 
recognize  it.  It  is  of  interest  that  Dr.  G.  A.  K.  Marshall 
records  that  the  flesh  of  an  allied  species  was  found  dis- 
tasteful by  a  mongoose,  and  that  natives  look  on  it  as  so 
poisonous  that  it  will  render  water  unfit  for  drinking  if 
the  carcase  falls  into  a  stream. ^  The  subject  of  aposematic 
flight  will  be  brought  up  again  in  the  chapter  on 
the  Hymenoptera  in  connection  with  the  fossorial  Pom- 
pilidae. 

Foolish  looking  as  is  the  "  E'nga-nga,"  it  is  surpassed 
in  that  respect  by  a  more  slenderly  built  smaller  species, 

1  Proc.  Ent.  Soc.  Lorid.,   1902,  pp.    378-9. 


KINGFISHERS  169 

without  any  casque  on  the  bill,  whose  appearance  always 
fills  me  with  resentment  that  it  should  exist  at  all 
{Lophoceros  melanoleucus).  It  has  a  floppy  flight,  rising 
and  falling  as  it  flaps  its  way  along  with  inane,  shrill 
cries.  Its  dull  whitish  and  black  plumage  has  not  the  pure 
tints  and  arresting  appearance  of  the  "  E'nga-nga,"  and 
indeed  I  find  it  difiicult  to  say  anything  nice  about  this 
bird. 

No  other  hornbills  than  these  two  species  have  been 
noticed  on  the  islands. 

Next  to  be  mentioned  are  Kingfishers,  and  it  is  curious 
that  the  natives  have  the  same  name  for  one  very  common 
black  and  grey  spotted  species  as  for  Bee-eaters  ("  Mujolo  "), 
but  other  kingfishers  are  known  as  "  Akasimagizi." 

The  "  Mujolo  "  kingfisher  (Ceryle  rudis)  is  extremely 
common  along  the  lake  shore,  where  shallow  water  with 
sandy  bottom  provides  good  fishing  grounds.  Its  habits 
are  somewhat  different  from  those  of  other  species,  such 
as  our  familiar  one  at  home,  which  plunges  into  the  water 
from  some  commanding  perch.  Ceryle  rudis  hovers  over 
the  water,  head  hanging  down  with  beak  pointing  vertically 
to  the  surface,  wings  rapidly  beating  like  those  of  a  kestrel. 
Often  it  has  to  wait  a  long  time,  and  change  its  position 
till  some  unwary  little  fish  comes  near  enough  to  the 
surface,  when  the  kingfisher  plunges  in  head  foremost  and 
secures  it.  This  bird  is  rather  vociferous,  and  its  twittering 
cry  is  very  often  heard  as  it  flies  across  the  water,  keeping 
close  to  the  surface.  Another  species  of  Ceryle  {C.  maxima) 
is  scarce,  and  of  solitary  habits,  very  much  larger  than 
any  other  kingfisher  on  the  islands.  It  lurks  among 
bushes  overhanging  the  water,  and  is  usually  first  noticed 
flying  away  when  it  has  been  disturbed,  uttering  a  loud 
unmusical  bleating  cry. 

Beautiful  little  species  of  the  genus  Ispidina  (?  picta) 
are  often  seen  among  the  rushes  growing  in  shallow  water 
or  on  low  t^vigs  of  ambatch  trees  just  above  the  water, 


170  BIRDS 

whence  they  plunge  in  to  secure  their  prey.  Their  feeble 
little  piping  note  is  much  like  that  of  our  English  king- 
fisher, but  though  very  soft  it  often  directs  one's  attention 
to  these  lovely  little  birds  as  they  dart  past. 

About  the  size  of  a  sparrow,  but,  of  course,  of  different 
appearance,  with  short  tail  and  enormous  bright  red 
beak,  these  birds  have  lovely  orange  and  deep  blue 
plumage. 

Natives  say  that  if  one  comes  near  their  house  it  is  an 
omen  that  some  one  is  going  to  die  j  and  it  was  a  curious 
coincidence  on  Bugalla  that  when  one  of  my  canoe-men 
was  ill  vrith.  pneumonia  one  of  these  birds  was  frequently 
noticed  in  the  camp,  although  I  had  not  seen  it  there 
before. 

I  did  not  know  the  superstition  until  some  time  after 
this.  Fortunately  the  canoe-man  recovered  ;  perhaps  if 
he  had  known  the  bird  of  evil  omen  was  there  the  issue 
would  have  been  less  satisfactory  ! 

Another  kingfisher,  of  different  habits,  is  Halcyon 
senegahnsis,  whose  large  beak  and  legs  of  crimson  contrast 
beautifully  -^-ith  its  sky  blue  wings  and  back  and  grey 
under  surface.  This  is  a  forest  or  bush  frequenting  species 
which  has  given  up  a  fish  diet  in  favour  of  large  grass- 
hoppers. 

Sitting  on  a  branch  it  watches  the  grass  for  movements 
and  then  pounces  down  on  a  "  Janzi  "  grasshopper  which 
it  carries  back  to  the  perch.  Here  the  unfortunate  bulky 
insect  is  banged  against  the  branch  until  it  is  in  the  right 
condition  to  be  swallowed  whole.  This  kingfisher  has  a 
loud  and  cheerful  cry.  It  commences  with  a  sharp  high- 
pitched  note  which  is  followed  by  a  churring  descent  down 
the  scale,  and  on  a  bright  sunny  morning  this  familiar 
sound  may  be  heard  over  and  over  again. 

I  saw  an  interesting  little  incident  on  Kerenge  in  1914. 
One  of  these  birds  was  angrily  scolding  on  a  perch  which  he 
considered  to  be  his,   but  the  justice  of  the  claim  was 


KINGFISHERS— BEE-EATERS  171 

disputed  by  one  of  the  Paradise  flycatchers,  which  kept 
trying  to  get  at  the  kingfisher  from  behind.  The  other, 
however,  spun  round  on  the  perch  just  as  quickly  so  as 
always  to  face  the  angry  flycatcher. 

But  at  length  another  flycatcher  came  up,  and  the 
kingfisher  made  off,  thinking  discretion  the  better  part  of 
valour. 

Another  species  of  Halcyon  may  here  be  mentioned  on 
account  of  its  remarkable  absence  from  the  islands.  This 
duU  mottled  greyish  bird,  H.  chelicuti,  is  abundant  both 
at  Jinja  and  Entebbe,  where  its  "  cheer-oh  "  cry  may  often 
be  heard  in  chorus,  and  yet  I  never  heard  it  on  the  islands, 
although  Van  Someren  gives  "  Sesse  Isles  "  as  a  locality 
for  this  species  in  his  check  list.^ 

The  absence  of  the  insectivorous  Rollers  seems  to  be 
compensated  on  the  islands  by  great  abundance  of  their 
allies  the  Bee-eaters.  These  graceful  birds,  known  to  the 
natives  as  "  Mujolo,"  soon  attract  attention  from  their 
habit  of  perching  on  the  tip  of  a  dead  bough  in  a  com- 
manding position  and  swooping  down  on  their  prey, 
returning  with  it  to  the  same  perch.  Two  species,  Merops 
superciliosus  and  Melittophagus  meridionalis,  became  very 
well  known,  and  the  liquid  twitter  of  the  former  was  one 
of  the  most  familiar  bird  sounds. 

When  a  blustery  wind  is  bringing  up  storm  clouds,  this 
bird  often  soars  overhead  innumbers,  braving  the  buffeting 
of  the  gusts  of  wind  and  possibly  catching  the  insects  that 
are  driven  before  the  storm. 

Melittophagus  is  found  more  often  in  grassy  places,  or 
at  the  edge  of  the  forest  perched  on  an  especially  tall 
stem  of  grass  or  rush.  It  keeps  nearer  to  the  ground  than 
does  its  larger,  long-tailed  relative.  Neither  of  these  birds 
is  brilliantly  coloured,  but  their  green,  yellowish,  and 
brown  hues  are  very  pleasing,  and  their  long  bills  and 
graceful  shapes  give  them  a  very  attractive  appearance. 

1  The  Ibis,  1916,  p.  244. 


172  BIRDS 

I  noticed  particularly  that  Dragon-flies  are  a  very  favourite 
food  of  both  species,  as  well  as  the  bees  and  other 
Hymenoptera  on  which  they  are  well  known  to  feed, 
which  were  constantly  found  in  the  stomachs  when  I 
was  searching  for  evidence  that  the  Tse-tse  fly  was  eaten 
by  birds.  (See  vol.  xiv  of  Sleeping  Sickness  Reports  of 
the  Royal  Society,   1913,  pp.   15-16.) 

Stomach  Contents  of  Bee-eatees. 
Merops  superciliosus.  Mclittophagus  meridionalis. 

1.  Mainly  dragon  flies.  1.  Mainly  dragon  flies. 

2.  Dragon  flies  and  honey  bees.  2.  Dragon  flies  and  honey  bees. 

3.  Dragon  flies  and  honey  bees.  3.  Dragon  flies. 

4.  Dragon  flies  and  honey  bees.  4.  Dragon  flies. 

5.  Dragon  flies  and  honey  bees.  5.  Dragon    flies    and    small   beetle 

(Lamellicorn). 

6.  Dragon  flies  and  honey  bees.  6.  Winged    ants    and    one    small 

dragon  fly. 

7.  Dragon  flies  and  honey  bees.  7.  Dragon  flies  and  bees. 

8.  Dragon  flies  and  honej^  bees.  *8.  Winged  ants  only. 

9.  Dragon  flies  and  honey  bees.  *9.  Winged  ants' and  one  Agrionid 

dragon  fly. 

10.  Dragon  flies  and  honey  bees.        *]0.  Winged  ants  and  a  small  species 

of  Chrysididae. 

11.  Dragon  flies  and  honey  bees.        *11.  Winged  ants. 

12.  Dragon    flies,    bees,    and    a 

Beloyiogaster  wasp. 

27.  Dragon  flies.  *  These  were  all  shot  on  the  same 

28.  Dragon  flies.  day  (11-12-11). 

29.  Dragon  flies  and  bees. 

30.  Dragon  flies  and  bees. 

31.  Dragon  flies  and  bees. 

32.  Dragon  flies. 

33.  Dragon  flies  and  bees. 

34.  Caterpillars  and  young  Mantidae. 

35.  Eleven  bees. 

36.  Twelve  bees,  one  wasp,  one 

dragon  fly. 

37.  Twelve   bees,    one   male    Stink 

ant  (Paltothyreus). 

Frequently  one  would  hear  a  loud  tapping  noise,  and 
looking  up  would  see  a  bee-eater  with  a  large  dragon  fly 
in  its  beak  banging  it  against  the  perch  on  which  it  sat, 
finding  the  long  body  and  wings  rather  unmanageable, 
for  they  swallow  the  dragon  flies  wings  and  all. 


NIGHTJARS  173 

Butterflies  appear  to  be  eaten  by  Melittophagus,  for 
I  have  found  on  the  ground,  under  a  grass  stem  on  which 
one  had  been  sitting,  wings  of  the  Httle  yellow  Terias 
butterflies,  although  I  have  not  actually  witnessed  the 
capture  in  this  case. 

Another  group  of  birds  allied  to  the  Rollers  may  be 
dismissed  in  a  few  words,  namely,  the  Wood  hoopoes 
{Irrisorinae),  for  I  have  never  met  with  them  on  the 
islands,  and  first  saw  them  when  on  active  service  in 
German  East  Africa. 

Such  noisy  and  conspicuous  birds  could  hardly  have 
escaped  notice  had  they  been  on  the  islands,  and  when  I 
returned  in  1918  they  were  watched  for,  but  never  seen. 

The  family  of  Goatsuckers,  or  Nightjars,  is  represented 
on  the  islands  by  a  species  of  Caprimulgus,  whose  native 
name  is  "  Olubugabuga,"  presumably  an  attempt  to 
reproduce  one  of  the  noises  that  it  makes.  On  moonlit 
nights,  when  owls  are  also  heard,  these  birds  keep  up  a 
continual  "  Tok-tok-tok-tok-tok,"  varied  occasionally  by 
the  melodious  cry  from  which  their  name  is  derived. 

The  bird  itself  is  often  flushed  during  tday  time  from  its 
resting  place  in  places  that  may  sometimes  be  quite  open 
and  fully  exposed  to  the  hot  sun,  or  sometimes  shaded  and 
among  bracken.  There  is  nothing  about  the  bird  to  call 
for  remark,  unlike  the  East  African  species  with  long 
floating  plumes,  which  has  not  been  met  with  on  the 
islands. 

It  is,  of  course,  highly  probable  that  there  is  more  than 
one  nightjar  on  the  islands,  but  I  am  familiar  with  only 
one  cry. 

We  now  come  to  the  great  order  of  Passeriformes, 
embracing  large  numbers  of  small  birds,  which  I  must 
perforce  pass  over  in  silence,  not  being  sufficiently  familiar 
with  the  comparatively  inconspicuous  species. 

Certain  species,  however,  call  for  notice,  and  first 
among  them  are  the  Flycatchers  (Muscicapidae),  of  which 


174  BIRDS 

two  species  particularly  attract  attention.  The  first, 
Tchitrea  emini,  is  illustrated  from  a  photograph  which 
shows  well  a  very  beautiful  feature,  namely,  the  long 
snow  white  tail  plumes  assumed  by  the  cock  bird  in 
the  breeding  seasons.  The  rich  chestnut  brown,  black 
and  white  plumage  of  body  and  wings  is  set  off  by 
slaty  blue  black  crested  head,  and  it  is  a  delight  to 
watch  the  vivacious  bird,  as  it  is  for  ever  flitting  among 
the  branches  and  chasing  another  from  perch  to  perch. 
The  insistent  call,  quite  impossible  to  describe,  loud  and 
ringing,  was  the  first  bird  note  to  be  heard  in  the  early 
morning  from  the  forest  around  the  camp  on  Bugalla. 
As  soon  as  the  darkness  began  to  lighten  these  delightful 
birds  were  awake  and  filled  the  forest  with  their  call. 
The  native  name  for  this  bird  is  "  Kunguvu."  When  I 
left  Bugalla  I  went  home,  but  the  memory  of  the  call 
there  has  persisted  clearly,  and  I  am  sure  that  the  Bugalla 
race  of  the  Kunguvu  has  its  own  call,  i.e.  a  geographical 
race  is  being  developed.  The  bird  is  plentiful  enough  on 
many  other  islands  ;  indeed,  it  is  one  of  the  species  which 
is  far  more  abundant  on  islands  than  on  the  mainland, 
but  nowhere  has  its  call  quite  the  same  character  and 
finish  as  on  Bugalla.  I  particularly  noticed  this  during 
the  tours  of  1914  and  1918-19,  during  the  letter  of  which 
several  forests  on  the  mainland  coast  were  visited. 

It  is  not  surprising  that  the  birds  on  a  large  island  such 
as  Bugalla  should  be  forming  a  local  race — they  are 
confined  to  the  forest  and  do  not  take  long  fiights. 

One  was  never  tired  of  seeing  the  cock  bird  pursuing 
the  hen  among  the  branches,  excitedly  calling  to  her, 
with  snow  white  plumes  trailing  in  the  air  as  he  flitted 
from  branch  to  branch.  The  nest  is  a  small  shallow  cup- 
shaped  structure  ;  I  have  seen  it  fastened  to  the  end  of  a 
dependent  creeper,  quite  exposed  in  the  open,  but  in  such 
a  position  that  nothing  without  wings  could  reach  it. 
The  hen  bird  was  fully  exposed  as  she  sat. 


KUNGUVU  "    FLY-CATCHER    {tCHITREA    EMINl) 
Foot-rule  on  right. 


.NEST    OK    CROCODILE. 
The  marks  of  the  mother's  body  and  tail  on  the  sand  can  be  plainly  seen. 

To  face  p.  174V 


FLYCATCHERS— SHRIKES  175 

Another  delightful  little  bird  that  soon  became  very- 
familiar  on  Bugalla  was  the  black  and  white  flycatcher, 
with  bright  red  wattle  over  the  eye,  probably  Platysteira 
jacksoni,  whose  call  note  is  very  characteristic.  Two 
birds  were  often  heard  calling  one  to  another.  The  first, 
with  high-pitched  pipe,  would  sing  "  How  are  you  ?  "  to 
which  the   other  responded,  "  I'm  pret-ty  well,  thanks." 

By  whistling  the  first  phrase  I  could  often  get  the 
answer  and  bring  the  bird  near.  Like  Tchitrea  this  bird 
seems  to  be  forming  a  local  race  on  Bugalla,  for  the  call 
elsewhere  is  not  exactly  the  same,  although  one  can  recog- 
nize it  as  coming  from  the  same  bird. 

It  is  not  so  much  a  forest  frequenter  as  Tchitrea, 
being  found  more  among  the  clumps  of  bush  and  copses 
that  make  the  park  like  country  on  the  larger  islands. 

A  third  very  pretty  little  flycatcher  {Elminia  longicauda) 
is  worth  noticing  here,  because  I  have  not  seen  it  on  the 
islands,  save  once  on  Kizima,  though  it  is  often  seen  in 
the  gardens  of  Entebbe.  It  is  a  light  blue  bird  which  has 
a  habit  of  spreading  out  its  tail  fan  wise,  and  hence  attracts 
one's  attention. 

Shrikes  are  noteworthy  because  several  species  familiar 
in  the  gardens  of  Entebbe  and  Jinja  have  never  been 
seen  on  the  islands.  Conspicuous  among  these  is  the 
beautiful  black  bird  with  scarlet  breast  {Laniarius 
erythrogaster),  pairs  of  which  haunt  Hibiscus  bushes,  whose 
red  flowers  exactly  correspond  with  the  breast  of  the  bird. 

They  have  a  call  note  which  may  be  crudely  represented 
by  "  What-ho. "  This  is  uttered  by  one,  and  simultaneously 
the  other  of  the  pair  makes  a  harsh  scolding  or  churring 
noise,  not  at  all  musical.  It  is  curious  that  many  shrikes 
have  this  habit  of  uttering  a  joint  call  ;  for  instance,  the 
long  tailed  black  and  white  species,  whose  very  musical 
notes  I  have  often  heard  on  mainland  but  never  on  an 
island. 

A  brown  shrike  (?  Pomatorrhynchus)  that  was  shot  on 


176  BIRDS 

Damba  Isle  was  found  to  have  eaten  only  grasshoppers 
in  two  cases,  in  the  third  grasshoppers  and  one  beetle. 

Very  noticeable  absentees  from  the  islands  are  the  black, 
fork-tailed,  insectivorous  Drongos  (Dicruridae) ,  which  were 
never  met  with  there.  The  first  ones  I  ever  saw  were  on 
the  frontier  between  German  East  Africa  and  Uganda 
in  the  early  days  of  the  war,  and  later  in  various  parts  of 
German  East  Africa  they  were  seen  abundantly,  so  that 
I  became  thoroughly  familiar  with  them.  When  I  returned 
to  the  islands  in  1918  for  about  three  months,  I  should 
therefore  certainly  have  seen  Drongos  had  they  been 
present.  It  has  seemed  to  me  during  my  wanderings 
that  where  Drongos  were  abundant  Bee-eaters  were  scarce, 
and  since  Bee-eaters  appear  to  be  unusually  plentiful  on 
the  islands  and  Drongos  are  absent,  it  is  possible  that  these 
birds  of  similar  habits  take  each  other's  place  to  a  certain 
extent. 

The  Starling  family  is  also  notable  for  the  absence  of 
conspicuous  species  from  the  islands,  viz.  the  Glossy 
Starlings,  which  certainly  could  not  escape  notice.  These 
birds  have  the  typical  shape  and  noisy  habits  of  our 
home  species,  but  their  dark  plumage  is  resplendent  with 
metallic  purple  and  green.  Their  harsh  voices  are  very 
familiar  at  Entebbe  among  the  tall  trees,  and  their  noisy 
flight  also  renders  them  conspicuous  to  the  ear.  Directly 
I  entered  the  forests  on  the  Kyagwe  coast  opposite  the 
islands  where  I  was  working,  these  noisy  birds  attracted 
attention,  so  that  I  am  quite  sure  they  do  not  exist  on  any 
island  I  have  visited. 

Weaver  Birds  ("  Endegeya  ")  are  abundant  among  the 
ambatches  which  overhang  the  water  ;  but  some  species, 
that  make  their  nests  in  colonies  on  large  trees  on  the 
mainland,  so  that  the  noise  of  them  at  a  little  distance  is 
like  the  sound  of  a  waterfall,  have  not  been  met  with 
on  the  islands. 

Neither  have  I  seen  the  Bishop  and  Widow  finches, 


FINCHES—SUNBIRDS  177 

beautiful  brightly  coloured  birds,  which  could  hardly 
escape  notice. 

The  Fringillidae,  or  Finches,  would  doubtless  be  of  much 
interest  to  an  ornithologist,  but  I  have  little  knowledge, 
and  less  to  say,  about  them.  Noteworthy  varieties  on  the 
islands  are  Sparrows,  "  Enkazalugya  "  {Passer  griseus),  of 
which  very  few  were  ever  seen  ;  possibly  the  absence  of 
mankind  has  something  to  do  with  this.  Another  notable 
absentee  is  a  curious  rotund  little  grass  finch,  which  is 
abundant  at  Jinja  and  Entebbe.  The  cock  bird  when 
adult  is  black  and  white,  and  has  very  long  floating  tail 
feathers  which  appear  to  hinder  his  flight.  He  flits  for  a 
short  distance  over  the  grass  with  an  up  and  down  motion, 
uttering  feeble  chirps,  accompanied  by  a  flock  of  brown, 
insigniflcant  looking  individuals,  which  I  always  took  for 
females.  Mr.  C.  F.  Belcher,  however,  tells  me  that  most 
of  them  are  immature  males. 

A  very  common  and  pretty  little  flnch  is  often  seen 
hopping  about  on  the  ground  at  Entebbe  and  Jinja ; 
of  a  reddish  pink  or  old  rose  colour,  it  is  often  nicknamed 
the  "  animated  plum."  It  is  about  the  size  of  a  red  plum, 
and  agrees  with  one  very  well  in  hue. 

Another  species,  much  like  it  in  habits  and  shape,  is 
grey  and  blue.  Neither  of  these  have  been  met  with  on 
the  islands. 

The  pretty  little  Sunbirds  (Nectarirdidae)  are  abundant 
on  the  islands,  though  I  know  not  how  many  species  are 
found  there.  On  certain  very  small  islets  they  and  wagtails 
are  the  chief  part  of  the  bird  fauna,  but  this  depends  upon 
whether  their  favourite  food  plant  is  there.  This  is  a 
labiate,  which  sends  up  tall  stems  bearing  scarlet  flowers 
arising  from  a  knob.  These  knobs  are  set  at  intervals 
up  the  stem,  and  when  the  flowers  are  withered  and  the 
seeds  develop  are  unpleasantly  spiky  to  knock  against. 

Wherever  a  cluster  of  these  plants  grows,  a  sunbird 
is  sure  to  be  seen  clinging  on  to  the  stem  and  thrusting 

13 


178  BIRDS 

its  slender  bill  down  the  tubes  of  the  flowers  one  after 
another. 

There  is  no  doubt,  however,  that  they  also  eat  insects, 
or  at  any  rate  spiders.  I  have  seen  one  hovering  in  front 
of  a  web  spun  amongst  tall  stems  of  grass  and  delicately 
picking  o£f  the  spider  that  sat  in  the  centre  of  it. 

On  the  other  hand,  a  sunbird  was  once  found  hopelessly 
entangled  in  the  strong  sticky  threads  of  a  web  of  a  Nephila 
spider,  the  sheets  of  whose  webs  are  so  unpleasantly 
abundant  on  many  of  the  islands.  Fortunately,  I  was 
able  with  a  stick  to  reach  up  and  set  the  bird  free.  The 
cock  bird  is  a  beautiful  little  creature,  the  prevailing  hue 
being  rich  metallic  green,  but  different  species  have  the 
throat  and  breast  of  brilliant  scarlet  or  other  bright 
colours  ;  the  hen  bird  is  dull  brown  or  grey.  As  is  usually 
the  case  with  brilliantly  coloured  birds,  the  song  is  not 
musical,  but  it  is  quite  a  pleasing,  lively  little  twitter. 

They  are  pugnacious  birds,  and  may  often  be  seen 
chasing  each  other  with  angry  scoldings,  and  I  have 
watched  them  chasing  away  the  huge  Carpenter  bees  from 
the  attractive  flowers  of  a  bush. 

Ths  Warblers  must  be  passed  over,  since  I  have  no 
ornithological  knowledge  of  them  ;  but  there  is  one 
species  that  is  very  familiar,  since  it  inhabits  the  low 
bushes  in  the  forest  and  its  sharp  chirp  is  heard  every- 
where. It  has  the  appearance  and  manner  of  a  wren, 
with  short  upturned  tail,  and  is  constantly  in  evidence 
climbing  about  among  the  branches  on  which  it  hunts  for 
sedentary  insects,  or  angrily  chasing  away  another  which 
is  trespassing  on  its  feeding  grounds.  It  is,  I  think, 
more  abundant  on  the  islands  than  on  the  mainland. 

The  Thrush  family  deserves  mention  on  account  of  the 
fine  songster  Cossypha,  (possibly  heuglini,)  or  Robin  Chat 
(E'nyonza),  which  abounds  in  the  forests.  It  is  a  handsome 
bird,  but  one  seldom  seen,  as  it  is  of  retiring  habits  and 
rarely  leaves  the  sheltering  bushes.     Occasionally  one  gets 


COSSYPHA  179 

a  glimpse  of  its  bright  orange  under  side,  with  dark  back 
and  white  streak  on  the  head.  Its  mellow  voice  reminds 
one  in  a  way  of  the  blackbird  ;  but  it  has  a  unique  method 
of  singing  as  if  for  its  own  enjoyment,  quietly  and  in  a 
thoughtful  way;  there  is  no  "fine  careless  rapture."  It 
is  an  extraordinarily  clever  mimic,  and  in  the  evenings 
one  can  hear  it  copying  the  notes  of  fish  eagle,  owl,  blue 
kingfisher,  cuckoo,  and  doubtless  many  other  birds  as 
well,  introducing  the  well  known  notes  into  its  own  steady 
flow  of  music. 

Song  thryshes,  obviously  closely  allied  to  the  English 
songster,  are  abundant  at  Entebbe,  where  their  music 
brings  up  memories  of  home  ;  but  they  are  only  occasion- 
ally heard  on  a  few  of  the  islands.  Kibibi,  Kiuwa  and 
Kizima  were  noted  as  having  these  birds. 


CHAPTER   IX 

REPTILES    AND    FISH 

A  BOOK  about  life  on  the  Victoria  Nyanja  may  reasonably 
be  expected  at  least  to  mention  the  crocodile,  known  to 
the  natives  as  "  E'gonya," 

His  scarcity  was  what  one  noticed  most,  for  which  a 
reason  will  be  suggested  later.  One  had  read  so  much 
about  crocodiles  in  tropical  rivers  lying  thickly  on 
the  mud,  and  in  great  numbers  in  the  water,  that  one 
had  expected  to  see  the  same  in  the  lake.  This  was  far 
from  being  the  case,  and  it  soon  became  clear  that  one 
or  two  could  usually  be  seen  on  any  day  frequenting 
the  same  haunts,  but  that  it  was  possible  to  go  long  dis- 
tances and  never  see  a  crocodile,  and  young  specimens 
are  rarely  seen. 

Their  favourite  haunts  are  of  two  kinds — a  stretch  of 
coastline  fringed  with  rushes  and  reeds  growing  in  shallow 
water,  wherein  they  lie  with  only  the  top  of  the  head 
and  scaly  ridge  of  the  back  and  tail  showing,  or  an  open 
shore  of  rock  or  sand  on  which  they  warily  bask.  Near 
my  camp  on  Bugalla  the  northern  bay  furnished  a  haunt 
of  the  first  Idnd,  and  a  large  crocodile  could  nearly  always 
be  seen  there.  Ngamba  and  Tavu  Islands  provided 
rocky  basking  places,  and  a  favourite  large  rock  on  the 
east  side  of  Tavu  was  seen,  whenever  visited,  to  have 
one  or  more  crocodiles  basking  on  it,  and  on  one  occasion 
seven  were  seen  there,  which  was  the  greatest  number 
ever  seen  together.     It  was  amusing  to  see  these  huge 

180 


CROCODILES  181 

antiquated  reptiles  take  alarm  as  soon  as  the  canoe  drew 
near,  and  plunge  headlong  into  the  water  ;  they  were 
always  off  before  one  got  near  enough  to  take  a  photo- 
graph. 

It  seems  strange  that  such  a  huge  and  well  defended 
creature  should  be  so  nervous.  On  the  only  occasion 
when  I  have  got  within  camera  range,  of  course  I  had 
no  camera  with  me.  On  the  northern  coast  of  Ngamba 
I  was  pushing  my  way  through  rocks  and  dense  bushes 
Avhen  I  suddenly  heard,  apparently  right  in  front  of  my 
feet,  a  horrid  noise,  half  hiss,  half  snarl.  Hastily  stumbling 
back,  I  saw  I  had  nearly  stepped  on  the  head  of  a  large 
crocodile  lying  on  the  ground.  I  remained  still  and 
watched,  noting  Tse-tse  fly  feeding  on  him,  and  wondered 
why  he  did  not,  as  usual,  rush  headlong  into  the  water. 
Before  going  away  I  threw  a  lump  of  rock  on  to  his  back, 
but  that  did  not  move  him  ;  he  merely  hollowed  his  back, 
raising  head  and  tail  in  the  air,  and  with  mouth  wide 
agape  gave  a  sort  of  bellow.  Possibly  he  was  sick  or 
was  exhausted  from  fighting,  for  there  was  an  ulcerated 
wound  at  the  base  of  his  tail.  On  the  same  island  at 
a  later  date  I  saw  another  large  crocodile  with  a  similar 
wound,  but  on  the  opposite  side,  and  wondered  if  this 
had  been  the  partner  of  the  duel. 

Crocodiles  deposit  their  eggs  in  a  hole  scooped  in  a 
dry  sandy  beach  ;  these  are  afterwards  carefully  covered 
over  to  a  depth  of  about  a  foot,  and  one  often  sees  the 
imprint  of  the  body  of  the  mother  on  the  soft  sand,  even 
the  pattern  of  the  scales  on  the  belly  being  clearly  shown, 
so  that  it  appears  that  the  parent  returns  to  visit  the 
nest,  though  she  does  not  seem  to  be  very  successful 
in  protecting  the  eggs,  as  will  be  seen  later. 

During  1914  numbers  of  nests  were  found,  of  which 
a  list  is  given  below  :  the  number  of  eggs  varies  little, 
averaging  sixty  in  one  nest.  No  evidence  was  obtained 
that  more  than  one  crocodile  lays  eggs  in  one  nest. 


182 


REPTILES   AND   FISH 


The  period  required  for  development  is  stated  to  be 
twelve  weeks. ^ 


Where  Found. 

Date. 

Number 
of  Eggs. 

State  of  Development. 

1.  Marida    .  . 

Feb.  21 

58 

/33  almost  ready  to  hatch. 
\25  shrivelled  and  undeveloped. 

2.  Masovwi 

March  6 

59 

Embryos  about  i  grown. 

3.  Kizima   .  . 

March  11 

60 

Embryos  about  J  grown. 

4.  Bulago    .  . 

March  14 

64 

Embryos  about  J  grown. 

5.  Tavu 

June  17 

60 

Freshly  laid. 

6.  Kimmi    .  . 

June  30 

59 

Laid  between  June  23-30. 

7.  Kimmi    .  . 

July  6 

69 

Laid  between  June  30-July  7. 

S.  Bulago    .  . 

July  24 

66 

] 

9.  Bulago    . . 

July  24 

57 

>Laid  between  July  17-24. 

10.  Bulago    .  . 

July  24 

76 

J 

11.  Tavu       .. 

August  18 

65 

1 

12.  Tavu 

August  18 

48 

>Laid  between  July  30-August  18. 

13.  Tavu 

August  18 

38 

J 

Note. — Only  in  the  first  case  was  every  egg  examined,  and  the  number 
that  had  failed  to  develop  is  surprising.  In  view  of  this  fact  it  is  to  be 
regretted  that  subsequently  only  a  few  from  each  nest  were  broken  open. 


The  Monitor  Lizard. 

By  far  the  most  notable  reptile  on  the  islands  is  the 
enormous  Monitor  Lizard  {Varanus  niloticus),  called  by 
the  natives  "  Enswa-swa."  It  is  of  a  dull  grey  colour 
speckled  with  yellow,  and  its  long  tail  is  flattened  from 
side  to  side  for  swimming.  This  fine  creature  may 
measure  almost  six  feet  from  nose  to  tail  tip.  It 
is  never  found  far  from  the  water,  into  which  it  rushes 
headlong  when  disturbed,  so  that  its  panic-stricken  flight 
is  very  often  heard  as  one  pushes  through  the  dense 
vegetation  bordering  the  shore.  In  the  water  the  Enswa- 
swa  swims  with  vigorous  strokes  of  the  flattened  tail, 
and  may  often  be  seen  lazily  sculling  itself  along  with  the 
top  of  the  head  just  above  the  surface.  When  alarmed 
it  hastily  dives,  and  can  remain  under  water  for  a 
^  Gadow,  Cambridge  Natural  History,  vol.  Reptiles,  p.  465. 


A    CANOE-MAN    AND    AN    "  ENS\VA-S\VA  "   JUST   CAUGHT. 


To  face  p.  182. 


VARANUS  183 

surprisingly  long  time.  Like  the  crocodile,  Varanus  has 
favourite  basking  places  on  the  rocks,  choosing  preferably 
a  place  where  ferns  grow,  on  which  it  lies  ;  but  curiously 
enough  if  one  is  tethered  in  the  sun  it  dies,  apparently 
from  exposure,  in  an  hour  or  so. 

Crocodiles  are,  as  has  been  said,  scarce  among  the 
islands,  but  Varanus  is  very  abundant,  and  must  have 
increased  in  number  very  greatly  since  the  removal  from 
the  islands  of  the  natives,  among  whom  skins  of  Enswa- 
swa  are  in  great  request  for  making  the  long  narrow 
"  Engabi  "  drums,  which  are  beaten  by  the  hand  at  con- 
vivial gatherings  or  weddings.  But  though  the  Enswa- 
swa  are  abundant  enough,  one  does  not  often  meet  with 
their  nesting  places  ;  the  only  three  that  I  ever  saw  were 
a  sandy  patch  of  open  ground  on  the  north  side  of  Kimmi 
Island,  where  burrows  and  fragments  of  old  eggshells 
were  found,  a  regular  warren  in  sandy  soil  on  Busiri, 
and  a-  similar  place  on  the  south  end  of  Sindiro  Isle. 
Occasionally  I  saw  very  young  Enswa-swa  close  to  the 
water  sunning  themselves  on  little  branches  like  any 
other  lizard,  but  I  do  not  think  the  adult  climbs  up  trees  ; 
it  appears  to  be  an  instance  of  the  losing  by  an  adult 
of  an  ancestral  habit  retained  in  youth.  A  curious 
inverted  ratio  was  found  to  exist  between  the  members 
of  crocodiles  and  Enswa-swa  on  any  particular  islet :  during 
the  tour  at  the  commencement  of  1914  it- was  noted  that  if 
many  Enswa-swa  were  seen  there  were  very  few  crocodiles, 
and  vice  versa.  Thus,  on  Tavu  Island,  where  more 
crocodiles  were  seen  than  on  any  other  island,  Enswa- 
swa  were  exceptionally  scarce  ;  this  was  verified  by  many 
visits  and  work  on  the  island.  On  the  other  hand,  when 
Rumfua  was  visited,  during  the  examination  of  its  shores 
from  a  canoe  five  Varanus  but  no  crocodiles  were  seen. 
It  must  be  admitted,  however,  that  Rumfua  was  only 
visited  once.  Isentwa  was  noted  to  have  abundant 
Enswa-swa,  but  no  crocodiles  were  seen  there.     Although 


184  REPTILES   AND   FISH 

it  will  be  shown  below  that  Varanus  has  a  profound 
influence  upon  the  number  of  crocodiles,  yet  it  is  not 
clear  how  the  reverse  can  be  the  case.  Varanus  seems 
to  enjoy  a  varied  diet.  The  stomach  of  one  was  found 
to  contain  two  slugs  and  the  shell  of  an  operculate  fresh- 
water mollusc,  and  collections  of  shells  of  the  large  water 
snail  Ampullaria  are  often  seen  on  the  shore  broken  on 
a  rock  as  garden  snails  are  broken  by  thrushes. ^ 

I  have  seen  a  young  Varanus  biting  off  the  juicy  lower 
part  of  the  stems  of  rushes  ;  natives  say  they  eat  fish, 
and  on  one  occasion  when  my  boys  were  walking  a  little 
ahead  on  the  shore,  one  of  them  saw  an  Enswa-swa  run 
away  from  a  piece  of  dead  fish.  On  one  occasion  at 
Jinja  a  scnall  bird  that  I  had  shot  fell  down  almost  on 
top  of  an  unperceived  Enswa-swa,  who  at  once  picked 
it  up  and  ran  away  with  it,  shaking  the  struggling  bird 
as  a  terrier  shakes  a  rat. 

The  most  important  food  of  Varanus,  so  far  as  man  is 
concerned,  is  the  egg  of  the  crocodile,  and  there  is  no 
doubt  whatever  in  my  mind  that  the  increase  of  Varanus 
on  the  islands  since  the  depopulation  must  eventually  have 
a  powerful  effect  in  reducing  the  number  of  crocodiles 
there.  Thus  on  July  30,  1914,  on  Tavu  Island,  two 
crocodiles'  nests  previously  noted  there  were  found  to 
have  been  disturbed  ;  holes  had  been  dug  and  a  crushed 
egg  was  lying  on  the  sand.  On  Bulago  Island,  on 
August  1st,  two  nests  previously  noted  were  found 
ravaged  and  crushed  eggs  lay  all  round.  At  another  point 
a  nest  of  seventy-six  eggs  that  had  been  found,  freshly  laid, 
on  July  24th,  had  been  absolutely  cleared  out  and  not 
one  was  left.  In  seven  days  eggs  had  been  accounted 
for  at  the  rate  of  eleven  a  day,  which  would  seem  to  be 
more  than  one  Enswa-swa  could  accomplish  !  In  fact, 
no  nest  of  crocodiles'  eggs  tvhich  I  visited  a  second  time 

^  This  may,  however,  be  entirely  the  work  of  the  open-bill  stork.  See 
Chapter  VIII. 


VARANUS   AND   CROCODILE'S   EGGS        185 

ivas  found  to  have  been  left  undisturbed.  Though  I  have 
not  actually  seen  Varanus  devouring  the  eggs,  there  is 
no  doubt  of  it  from  the  tracks  they  leave  in  the  sand 
all  round  and  over  the  nest,  and  my  friend  Dr.  Lyndhurst 
Duke  told  me  that  he  had  actually  seen  one  digging 
away  at  a  nest.  It  therefore  appears  that  strict  protec- 
tion oi  Varanus  against  slaughter  by  natives  should  be  an 
effectual  method  of  keeping  down  the  numbers  of  croco- 
diles. The  importance  of  Varanus  as  a  food  supply  of 
Glossina  has  been  alluded  to  in  the  chapter  on  the  Tse-tse, 

A  fine  large  lizard  of  the  family  Agamidae  is  known 
as  "  E'konkomi  "  by  the  natives.  It  has  a  brightly 
coloured  male  partly  sky  blue,  the  female  being  grey. 
They  particularly  frequent  open  places,  but  prefer  to 
have  a  large  tree  in  the  neighbourhood,  up  which  they 
run  when  alarmed.  The  E'konkomi  seems  to  feed  very 
largely  on  ants,  judging  by  the  remains  found  in  its 
excreta,  and  from  the  contents  of  the  stomachs  examined 
in  several  specimens.  It  has  to  a  marked  degree 
the  habit  that  may  be  seen  in  many  lizards,  alternately 
raising  and  lowering  the  body  between  thfe  fore  limbs,  as 
is  done  by  a  man  lying  prone  on  the  ground  in  a  common 
gymnastic  exercise.  I  could  never  make  out  the  sig- 
nificance of  this  habit,  though  I  think  it  is  developed 
to  a  greater  degree  in  the  male  sex. 

Smaller,  more  slender  lizards  (Lacertidae)  played  on 
the  roof  of  my  tent,  and  from  inside  I  could  wateh  their 
shadows  as  they  scuttled  about.  It  was  most  amusing 
to  see  them  playing  :  one  would  stealthily  creep  up 
behind  another  and  bite  his  tail,  and  then  there  would 
be  a  pursuit  and  a  rushing  about  all  over  the  tent. 

They  would  dispose  themselves  for  the  night  some- 
where among  the  folds  of  the  tied-back  doorv/ay,  and 
on  one  occasion  I  was  awakened  by  hearing  their  well 
known  pattering  feet  on  the  roof.  Realizing  that  some- 
thing must  have  turned  them  out  from  their  sleeping 


186  REPTILES   AND   FISH 

place,  I  lit  a  lamp  and  found  that  a  column  of  the  "  Safari 
ant  "  {Dorylus)  had  directed  its  attention  to  that  part 
of  the  tent,  but  fortunately  for  my  night's  rest  they  did 
not  investigate  my  bed. 

The  little  grey  Gecko,  with  discs  on  its  toes  enabling 
it  to  run  upside  down  on  ceilings  and  walls,  was  not  seen 
in  my  huts  on  the  islands,  although  common  enough  on 
the  mainland  ;  but  I  do  not  mean  to  state  that  it  did  not 
exist  on  the  islands. 


Tortoises. 

Like  crocodiles,  tortoises  are  less  plentiful  than  might 
be  expected.  The  numerous  isles  of  varying  size  furnish 
abundant  areas  with  marshy  shore  and  shallow,  rush- 
grown  water,  which  appear  eminently  suitable  for  water 
tortoises,  yet  it  was  many  months  before  I  saw  one — a 
flat,  black,  short  tailed  Species  that  wanders  about  near 
the  water's  edge.  One  species  of  land  tortoise  is  occasion- 
ally seen  ;  the  natives  call  it  "  Enfudu,"  a  name  that 
seems  to  carry  with  it  a  suggestion  of  blundering  stupidity 
not  altogether  foreign  to  a  tortoise.  It  is  somewhat 
larger  than  the  European  species  kept  in  gardens,  and 
has  a  high  domed  shell,  with  the  anterior  and  posterior 
portions  of  the  ventral  plate  hinged  so  as  to  be  capable 
of  a  little  movement.  I  once  found  a  specimen  that  had 
apparently  been  dropped  from  a  height  ;  it  was  a  large 
one,  and  the  highest  part  of  the  dome  of  the  shell  had 
been  fractured,  a  portion  being  depressed.  It  had  probably 
been  destined  to  be  eaten  by  some  bird  of  prey,  which  had 
been  frightened  away  at  my  approach,  for  the  blood  on 
the  wound  was  still  fresh.  So  there  may  be,  after  all, 
some  truth  in  the  old  legend  which  ascribes  the  death 
of  a  Greek  sage  to  the  impact  of  a  tortoise  dropped  upon 
his  bald  head  by  a  bird  of  prey,  which  mistook  the  shining 
cranium  for  a  stone  ! 


SNAKES  187 


Snakes. 


During  one's  wanderings  through  thick  grass  and 
among  bush  and  rocks  one  frequently  came  across  snakes 
hastily  retreating  as  one  ajDproached. 

It  seems  to  be  a  fixed  idea  with  some  people  that  a 
snake's  main  object  in  life  is  to  find  a  human  being  and 
bite  him.  I  take  the  opposite  view,  that  so  far  as  man  is 
concerned  the  snake  is  chiefly  occupied  with  avoiding 
him  lest  he  do  the  snake  harm  ! 

From  the  snake's  point  of  view,  what  possible  object 
can  there  be  in  wasting  valuable  poison  by  biting  a  huge 
creature  who  cannot  be  eaten,  and  could,  even  when 
mortally  wounded,  crush  the  life  out  of  a  snake  before 
he  dies  ?  So,  hearing  some  heavy  footstep  come  crashing 
through  the  grass,  the  wise  snake  departs  as  quickly  as 
possible  lest  he  be  trodden  upon. 

This  is  where  a  booted  man  has  the  advantage  of  a 
silent-footed  native,  who  gives  no  warning,  so  that  a 
snake  half  asleep,  or  languorous  after  a  meal,  or  stupid 
and  half  blind  owing  to  an  approaching  shedding  of 
skin,  suddenly  finds  a  large  animal  almost  on  top  of  him, 
and  strikes  in  a  panic  of  self-defence. 

Once  only  I  very  nearly  trod  upon  a  large  black  snake, 
a  species  common  on  the  islands,  and  reaching  up  to  six 
feet  in  length.  I  was  walking  through  very  thick,  high 
tussocks  of  grass,  which  made  it  necessary  to  go  slowly 
and  to  lift  the  feet  high.  In  the  middle  of  one  step, 
while  my  foot  was  in  the  air,  the  snake  crawled  out  from 
a  very  dense  tussock  across  the  very  spot  for  which  my 
foot  was  destined.  It  was  fortunately  just  not  too  late 
to  put  the  foot  down  elsewhere,  and  all  was  well,  for 
the  big  snake  vanished  as  suddenly  as  it  had  appeared, 
obviously  bent  on  escaping  being  trodden  upon. 

Puff  adders,  being  very  sluggish,  will  not  get  out  of 
the  way  until  forced  to  do  so.     I  have  literally  pushed 


188  REPTILES   AND   FISH 

one  off  the  track  with  a  stick  because  it  would  not  move  ; 
a  lovely  species,  the  glossy  skin  marked  with  carpet 
pattern  of  different  shades  of  purplish  greys  and 
pinks,  soft  browns  and  creams,  harmonizing  exquisitely 
with  the  lights  and  shades  among  the  dead  leaves 
surrounding  it. 

This  was  Bitis  nasicornis,  the  puff  adder  of  forests, 
with  a  little  horn  on  each  side  of  the  nose  formed  by 
clusters  of  upright  scales.  Beautiful  as  is  its  colouring, 
the  shape  is  so  thick  and  squat  that  this  species  loses 
considerably  in  beauty  from  this  cause.  The  much  less 
ornamental  Bitis  arietans,  well  known  in  South  Africa, 
was  once  found  on  Damba  Island  by  my  canoe-men 
hidden  among  the  rocks  at  the  very  place  where  the 
canoe  was  kept.  Somehow  they  managed  to  get  a  rope 
round  it,  and  dragged  it  up  in  triumph  to  my  house. 
It  was  4  feet  6  inches  long,  and  one  could  not  but  be 
glad  to  be  rid  of  so  dangerous  a  neighbour  for  the  bare- 
footed men. 

Mention  has  been  made  of  the  booming  noise  uttered 
by  the  crowned  crane  during  the  wet  season.  My  boys, 
when  asked  what  made  the  noise,  always  replied,  "  E'sa- 
lambwa  "  (puff  adder).     Some  puffing  ! 

The  python  is  another  fine  snake,  handsomely  marked, 
and  when  in  good  condition  his  glossy  skin  is  really  beauti- 
ful. I  only  met  with  him  once,  on  Kimmi  Isle,  when  I 
came  upon  a  small  specimen  about  six  feet  long  lying 
on  a  marshy  bit  of  shore.  I  watched  him  for  some  time, 
noting  two  Glossina  fly  up  from  him,  one  obviously  full 
of  blood.  After  a  while  he  became  aware  of  me,  and 
moved  slowly  away,  absolutely  silently,  with  the  dignity 
befitting  a  king  of  snakes. 

On  Ngamba  Island  a  place  was  found  where  the  dead 
leaves  in  a  circular  area  were  flattened,  and  there  was  a 
trail  of  flattened  leaves  leading  to  and  from  it.  The 
natives  said  this  was  the  resting  place  of  an  "  E'timba  " 


SNAKES  189 

(python),  which  was  probably  the  one  previously  seen 
on  Kimmi,  for  they  swim  well,  as  do  most  snakes. 

One  day  when  going  round  Tavu  Isle  in  the  canoe 
preparatory  to  landing,  I  happened  to  look  over  the  side 
and  saw  a  snake  swimming  very  gracefully,  with  the 
top  of  its  head  just  above  water.  It  soon  took  fright, 
dived,  and  was  lost  to  sight  in  the  deep  water.  It  appeared 
to  be  a  young  python  about  two  feet  long. 

Another  snake  which  on  account  of  its  beauty  particularly 
calls  for  mention  is  a  harmless,  slender,  grass  green  species 
often  seen  on  the  lake  shore  hunting  for  frogs,  whose 
pitiful  cry  when  once  heard  is  always  recognizable  again. 
The  brilliant  grass  green  colouration  and  very  graceful 
movements  of  this  snake  always  evoked  one's  admiration. 

A  similar  bright  green  species  might  sometimes  be  seen, 
high  up  among  the  branches  of  trees,  sometimes  travelling 
rapidly  and  almost  leaping  across  gaps  too  big  to  be 
spanned.  The  manner  in  which  it  seemed  to  spring 
across  from  one  tree  to  another  is  very  interesting,  seeing 
that  in  the  Malay  Archipelago  certain  snakes  have  carried 
the  process  further,  and  take  gliding  flights  from  a  high 
to  a  lower  branch.^ 

The  last  snake  to  be  mentioned  is  a  very  curious 
and  interesting  species,  which  was  once  found  deeply 
buried  in  the  base  of  a  termite  hill  which  was  being 
demolished.  It  was  about  twelve  inches  long,  greenish 
grey  in  colour,  very  smooth,  and  could  move  back- 
wards or  forwards  equally  well.  The  eyeless  head  was 
so  small  that  the  slightly  swollen  posterior  extremity, 
ending  in  a  blunt  spike,  was  larger.  When  handled  the 
snake  pressed  this  blunt  spike  forcibly  against  one's  hand  ; 
doubtless  an  ignorant  person  would  have  dropped  it, 
thinking  it  was  biting  or  "  stinging."  These  snakes  are 
entirely  subterranean,  and  are  found  both  in  Asia  and 
Africa  ;  presumably  they  live  on  worms  and  burrowing 
^  Shelford,   A   Naturalist  in   Borneo,   pp.    79-82. 


190  REPTILES   AND   FISH 

insects,  possibly  on  termites  also.  This  specimen  much 
resembled  one  of  the  legless  lizards  found  under  stones 
or  logs  of  wood,  which  the  Baganda  call  "  Namugoya," 
and  the  English  "  blind  worm  "  or  "  slow  worm,"  in  spite 
of  their  bright  eyes  and  often  quite  active  movements. 
The  "  Namugoya  "  is,  of  course,  regarded  by  the  natives 
as  a  snake,  and  therefore  on  no  account  to  be  touched. 

Frogs  and  Toads. 

Frogs  have  already  been  mentioned  as  contributing  to 
the  sounds  heard  on  the  islands.  The  species  most  often 
seen  on  the  shore  much  resembles  the  European  "  Green 
tree  frog,"  and  may  be  found  freely  exposed  to  the  sun 
on  leaves  or  branches.  It  adapts  its  colouration  to  the 
intensity  of  the  illumination,  and  in  very  light  surroundings 
becomes  very  light  golden  green  or  even  milk  white. 
Among  dark  surroundings  it  is  greenish  black,  but  does 
not  assume  brown  tints.  Another  tree  frog,  very  much 
smaller,  seems  to  be  responsible  for  the  shrill  tinkling 
noise,  like  sleigh  bells,  always  heard  among  reeds  and 
rushes  after  sunset.  The  green  frogs  are  devoured  by 
the  green  grass  snake  previously  described,  and  their  cry, 
when  caught,  is  pitiful,  and  surprisingly  like  that  of  a 
child. 

Another  species — possibly  a  toad — which  is  also  much 
to  the  liking  of  snakes  is  larger,  and  has  a  rough  brown 
skin  ;  it  lives  by  day  in  burrows  which  it  digs  where  the 
soil  is  suitably  light.  A  green  snake  was  seen  one  day 
with  its  head  down  one  of  these  burrows  attempting  to 
swallow  the  occupant,  and  as  the  mouth  of  the  burrow 
was  large  and  the  snake  thin,  I  was  able  to  look  past 
the  snake  and  see  how  the  toad  had  distended  itself  with 
air  to  such  an  extent  that  the  snake,  with  mouth  wide 
agape,  could  not  get  a  grip  on  the  spherical  surface. 
Though  it  persevered  for  an  hour,  with  jaws  so  widely 
apart  that  upper  and  lower  jaws  were  almost  in  a  straight 


A    SMALL    "  ENSWA-SWA." 


A    VERY    ABUNDANT    TREE    FROG. 


To  I  ace  p.  190. 


SNAKES   AND   FROGS  191 

line,  it  could  do  no  more  than  merely  apply  itself  to  the 
toad's  side,  and  eventually  had  to  give  up  the  attempt 
to  swallow  such  an  unmanageable  victim  !  I  got  the  toad 
out,  and  save  for  a  few  scratches  made  by  the  snake's 
teeth  it  was  none  the  worse,  and,  having  deflated  itself, 
crawled  away  quite  calmly  as  if  this  were  no  unusual 
experience  ! 

It  was  interesting  to  see  the  toad  actually  save  its  life 
by  its  power  of  increasing  its  size,  and  one  wonders  why 
the  snake  had  not  caught  hold  of  a  limb.  Had  the  snake 
been  a  poisonous  species,  the  prey  would  have  been  killed 
by  contact  with  the  fangs,  and  even  had  it  been  able 
first  to  inflate  itself,  its  subsequent  death  would  have 
ensured  its  return  to  normal  size. 

This  brings  up  a  point  which  had  always  been  a  difficulty 
to  me  until  I  meditated  over  this  and  other  observations. 
If  the  poison  has  been  evolved  by  slow  degrees  from  the 
ordinary  non-poisonous  saliva,  how  could  this  have  been 
brought  about  ?  What  use  could  slightly  venomous 
saliva  be  to  a  snake  ?  For  a  creature  thus  bitten  might 
still  be  able  to  go  away  a  long  distance  and  die  later, 
where  the  snake  would  not  find  it.  A  clue  was  given  me 
during  active  service  in  German  East  Africa,  where  I 
first  met  with  the  handsome  snake  called  "  Boomslang  " 
by  the  Boers,  and  was  discussing  the  debated  question 
whether  or  no  it  is  poisonous.  One  old  Boer  told  me  he 
had  seen  one  bite  a  man's  arm,  which  afterwards  swelled 
up  dreadfully,  although  the  effects  were  not  serious  ;  but 
many  Boers  said  it  was  not  poisonous.  This  snake  is 
an  "  Opisthoglyph,"  i.e.  it  has  not  the  long  fangs  of  a 
viperine  snake,  but  some  of  the  back  teeth  are  grooved 
in  part  of  their  length,  and  a  fold  of  mucous  membrane 
forms  a  pouch  round  the  groove  to  conduct  the  slightly 
poisonous  saliva  while  the  snake  mouths  its  prey,  for  it 
does  not  strike  and  let  go.  Now  it  is  easy  to  see  what  an 
advantage  it  would  be  to  a  snake  if,  whilst  it  was  hold- 


192  REPTILES   AND  FISH 

ing  on  to  struggling  prey,  the  latter  should  be  weakened, 
even  only  a  little,  by  injection  of  slightly  poisonous  saliva, 
for  the  prey  would  then  be  more  easily  swallowed.  Having 
started  thus  one  can  see  how  the  poisonous  quality  could 
be  developed.  For  the  more  quickly  the  struggling 
animal  succumbed,  the  less  time  would  the  snake  need 
to  hold  on  to  it,  and  the  less  chance  would  there  be  of 
its  escaping,  until,  with  the  increasing  strength  of  the 
venom,  a  stage  would  be  reached  when  the  snake  would 
only  need  to  strike  once,  and  quietly  wait  a  few  minutes 
until  the  prey,  at  once  seriously  poisoned,  falls  helpless 
and  dies. 

An  extremely  interesting  observation  is  here  quoted 
from  a  letter  in  Nature  by  Professor  Poulton,  dated 
January  2,  1918.  Professor  Poulton  quotes  the  observation 
for  another  purpose,  but  it  is  so  exactly  illustrative  of  my 
point  that  it  is  here  repeated.  Dr.  G.  A.  K.  Marshall 
says  :  "  When  happening  to  look  over  a  low  stone  wall 
near  Estcourt,  Natal,  in  1897,  I  chanced  to  observe  a 
small  snake  in  the  very  act  of  striking  a  frog.  After  being 
bitten  the  latter  hopped  of!  at  a  great  pace,  and  I  was 
rather  siirprised  to  see  that  the  snake  made  no  attempt 
at  pursuit,  but  merely  followed  in  a  very  leisurely  manner  " 
(the  italics  are  mine).  "  Seeing  that  the  frog  had  come  to 
a  standstill  at  a  considerable  distance  ofif,  I  crept  along 
under  the  wall  so  as  not  to  disturb  the  snake,  and  on 
getting  near  the  frog  I  looked  cautiously  over  the  wall 
to  see  the  end  of  the  tragedy.  The  snake  was  still 
some  way  behind,  approaching  steadily,  and  on  reaching 
its  victim  stood  watching  it  for  some  moments  with 
its  head  raised,  the  frog  meanwhile  sitting  trembling 
in  front  of  it.  At  last  the  snake  seized  its  prey  and  suc- 
ceeded in  swalowing  it  after  hut  feeble  resistance.  It 
seemed  clear  that  the  trembling  and  inability  to  escape 
on  the  part  of  the  frog  were  simply  due  to  the  action  of 
the  poison  injected  at  the  first  bite." 


>V:">.     ;     W 


,Ji 


0\E    OF    THE    FLY    BOYS    HOLDING    A    SMALL     "  JLA.MBA  "    (lUXG    FISH). 


"SEMUTUNDU." 
Foot-rule  to  show  scale. 


To  face  p.  192. 


MAIVIBA   AND   MALE  193 

The  only  remark  I  would  pass  on  this  most  apt  observa- 
tion is  that  we  have  no  statement  from  Dr.  Marshall 
whether  the  snake  really  was  a  poisonous  one  :  it  is  only 
presumed  to  be  so  from  the  effects  of  the  bite. 

Fish. 

The  most  noteworthy  fish  of  the  lake  is  the  Lung  Fish 
(Protopterus),  known  to  the  Baganda  as  '*  E'mamba,"  and 
a  favourite  article  of  food  with  them.  It  attains  a  large 
size,  up  to  five  feet  long,  and  has  a  flattened  body  with 
broad  tapering  tail,  furnished  with  a  wavy  fin  along  both 
dorsal  and  ventral  edges.  The  Baganda  spear  the  mamba 
in  shallow  water,  but  it  may  frequently  be  met  with  in 
deep,  open  water,  coming  up  to  the  surface  to  breathe 
in  the  same  way  as  does  a  tadpole.  On  one  occasion 
a  mamba  appearing  just  behind  the  stern  of  the  canoe 
in  which  I  was  sitting  emitted  the  used-up  air  from  its 
lungs  with  such  a  loud  grunt,  that  I  turned  round  expecting 
to  see  a  hippopotamus  ! 

Having  taken  a  new  breath,  the  mamba  turns  on  its 
side  and  gives  a  peculiar  heave  of  its  flat  tail  as  it  dives 
down  again,  but,  being  very  conspicuous,  it  is  quickly 
perceived  by  a  soaring  fish  eagle,  who  stoops  to  secure  it. 

Probably  they  spawn  during  the  rainy  season  in  shallow 
water,  for  shortly  after  the  heavy  rains  the  young  may 
be  found  there.  I  did  not  find  the  tough  flesh  of  the 
mamba  worth  eating,  but  that  of  a  species  of  Siluridae, 
called  "  E'male  "  by  the  natives,  is  as  good  as  any  fish 
I  know.  It  is  commonly  called  "  Mud-fish  "  by  the 
English,  but  specimens  caught  in  the  open  waters  around 
the  islands  had  no  suspicion  of  muddiness,  and  the  firm, 
boneless  white  flesh  was  most  excellent  eating.  The  Male 
has  a  flat,  broad  head  covered  with  bony  plates  (see  Fig.), 
and  has  long  barbels  round  the  mouth.  The  body  is 
somewhat  cylindrical ;  it  may  measure  two  feet  or  a  little 
over. 

14 


194  REPTILES   AND   FISH 

The  Baganda  are  fond  of  eating  a  small,  very  bony 
fish  that  haunts  shallow  water  ;  they  call  it  "  E'nkeje," 
and  fish  for  it  with  rod  and  line,  and  then  spike  a  number 
on  a  sharp  stick  and  dry  them  in  the  sun.  This  fish  is 
also  much  relished  by  kingfishers  ;  it  may  be  a  species 
of  perch.  I  saw  one  in  shallow  water  off  a  sandy  shore 
very  busily  excavating  a  funnel  shaped  pit  in  the  sand. 
With  great  vigour  it  would  push  its  snout  along  the  bottom 
until  its  mouth  was  filled  with  sand,  and  then  swim  a 
little  way  away  and  discharge  the  load.  Whether  this 
was  destined  for  a  spawning  place  I  know  not,  but  the 
fish  furiously  drove  away  any  too  inquisitive  neighbours. 

A  very  curious  fish  is  termed  "  E'mbegede  "  by  the 
natives.  It  has  a  tubular  snout  turned  down  at  right 
angles,  and  presumably  obtains  its  food  from  mud.  I 
saw  the  remains  of  one  on  Kimmi  that  had  probably 
been  caught  by  an  otter. 

Other  fish  well  known  to  the  natives  are  the  "  Semu- 
tundu,"  a  fish  with  long  barbels,  smaller  than  the  Male, 
but  much  the  nicest  to  eat  ;  a  very  large  Silurid,  called 
"  Akasonzi  "  ;  a  species  commonly  sold  in  the  market, 
and  much  eaten  by  the  English  population  at  Entebbe, 
called  **  Ensoga,"  which  somewhat  resembles  the  roach  ; 
the  beautiful  but  bony  "  Ekisinja,"  a  barbel  of  deep  olive- 
green  colour,  usually  caught  with  rod  and  line  in  shallow 
water  where  ambatch  grows  ;  and  a  small,  very  beautiful 
silvery  species  netted  in  shallow  water,  called  "  Omukene  " 
— it  is  about  the  size  of  a  minnow. 


CHAPTER  X 

THE    COLOURATION    OF    INSECTS 

The  study  of  the  colouration  of  insects  has  been  attracting 
more  and  more  attention  from  evolutionists,  whether  of 
the  Darwinian  or  Mutationist  school,  since  Bates  ^  and 
Fritz  Muller  2  in  South  America,  Wallace  ^  in  the  Malay- 
Archipelago,  and  Trimen  4  in  South  Africa  gave  the  first 
explanation  of  the  phenomena  now  known  as  Mimicry, 
and  interpreted  by  these  naturalists  on  the  lines  of  Dar- 
win's hypothesis. 

In  this  chapter  examples  will  be  given  which  have 
come  within  my  own  experience  on  the  Sesse  Islands, 
and  an  attempt  will  be  made  to  show  how  the  Darwinian 
explanation  is  more  satisfactory  than  that  of  the  Muta- 
tionist. 

In  1890  Poulton  classified  the  colours  of  animals  in 
one  scheme,  embracing  Apatetic  or  "  Deceitful  "  colours  ; 
Sematic  or  "  Warning  "  colours;  and  Epigamic  or  "  Court- 
ship "  colours.^  The  first  two  headings  only  will  be  dis- 
cussed. 

Apatetic  colours  are  divided  into  Cryptic  and  Pseudo- 

^  "  Contributions  to  an  Insect  Fauna  of  the  Amazons  Valley."     H.  W. 
Bates,  Trans.  Linn.  Soc,  vol.  xxiii,  1862,  Pt.  III. 
*  Proc.  Ent.  Soc.  Lond.,   1897,  p.  xx. 

3  "  On  the  Phenomena  of  Variation  and  Geographical  Distribution 
as  illustrated  by  the  Papilionidae  of  the  Malayan  Region."  A.  R.  Wallace, 
Trans.  Linn.  Soc,  vol.  xxv,  Part  I,   1865. 

4  Roland  Trimen,  "  On  Some  Remarkable  Mimetic  Analogies  among 
African  Butterflies."     Trans.  Linn.  Soc.  xxvi,   1870,   Part  III,   1869. 

^  The  Colours  of  Animals,  1890. 

195 


196  THE   COLOURATION   OF  INSECTS 

sematic  groups.  Cryptic  colours  are  divided  by  Poulton 
into  Procryptic  and  Anticryptic.  Procryptic  colouring 
conceals  its  wearer  from  danger,  causing  it  to  resemble 
either  the  general  surroundings  or  some  particular  part 
thereof  (Special  Procrypsis),  Instances  of  the  former, 
such  as  a  green  grasshopper  among  grass,  or  a  mottled 
grey-brown  weevil  on  earth,  are  so  numerous  and  well 
known  that  no  further  examples  need  be  mentioned. 

Special  procryptic  colouring  never  fails  to  arouse 
wonder  from  its  extreme  perfection  ;  indeed,  it  has  been 
said  that  these  resemblances  are  so  minutely  perfect  that 
Natural  Selection  cannot  possibly  have  produced  them. 

This  complimentary  doctrine  has  been  termed  Hypertely. 

Even  in  the  British  Isles  stick-like  caterpillars  abound, 
which  are  quite  indistinguishable  until  they  move.  Here 
one  must  urge  a  point  which  is  often  overlooked.  Natural 
Selection,  in  producing  special  procrypsis,  has  not  only 
altered  the  shape  and  colour  of  the  insect,  but  has  pro- 
duced deeply  seated  changes  in  the  neuro-muscular  system. 
A  stick-like  caterpillar  needs  to  maintain  itself  motionless 
for  hours  in  an  attitude  very  unusual  for  the  majority 
of  caterpillars,  and  one  which  must  require  great  develop- 
men  of  muscle  for  that  special  purpose. 

As  an  example  of  another  attitude,  very  unusual,  but 
associated  with  an  especial  scheme  of  colouring,  the 
following  is  of  interest. 

In  1910  I  found  at  Jinja,  on  the  north  shore  of  Lake 
Victoria,  a  moth,^  allied  to  our  English  Lucania,  among 
some  very  dry  dependent  spikes  of  grass  flowers,  of  a 
light  silvery  grey  tint.  The  moth  was  hanging  in  an 
inverted  position  with  wings  brought  together  over  the 
back  ;  their  under  surfaces  thus  exposed  were  of  a  silvery 
grey  hue  closely  corresponding  with  that  of  the  dried 
glumes  of  grass.  But  this  colour  was  only  shown  on  those 
surfaces   that  were    visible  ;    the   part   of    the  fore  wing 

'  A  species  of  Cirphis. 


FULL    FED   CATERPILLAR    OF   THE    NYMPHALINE    BUTTERFLY   ATERICA    GALEKE 

HANGING    FROM   THE    TIP    OF    A    FERN    FROND   JUST    BEFORE    PUPATION. 

Photographed  in  Dainba  Island  Forest. 

To  face  p.  196. 


SPECIAL   PROCRYPSIS  197 

concealed  by  the  hind  wing  was  of  a  more  usual  dull 
grey-brown  colour.  The  moth  when  disturbed  flew  away 
to  another  similar  tuft  of  grass  and  adopted  the  same 
attitude  again,  which  was  most  certainly  procryptic,  and 
very  unusual  in  a  moth  of  this  group,  the  members  of  which 
usually  rest  with  the  wings  brought  closely  against  the 
body.  The  fact  that  the  silver  grey  colour  was  confined 
to  those  parts  of  the  wings  where  it  was  necessary  for  the 
concealment  of  the  moth  by  procrypsis  is  a  very  important 
point.  Many  other  examples  of  this  nature  exist,  and  are 
arguments  against  such  protective  colouration  being  the 
result  of  mere  chance.  Natural  selection  produces  no 
more  than  is  necessary  :  this  is  contrary  to  the  doctrine 
of  Hypertely.  Exactly  similar  limitations  are  to  be  met 
with  when  studying  mimicry. ^ 

Another  beautiful  instance  of  special  procrypsis  is 
afforded  by  a  rare  Notodontid  moth,^  of  which  I  found 
a  specimen  at  rest  on  a  bush  on  Damba  Isle.  The  only 
specimen  known  up  till  then  was  the  type  in  the  British 
Museum. 

This  moth  so  closely  resembled  the  tube  formed  by  a 
dead,,  dry,  rolled-up  leaf,  that  I  was  for  long  in  doubt 
as  to  its  nature,  and  finally  had  to  pluck  the  twig  on 
which  it  sat  and  examine  the  object  most  minutely  before 
I  could  decide. 

The  wings  were  closely  folded  round  the  body ;  the 
inner  margins  of  the  fore  wings  meeting  over  the  back 
were  of  slightly  darker  tint  than  the  rest  of  tjie  wing, 
so  as  to  resemble  the  thick  midrib  of  a  dried  leaf,  whose 
petiole  was  represented  by  a  curved  tuft  of  long  hairs 
projecting  upwards  from  the  top  of  the  head. 

The  colour  of  the  wings  was  the  shining  brown  of  a 
crisp,  dry  leaf,  and  on  each  side  there  were  several  lines 
representing  venules,  and  three  doubly  ringed  markings 

*  Essays  on  Evolution,  Poulton,  p.  240. 
^  Scalmicauda  niveiplaga. 


198  THE    COLOURATION  OF  INSECTS 

like  fungus  spots.  Near  the  tip  was  an  absolutely  pure 
white  marking,  shining,  which  probably  represented  a 
silvery  patch  such  as  is  often  seen  on  a  dried  leaf.  The 
most  realistic  portion  of  the  resemblance  was  the  deception 
produced  by  the  very  dark  brown  of  the  anterior  surface  of 
the  head,  which  appeared  to  be  the  dark  shadow  of  the 
interior  of  the  tube  formed  by  the  supposed  dead  and 
rolled-up  dry  leaf. 

The  completeness  of  the  likeness  cannot  be  realized 
when  the  moth  is  seen  set  in  the  cabinet,  but  it  was  one 
of  the  most  perfect  examples  of  special  procrypsis  that  I 
have  ever  seen. 

Precisely  the  same  attitude  is  made  use  of  by  the  "  Bufif- 
tip  moth,"  but  in  this  case  the  colouring  causes  it  to 
resemble  a  short  piece  of  very  dry  stick  with  light  grey 
bark,  broken  o£E  square  at  one  end  and  obliquely  at  the 
other.  In  the  case  of  this  moth  there  is  again  to  be  noted 
the  profound  change  necessary  for  the  complete  success 
of  the  deceptive  resemblance.  The  deeply  rooted  instinct 
to  escape  when  alarmed  has  been  modified  into  a  stronger 
instinct  to  remain  motionless  at  all  costs  in  order  to 
maintain  the  appearance  of  a  dead  leaf,  for  the  slightest 
movement  would  attract  the  eye  of  an  enemy,  who  would 
certainly  investigate  the  object  more  closely  and  perhaps 
handle  it  roughly.  The  Mutationist  who  believes  that  this 
deceptive  appearance,  so  minutely  perfect,  was  produced 
more  or  less  complete  in  one  step,  will  have  to  admit 
that  the  sudden  modification  of  instinct,  by  a  strange 
coincidence,  took  place  at  the  same  time,  or  that  at  least 
it  occurred  in  connection  with  the  other.  The  Darwinian, 
on  the  other  hand,  believes  that  both  modifications  took 
place  by  equally  slow  gradations. 

Very  interesting  examples  of  special  procryptic  colour- 
ation are  the  resemblances  of  insects  to  bird  droppings 
on  leaves.  There  is  a  beautiful  example  in  England — 
the  little  moth  Cilix  glaucata  at  rest  fully  exposed  on  a 


<  M 


b  z 


H     V 


o  P 


RESEMBLANCE   TO  BIRD   DROPPINGS       199 

leaf.^  The  resemblance  may  be  either  to  a  dropping 
which,  fallen  from  a  height,  has  spread  out  to  form  a  white 
and  mottled  grey  patch  on  a  leaf,  or  to  one  which  has 
kept  its  cylindrical  shape,  and  appears  dark  grey  or 
grey-brown  and  white. 

The  young  caterpillars  of  Papilio  dardanus  much 
resemble  the  latter  object,  and  their  very  sluggish  habits 
contribute  considerably  towards  the  illusion. 

The  former  class  is  well  exemplified  by  a  beautiful 
Geometrid  moth  ^  which  rests  with  outspread  wings  fully 
exposed  on  the  surface  of  a  leaf.  The  wings  are  of  a  chalky 
white  hue,  with  wavy  darker  lines,  and  in  the  centre  of 
the  fore  wing  is  a  dark,  irregular  patch  of  black  and  brown, 
glistening  here  and  there  with  silver.  The  whole  produces 
an  effective  likeness,  which  must  be  seen  in  its  natural 
surroundings  to  be  believed.  If  the  moth  is  frightened 
it  flies  away,  but  takes  up  the  same  exposed  position  on 
another  leaf. 

A  propos  the  silver  marking,  it  is  curious  how  rare 
silver  is  on  insects  ;  gold  is  perhaps  commoner.  Besides 
the  above  case,  the  under  surfaces  of  Fritillary  and 
some  other  butterflies,  and  the  marks  on  some  Plusia 
moths,  I  have  only  seen  one  other  insect  with  silver — a 
large  Saturnid  caterpillar,  green,  with  humps  on  the 
back  covered  on  one  side  with  pure  silver.  The  attempt 
to  rear  this  beautiful  caterpillar  was  unsuccessful,  so  the 
name  cannot  be  given. 

Certain  insects  which  resemble  bark,  and  are  to  be 
found  on  tree  trunks,  are  very  wonderful  examples  of 
procrypsis,  though  whether  it  is  special  or  general  pro- 
crypsis  is  a  matter  of  words  only. 

Many  Lasiocampidae  have  caterpillars  which  are  seen 
with  difficulty  when  at  rest,  so  closely  do  they  lie  against 

1  First  recorded  by  Sidgwick  in  the  Journal  of  the  Rugby  School  Natural 
History  Society. 

^  Problepsis  cegretta. 


200  THE    COLOURATION  OF  INSECTS 

the  bark  which  they  resemble.  On  Damba  Isle  one  of 
my  natives  came  to  tell  me  he  had  found  some  caterpillars 
on  a  tree  trunk,  and  when  I  went  to  look  he  showed  me 
three  Lasiocampids,  lying  flat  on  the  bark  at  a  point 
where  its  surface  was  somewhat  irregular.  While  looking 
at  them  and  marvelling  at  the  minute  detail  of  the  resem- 
blance, I  gradually  became  aware  that  the  immediate 
surroundings  of  these  caterpillars  were  not  bark  but  more 
caterpillars,  and  much  to  the  native's  amazement,  nine 
of  them  were  found  lying  closely  packed  side  by  side,  and 
utterly  indistinguishable  from  the  bark  except  by  the 
very  closest  inspection.  These  caterpillars  fed  at  night 
only,^  crawling  up  the  trunk  when  the  sun  set  and 
returning  to  the  same  resting  place  next  day.  The 
perfection  of  the  concealment  owes  something  to  attitude. 
The  claspers  are  spread  out  sideways,  so  that  the  body 
lies  flat  against  the  bark.  The  surface  of  the  skin  is 
roughened  by  numerous  little  excrescences,  and  the  gap 
between  the  edge  of  the  body  and  the  bark  is  partly 
obliterated  by  fleshy  lappets,  and  often  by  short, 
soft  hairs. 2 

It  is  worth  pointing  out  that  a  very  large  insect  may 
be  concealed  in  a  way  that  c  nnot  be  believed,  unless 
it  is  actually  seen  in  its  natural  surroundings.  It  is  well 
known  that  the  caterpillar  of  the  Privet  Hawk  Moth, 
with  its  lilac  and  white  oblique  stripes,  is  not  so  conspicuous 

^  A  colony  of  Eupterotidae  caterpillars  (Chrysopsyche  varia)  was  found 
on  Bugalla  Islo  resting  by  day  on  a  tree  trunk.  Wishing  to  obtain  the 
perfect  moth  I  took  some  of  the  caterpillars  and  kept  them  in  a  large 
circular  glass  topped  box  in  which  they  rested  quietly  during  the  day. 
.When  evening  came  they  formed  the  usual  procession  and  atten>pted 
to  climb  upwards,  which  of  course  they  could  not  do.  The  result  was 
extremely  absurd,  for  the  caterpillars  formed  an  endless  chain,  nose  to 
tail  one  behind  another,  which  ceaselessly  promenaded  around  the  cir- 
cumference of  the  box  in  the  endeavour  to  find  a  path  upwards.  Although 
there  was  plenty  of  food  in  the  box  they  would  not  eat,  since  the  proper 
preliminary  of  marching  t/jo  the  tree  trunk  had  not  been  performed,  and 
I  had  to  put  the  caterpillars  back  on  the  tree  and  hope  to  secure  the 
cocoons  later.     The  limitations  of  instinct  are  here  well  shown. 

*  See  diagram  in  The  Colours  of  Animals,  p.  30. 


CONCEALMENT   OF  A  LARGE   INSECT      201 

as  would  be  expected  among  the  leaves  and  varying  lights 
on  a  bush, ^  but  the  following  is  a  more  remarkable  example. 
On  Kimmi  Islet  I  was  looking  at  a  bush  thinly  covered 
with  small  leaves,  and  thought  I  saw  a  small  brown 
"  micro  "  moth  sitting  on  one  of  the  leaves.  But  gradually 
it  became  obvious  that  what  I  was  looking  at  was  not  a 
small  moth,  but  part  of  the  ventral  aspect  of  an  enormous 
green  Saturnid  caterpillar,  which  was  on  the  lower  surface 
of  a  twig,  its  anterior  segments  being  at  an  angle  with 
the  twig,  as  in  the  common  attitude  of  many  large  cater- 
pillars, such  as  those  of  our  English  hawk-moths.  The 
closely  folded  brown  legs  on  the  first  three  segments  had 
made  the  brown  area  which,  against  the  green  of  the  rest 
of  the  caterpillar,  had  been  mistaken  for  a  small  moth 
sitting  on  a  leaf.  There  was  a  whitish-green  stripe  running 
along  the  mid-ventral  line  of  the  caterpillar,  which  must 
have  served  to  break  up  the  otherwise  uniform  green 
area,  and  helped  to  render  the  huge  form  difficult  to  be 
seen.  The  curious  point  was  that  when  the  insect  had 
once  been  visualized,  I  could  not  un-see  it  again,  and  found 
great  difficulty  in  realizing  how  I  had  at  first  failed  to 
discern  it.  Some  of  the  natives  were  called  up  and  asked 
if  they  saw  anything  on  the  bush,  and  their  surprise  was 
as  great  as  mine  when  I  pointed  out  the  caterpillar.  The 
moth  was  reared,  and  proved  to  be  Bunaea  phaedusa. 

When  procryptic  colouring  is  dealt  with,  place  must 
be  found  for  mention  of  Seasonal  Variation.  Certain 
butterflies  have  been  known  for  some  years  to  have 
appearances  differing  greatly  in  the  wet  and  dry  seasons. 
So  marked  are  the  differences  in  the  Nymphaline  genus 
Precis,  for  example,  that  two  forms  of  P.  sesamus,  one 
salmon-pink  above,  the  other  deep  blue,  with  extreme 
difference  of  pattern  and  colour  on  the  under  surfaces, 
were  thought  to  be  distinct  species  until  G.  A.  K.  Marshall 
bred  one  from  eggs  laid  by  the  other.  ^ 

^  The  Colours  of  Animals,  p.  42. 

'  Trans.  Ent.  Sac,  1902,  part  iii,  p.  414  et  seq. 


202  THE  COLOURATION  OF  INSECTS 

Poulton,  from  careful  study  of  this  genus,  concluded 
that  "  dry  "  forms  are  more  procryptic,  and  that  this 
is  due  to  the  operation  of  Natural  Selection  during  the 
greater  stress  of  the  dry  season,  when  insects  are  so  scarce 
that  insectivorous  animals  need  to  work  harder  to  obtain 
food,  and  the  risk  to  any  particular  insect  is  proportionately 
greater.!  Now  the  climate  of  the  islands  of  Lake  Victoria 
has  been  shown  to  be  more  uniform  than  that  of  the  main- 
land, ^  and  it  is  very  interesting  and  significant  that  in 
the  case  of  the  commonest  Precis  there  (P.  archesia),  the 
only  form  met  with  was  the  "  wet  "  one  ;  and  of  P.  sesamus, 
the  salmon-pink  "  wet  "  form  was  so  much  the  commonest 
that  the  appearance  of  a  "  dry  "  one  was  quite  a  memorable 
event.  During  the  campaign  in  German  East  Africa,  I 
first  became  familiar  with  the  phenomena  of  a  typical 
dry  season,  and  was  soon  impressed  by  the  much  greater 
procrypsis  of  the  "  dry  "  Precis,  and  also  of  such  Pierines 
as  Teracolus,  Belenois,  Pinacopteryx.  When  the  grass  is 
quite  dead  and  dried  up  it  becomes  brown,  tinted  with 
pink  or  grey,  and  the  dry  season  Pierines,  when  at  rest, 
harmonize  most  admirably  with  their  surroundings  on 
account  of  the  suffusion  of  the  under  surface  with  brown, 
grey  or  pinkish  scales,  so  that  they  are  often  exceedingly 
difficult  to  detect  after  they  have  alighted.  It  is  note- 
worthy that,  just  as  in  the  case  of  the  moth  above  men- 
tioned, this  especially  procryptic  colouring  is  only  found 
wher*^  it  is  needed  on  the  under  surface,  viz.  on  the  whole 
-of  the  hind  wing,  but  only  on  the  tip  of  the  fore  wing, 
which  is  not  covered  by  the  hind  wing  in  the  position 
of  complete  rest.  The  remainder  of  the  under  surface 
of  the  fore  wing  is  as  in  the  "  wet  "  form. 

The  above  examples  of  conceaUng  colouration  are  all 
procryptic  ;  that  is  to  say,  they  are  species,  found  highly 
desirable   by   vertebrate   enemies,    which    have    acquired 

1  Trans.  Ent.  Soc,   1902,  part  iii,  pp.  424-443. 

2  See  chart.  Chapter  iii. 


ANTICRYPSIS  208 

colours,  shape  and  habits  concealing  them  from  dis- 
covery by  enemies. 

The  class  of  anticryptic  colouration  has  not  so  many 
examples.  In  it  are  to  be  found  creatures  whose  con- 
cealment aids  them,  primarily,  not  to  escape  their  enemies 
but  to  obtain  their  prey. 

On  many  occasions  I  have  seen  a  butterfly  apparently 
caught  by  a  flower  which  it  had  visited,  and  at  first  imagined 
that  the  proboscis  had  become  entangled.  On  examining 
the  flower  it  was  found  that  the  butterfly  had  been  caught 
by  a  spider,  which  had  lain  in  wait  on  a  flower  which  it 
so  closely  resembled  that,  until  one  had  had  this  experience 
several  times,  one  still  imagined  it  was  part  of  the  flower. 

Two  species,  or  possibly  two  forms  of  the  same  species, 
have  been  frequently  met  with  that  thus  caught  their 
prey,  both  of  the  "  crab-spider  "  type.  One  was  found 
on  a  yellow  flower  like  a  small  sunflower,  the  other  was 
on  a  milk-white  flower  of  a  small  low-growing  herb.  In 
each  case  the  spider  was  of  precisely  the  same  tint  as  the 
flower  on  which  it  caught  its  prey. 

The  curious  and  interesting  Mantidae  are  often  quoted 
as  instances  of  anticrypsis.  A  species  Pseudocreobotra 
ocellata  was  abundant  on  the  islands,  and,  like  the  spider, 
varied  in  hue  according  to  the  colour  of  the  flowers  which 
it  frequented  in  order  to  catch  its  prey.  One  form,  green 
and  yellow,  was  found  on  the  small  "  sunflower,"  the  other, 
green  and  mauve,  sat  among  the  spikes  of  purple  flowers 
of  an  abundant  aromatic  labiate  herb.  Very  young  speci- 
mens found  on  the  latter  were  of  a  uniform  purple  or 
mauve  tint,  and  it  was  extremely  difficult  to  see  them. 

In  aU  these  cases,  however,  the  ^rocryptic  element 
cannot  be  definitely  set  aside,  since  birds  are  well  known 
to  eat  spiders,  and  Mantidae  are  so  universally  cryptic 
that  they  must  be  supposed  to  be  highly  edible. ^ 

1  In  1916-17  I  had  a  tame  Cercopithecus  monkey  which,  taken  out 
to  himt  for  itself,  would  devour  Mantidae  with  the  utmost  avidity. 


204  THE  COLOURATION  OF  INSECTS 

But  the  foUomng  example  i.s  more  probably  anticryptic. 

On  Nsadzi  Isle  there  is  a  fine  sandy  beach  frequented 
by  Egyptian  geese  and  wading  birds,  whose  droppings 
attract  little  blue  butterflies  and  Skippers,  which  settle 
on  them  to  feed.  I  found  one  day,  sitting  on  a  patch 
of  bird  dropjDing  and  sucking  the  juices  of  a  captured 
Lycaenid  butterfly,  a  small  flat  bug,  Mononyx  grandicollis, 
of  the  group  Cryptocerata,  whose  tints  accorded  admirably 
with  those  of  the  dropping  on  the  wet  sand. 

Hitherto  we  have  been  considering  examples  of  insects 
concealed  by  their  resemblance  to  their  surroundings. 
But  a  large  number  of  species  are  extremely  conspicuous, 
and  many  of  them  seem  to  court  attention,  I  use  these 
words  dehberately,  and  as  a  result  of  several  years'  obser- 
vation in  the  field.  But  a  school  has  arisen  in  America 
following  the  teaching  of  the  distinguished  artist-naturaHst 
Thayer,!  which  believes  that  all  creatures  are  concealed 
by  their  resemblance  to  their  surroundings,  no  matter 
how  brilliant  and  startling  their  colouration  appears  to 
be  in  the  cabinet.  Many  butterflies  are  supposed  to  be 
like  the  flowery  part  of  their  surroundings. ^  In  some 
cases  this  is  certainly  true  ;  the  greenish-yellow  Pierines 
of  genus  Terias,  when  feeding  from  yellow  flowers  among 
herbage,  are  very  well  in  harmony  with  them,  and  quite 
well  concealed.  So  also  the  under  surfaces  of  the  wings 
of  other  Pierines  tone  very  well  mth  flowers  or  grasses  ; 
our  own  orange-tip  is  a  well  known  instance. 

But  these  are  all  what  a  Darwinian  calls  procryptic, 
so  that  here  there  is  no  difference  between  him  and  the 
follower  of  Thayer.  When  the  species  which  Poulton 
called  Aposematic  (i.e.  with  "  warning  "  colouration)  are 
considered,  it  is  difficult  to  accept  the  doctrine  that  they 
really  harmonize  with  their  environment  or  with  any  part 
of  it.     Take  for  example  the  typical  habitat  on  the  islands 

*  See    Concealing   Coloration   in   the    A7%imal   Kingdom. 
2  Loc.  cit.,  pp.  228-229.     New  edition,  1918. 


THAYER'S   VIEWS  205 

of  a  typically  aposematic  butterfly,  Acraea  egina.  This 
brilliant  black  and  scaiMet  species  could  be  seen  in  great 
numbers  on  the  open  grass  land  near  the  well  defined  border 
of  the  dense  forest  which,  as  has  been  described,  ends 
abruptly,  presenting  a  dense  wall  of  greenery  among  ' 
which  one  searches  in  vain  for  scarlet  flowers  or  any  patch 
of  scarlet  with  which  the  Acraea  could  harmonize.  Near 
the  edge  of  the  forest,  but  often  as  much  as  a  hundred 
yards  away,  in  the  open  grass  land,  flourish  clumps  of 
the  plant  Erlangea  tomentosa,  which  bears  fine  heads 
of  lavender  coloured  flowers.  These  are  extraordinarily 
attractive  to  Acrasines,  which  crowd  together  on  them, 
making  a  brilliant  picture.  Not  only  the  black  and 
scarlet  Acraea,  such  as  egina,  zetes,  perenna  and  the 
rarer  pJiarsalus,  together  with  smaller  species  similarly 
coloured,  but  black  and  white  females  of  Planema  macarista, 
P.  alcinoe  and  P.  aganice,  the  brown  males  of  the  two 
latter,  and  black,  orange  and  white  males  of  P.  macarista, 
with  both  sexes  of  the  similarly  coloured  P.  poggei,  all 
congregate  in  various  proportions,  and  being  freely  exposed 
on  the  lavender  heads  of  flower,  make  a  very  brilliant 
and  conspicuous  assembly  which  by  no  stretch  of  imagin- 
ation could  be  considered  to  harmonize  with  the  surround- 
ings. 

It  is  true  that  one  tree  with  brilliant  scarlet  flowers, 
known  to  the  Baganda  as  "  Ekirikiti "  {Erytkrina  tomentosa), 
is  plentiful  on  the  islands,  but  butterflies  do  not  visit 
it,  and  it  usually  has  no  leaves  at  the  time  of  its  flowering, 
so  that  the  isolated  bunches  of  flowers  high  up  in  the  air 
can  hardly  be  considered  to  form  a  background  against 
which  scarlet  butterflies  would  be  invisible.  Moreover, 
the  tree  usually  stands  by  itself  in  open  places. 

It  must,  I  think,  be  admitted  that  such  insects  as  the 
above  are  conspicuous  in  their  natural  surroundings,  and 
the  explanation,  first  suggested  by  Bates,  is  that  these 
are  relatively  distasteful  species,  to  whose  advantage  it 


206  THE   COLOURATION   OF  INSECTS 

is  that  they  should  be  as  conspicuous  as  possible  in  order 
that  their  vertebrate  enemies  may  readily  recognize  them 
as  things  to  be  avoided.  The  colours  of  such  creatures 
are  therefore  known,  in  the  terminology  used  by  Poulton,^ 
as  "  warning  colours  "  or  "  aposemes." 

Obviously  it  will  be  to  the  advantage  of  such  insects 
that  their  aposemes  should  be  of  simple  type  to  aid  recog- 
nition and  memory  on  the  part  of  the  enemy.  Hence 
one  finds  schemes  such  as  black  and  yellow  alternating 
rings  in  a  wasp,  or,  in  a  butterfly,  the  wings  of  one  colour 
except  for  strongly  contrasted  patches  of  another  colour, 
especially  at  the  apex  of  the  fore  wing.  It  is  an  interesting 
point  that  this  apical  or  sub -apical  patch  of  contrasting 
colour  usually  has  its  long  axis  at  right  angles  to  the  long 
axis  of  the  wing.  Presumably  the  transverse  direction 
makes  the  patch  more  conspicuous  during  the  movements 
of  the  wing  than  if  it  were  parallel  to  the  long  axis  of  the 
wing.  This  point  is  well  shown  in  the  illustrations  of 
the  various  Planema  (see  Plates). 

Before  dealing  with  typically  aposematic  species,  it 
may  be  said  that  quite  a  number  of  procryptic  insects 
are  furnished  with  an  aposeme  which  they  display  if 
an  inquiring  enemy  comes  unpleasantly  near.  The 
caterpillars  of  Lasiocampidae,  previously  alluded  to, 
show,  if  disturbed,  a  cleft  across  the  second  or  third 
segments,  or  both,  filled  with  brightly  coloured  fine 
sharp  spines,  which  very  readily  become  detached 
and  penetrate  one's  skin,  and  would  prove  very  un- 
pleasant in  the  mouth  of  an  enemy  tasting  such  a 
caterpillar  for  the  first  time.  The  colour  of  the  spines 
varies  in  different  species.  It  may  be  orange,  or  pink, 
or  steely  blue-black,  but  is  always  such  as  to  make  the 
spines  very  conspicuous.  When  the  caterpillar  is  quietly 
at  rest  and  concealed  by  its  procrypsis,  the  cleft  is  closed, 
but  if  the  caterpillar  is  disturbed  or  touched  it  makes 

1  The  Colours  of  Animals,  pp.  336-337. 


BLACK    AND    WHITE   AI'OSEMATIC   CATERPILLARS   OF   THE    LARGE    NOCTUIU 
MOTH   AMBLYPRORA    MAGNIFICA. 


PROCRYPSIS  COMBINED  WITH  AN  APOSEME  207 

the  cleft  gape  widely  open,  so  that  the  brightly  coloured 
spines  are  fully  displayed.  This  may  be  seen  in  England 
in  the  caterpillar  of  the  "  Lappet  "  moth. 

In  the  case  of  these  caterpillars  it  must  be  remembered 
that  the  presence  of  such  an  aposeme  does  not  necessarily 
imply  that  the  caterpillar  is  intrinsically  distasteful,  but 
that  it  possesses  some  unpleasant  quality  on  account  of 
which  it  had  better  be  left  alone.  I  have  a  certain  amount 
of  evidence  that  Hymenoptera,  such  as  the  stinging  ants, 
bees  and  wasps,  are  not  avoided  so  much  on  account  of 
inedibility  as  on  account  of  their  powers  of  defence,  which 
they  advertise  by  their  conspicuous  scheme  of  colouring, 
or  their  habits. 

So  that  the  combination  of  procrypsis  with  an  aposeme 
is  not  so  inconsistent  with  the  theory  of  natural  selection 
as  it  might  appear  to  be  at  first.  Another  interesting 
example  of  this  combination  is  a  fine  large  Noctuid  moth, 
abundant  on  the  islands  (Ophideres).  It  was  usually  first 
seen  on  the  wing  after  it  had  been  disturbed  from  its 
resting  place,  when  its  orange  hind  wings  bordered  with 
black  were  very  conspicuous.  If  it  was  followed  up  it 
was  seen  to  settle  head  downwards  on  the  bark  of  a  tree, 
expose  fully  for  a  moment  its  orange  hind  wings,  and  then 
suddenly  close  the  wings  with  a  snap  and  become  invisible 
owing  to  the  mottled  grey-green  and  brown  tints  of  the 
fore  wings  closely  resembling  the  surface  of  the  bark. 
I  am  inclined  to  think  that  the  conspicuous  hind  wings 
are  aposematic,  else  why  should  the  moth  take  such  pains 
to  display  them  for  a  moment,  on  alighting,  before  covering 
them  with  the  procryptic  fore  wings  ?  I  suggest  that  the 
moth  endeavours  to  dissuade  a  pursuing  enemy  by  freely 
displaying  its  warning  colours,  and  then  settles  and  be- 
comes invisible  to  any  new  enemy  that  had  not  seen  it 
when  on  the  wing. 

On  the  other  hand,  it  is  possible  that  the  colour  of  the 
hind  wings  is  of  the  nature  of  directive  markings,^  which 
*  Colours  of  Anhnals,  p.  204  et  seq. 


208  THE   COLOURATION  OF  INSECTS 

entice  the  enemy  to  seize  an  insect  at  some  particular 
part  which  is  especially  brittle,  and,  being  seized,  breaks 
away,  so  that  the  insect  escapes  unharmed  save  for  the 
wholly  immaterial  loss  of  some  part  of  the  wing.  Such 
special  directive  marks  often  take  the  form  of  conspicuous 
eye-like  spots  at  the  angle  of  the  hind  wing  or  along  its 
margin,  or  of  tails,  and  every  collector  must  have  noticed 
how  often  in  Papilio,  Charaxes,  Satyrinae,  Lycaenidae  such 
parts  are  missing,  and  a  gap  in  the  margin  of  the  hind 
wing  shows  where  the  enemy  has  secured  nothing  but  a 
mouthful  of  dry  wing  tissue.  These  gaps  in  the  wing 
are  just  in  the  position  where  the  wings  are  least  likely 
to  be  damaged  by  contact  with  objects  during  flight. 
Moreover,  it  is  just  these  pieces  of  the  wing  which  break 
off  when  the  butterfly  is  vigorously  fluttering  in  the  folds 
of  a  net ;  the  tails  of  Papilionidae  are  notorious  in  this 
respect. 

On  one  minute  islet  that  I  visited  there  were  numbers 
of  black  and  white  wagtails,  and  little  Lycaenid  butterflies 
were  plentiful.  It  was  noticed  that  a  large  proportion 
had  a  A-shaped  piece  missing  from  both  hind  wings 
symmetrically  as  if  a  wagtail  had  seized  the  butterfly 
by  the  hind  wings  when  it  was  at  rest,  and  the  butterfly 
had  escaped  owing  to  that  portion  of  the  wing  breaking 
away.  After  leaving  the  islands  in  1915  I  was  fortunate 
enough  to  see  this  actually  happen,  and  also  to  see 
numbers  of  Lycaenidae  actually  eaten  by  wagtails.^  The 
question  of  directive  markings  has  been  here  dealt  with 
because  it  seems  possible  that  certain  instances  of  very 
simple,  conspicuous  patches  of  colour,  which  in  the  dead 
specimen  look  like  aposemes,  are  possibly  directive  mark- 
ings, I  refer  especially  to  the  orange,  crimson,  or  purple 
tips  of  the  fore  wings  of  the  Pierine  genus  Teracolus. 
These  lovely  butterflies  are  conspicuous  on  the  wing,  but 
shy  and  wary.     When  one  is  fluttering  in  the  net  the 

1  Vide  p.  238 


BEHAVIOUR  OF  APOSEMATIC  SPECIES    209 

orange  tips  very  frequently  are  broken,  which  is  an  un- 
usual occurrence  with  butterflies,  the  anterior  part  of  the 
wing  usually  being  the  strongest  (c/.  supra).  As  has 
been  said,  the  lower  surfaces  of  these  butterflies  are  de- 
cidedly procryptic,  but  it  must  be  acknowledged  that, 
as  in  our  English  "  orange-tip,"  the  bright  colours  of 
the  Teracolus  are  more  developed  in  the  male,  so  that 
sexual  selection  may  have  been  a  factor  in  producing 
them  {vide  infra). 

We  must  return  to  the  subject  of  aposemes,  having 
digressed  somewhat. 

Just  as  cryptic  insects  must  behave  in  accordance  with 
the  resemblance  to  their  surroundings,  so  aposematic 
species  have  a  behaviour  in  keeping  with  their  colouring. 
It  would  be  of  Uttle  use  for  a  gaudy,  distasteful  insect 
to  retreat  timidly  or  endeavour  to  hide  itself  on  approach 
of  an  enemy  which,  only  partially  seeing  it,  might  grab 
at  it  and  damage  it  fatally  before  the  mistake  was  found 
out.  Everything  is  to  be  gained  by  flaunting  the  banner 
in  the  face  of  the  enemy,  so  that  there  can  be  no  possibility 
of  a  mistake.  Consequently,  aposematic  insects  are  of  the 
boldest  demeanour,  and  are  the  species  most  frequently 
seen  by  the  casual  observer.  If  endeavours  are  made 
to  catch  one,  for  instance  a  Planema  butterfly,  it  merely 
flits  out  of  reach,  and  returns  to  the  same  spot  apparently 
unalarmed. 

A  large  grasshopper  {Dictyophora  laticincta),  of  family 
Acrididae,  was  frequently  met  with  on  the  islands  fully 
exposed  on  pathways  :  a  bloated  creature  with  heavy 
body,  whose  wings  are  so  atrophied  that  it  cannot  possibly 
fly.  So  sluggish  is  it  that  it  scarcely  troubles  to  move 
out  of  the  way,  or  gives  a  feeble  hop  merely  carrying  it 
for  a  distance  about  equal  to  the  length  of  its  own  body. 
In  colour  it  is  grey-black,  and  the  short  wings  are  scarlet, 
and  there  is  some  of  the  same  colour  along  the  sides  of 
the  fat  abdomen.     If  persistently  annoyed  it  will  raise 

15 


210  THE  COLOURATION  OF  INSECTS 

the  wing  covers  to  show  the  red  wings  underneath.  Such 
an  insect,  a  priori,  must  be  distasteful,  and  proved  to  be 
so  when  offered  to  my  young  monkey,  who  would  eat 
greedily  until  he  was  sick  equally  large,  but  procryptic, 
grasshoppers. 

Since  I  offered  this  grasshopper  to  Wee  Man  he  naturally 
thought  it  would  be  edible,  and  at  once  seized  it,  though 
he  did  not  straightway  bite  it  as  he  would  have  done 
had  it  been  the  ordinary  procryptic  species  he  was  accus- 
tomed to  eat.  While  he  held.it  in  his  hand  the  grasshopper 
emitted  copious  bubbles  of  strongly  smelling  yellow  froth 
from  the  thoracic  spiracles,  forcing  it  out  by  first  dis- 
tending and  then  strongly  contracting  the  abdomen,  so 
that  a  hissing  sound  was  produced,  audible  several  yards 
away.  At  the  same  time  the  wing  covers  were  raised 
so  as  to  display  the  bright  red,  black  bordered  wings. 

Wee  Man  was  obviously  much  interested  in  this  very 
curious  and,  to  him,  novel  phenomenon,  and  tasted  the 
froth,  but  though  he  obviously  did  not  like  it,  he  persisted 
in  trying  to  eat  the  insect,  pulling  it  to  pieces  and  tasting 
each.     But  none  of  it  was  actually  eaten  ! 

Many  other  insects,  none  of  which  are  procryptic,  emit 
strongly  smelling,  bright  coloured  fluid  when  roughly 
handled.  This  is  well  known  to  all  who  have  collected 
Acraeine  butterflies. 

The  following  is  quoted  from  my  article  in  Bedrock  ^  : 

*'  A  most  typically  aposematic  Arctiid  moth  {Bhodo- 
gastria  leucoptera)  was  found  resting  fully  exposed  on  low 
herbage.  Its  wings  were  of  a  pure  hard  shining  white, 
but  not  very  thickly  scaled,  so  that  when  they  were  brought 
together  over  the  body  of  the  moth,  the  abdomen,  which 
was  of  a  bright  rose  pink,  was  distinctly  visible.  The 
thorax  was  pure  white,  spotted  with  black.  The  legs 
were  of  the  same  bright  rose  as  the  abdomen.  When 
the  moth  was  disturbed  it  separated  its  wings  and  spread 

'  Vol.  ii,  1913,  "Notes  on  the  Struggle  for  Existence  in  Tropical  Africa." 


BEHAVIOUR  OY  APOSEMATIC   SPECIES    211 

out  the  legs  so  as  to  display  the  bright  pink  (a  typical 
aposeme),  and  emitted  from  the  thorax  just  behind  the 
head  a  copious  yellow  froth,  till  a  mass  of  yellow  bubbles, 
with  a  very  strong  acrid  odour  and  taste,  projected  on 
each  side." 

Equally  remarkable  is  another  specialized  grasshopper, 
known  to  the  Baganda  as  "  Semukutu."  ^  It  is  a  large 
heavy  insect  of  dull  greenish-grey  colour,  and  though 
not  in  any  way  aposematic  in  colouration,  yet  has  all 
the  characteristics  of  such  an  insect.  It  has  no  trace 
of  wings  or  wing  covers,  and  the  thorax  is  set  with  spines 
around  its  margin.  The  abdomen  is  fat  and  bloated, 
and  the  sluggish  insect  makes  no  attempt  to  evade  an 
approaching  enemy.  I  could  never  induce  a  monkey  to 
tackle  one  of  them.  When  handled,  a  Semukutu  ejects 
with  some  force  from  the  sides  of  the  thorax  a  yellow 
fluid  of  strongly  acrid  odour,  which  would  prove  extremely 
unpleasant  in  the  mouth  ;  and,  indeed,  the  Baganda  will 
not  even  handle  the  insect,  for  they  say  the  fluid  produces 
sores  on  the  skin.^  But  I  never  found  that  it  had  any 
effect  on  my  skin,  and  I  have  handled  a  great  many 
Semukutu.  This  is  an  interesting  case,  for  here  we  have 
an  insect  which  has  acquired  the  habits  and  attributes 
of  an  aposematic  species,  yet  not  the  colouration.  Indeed, 
a  young  specimen  is  rather  procryptic,  being  mottled  with 
green,  but  it  has  not  then  the  power  of  exuding  the 
acrid  fluid.  One  might,  however,  suggest  that  the  appear- 
ance of  this  stout,  spiny,  wingless  grasshopper  is  so  unlike 
that  of  others  that  it  can  be  very  easily  recognized,  and 
the  need  for  aposematic  colours  may  not  have  arisen. 

The  above  observations  on  the  monkey  and  grasshoppers 
have  exemplified  the  deliberate  use  of  an  aposeme  by  an 
insect  when  hard  pressed.  This  is  again  brought  out 
very  well  by  an  experiment  with  fowls,  the  subject  being 

^  Enyaliopsis,  possibly  durandi. 

*  See  Bulletin  of  the  Entomological  Research  Committee,  vol.  i,  p.  227, 


212  THE  COLOURATION  OF  INSECTS 

Phymateus  viridipes,  another  large  grasshopper  of  a  hard 
green  colour,  with  spiny  thorax,  and  fully  developed  blue 
and  crimson  wings,  so  that  when  flying  it  is  extremely 
conspicuous. 

One  of  these  was  put  on  the  ground  some  little  distance 
away  rom  a  group  of  fowls,  one  of  which  at  once  ran 
up  to  it.  The  grasshopper  remained  where  it  was,  but, 
when  the  fowl  came  dangerously  near,  raised  the  wings 
and  wing  covers  perpendicularly  and  opened  out  the 
former  to  show  their  bright  red  colouring.  The  fowl 
halted,  looked  at  it,  turned  round  and  walked  away, 
nor  could  it  be  induced  to  touch  the  insect.  After  a 
similar  result  had  been  obtained  on  another  occasion, 
the  grasshopper  was  killed  and  laid  down  near  the  fowls, 
.^ho  wings  being  of  course  hidden  beneath  the  covers. 
A  half-grown  fowl  at  once  ran  up  and  pecked  at  it,  and, 
being  pursued  by  another,  ran  off  with  the  grasshopper, 
put  it  down  and  pecked  at  it  again,  but  certainly  did 
not  seem  to  relish  it,  finding  it  very  tough.  The  fowl  at 
length  picked  off  the  legs,  but  made  no  impression  on  the 
body. 

Just  as  it  was  about  to  leave  it,  a  second  half-grown 
fowl  rushed  up,  took  it  away  and  pecked  vigorously  at 
it,  pulled  off  the  head  but  did  not  eat  it,  and  finally 
walked  away  and  left  it.  These  observations  show, 
firstly,  the  value  of  the  aposeme  in  warning  off  dangerous 
enemies,  and  secondly,  the  distastefulness  of  the  owner. 

It  will  have  been  noted  that  the  fowl  made  no  impression 
on  the  tough  body  of  the  grasshopper,  and  this  brings 
out  another  point.  Should  an  aposematic  insect  have 
the  misfortune  to  be  one  of  those  that  are  tasted  by  an 
inexperienced  young  foe,  it  may  quite  possibly  survive 
the  tasting,  and  be  able  to  propagate  its  kind  if  it  is  of 
sufficient  toughness.  Consequently  one  finds  that  apose- 
matic species,  in  strong  contrast  to  procryptic  species, 
are  endowed  with  astonishing  powers  of  resisting  injury, 


HAIRY  CATERPILLARS  213 

at  any  rate  in  the  case  of  Lepidoptera.  It  is  quite  impos- 
sible to  kill  a  Danaine  or  Acraeine  butterfly  by  the  mild 
pinch  on  the  thorax  sufficient  for  a  non-aposematic  Pierine 
or  Satyrine,  for  their  tissues  are  so  elastic  that  but  little 
impression  is  made  on  them.  Further,  such  insects  have 
remarkable  powers  of  resistance  to  chemical  poisons.^ 
It  takes  a  very  long  time  to  kill  an  Acraea,  or  a  Burnet 
moth,  in  a  cyanide  bottle,  and  I  have  had  Planema  pupae 
all  night  in  a  killing  bottle,  which  when  taken  out  in  the 
morning  were  unharmed,  and  showed  their  characteristic 
movements,  although  that  very  bottle  was  in  daily  use 
for  other  insects,  which  very  quickly  succumbed. 

It  has  been  pointed  out  above  that  a  disagreeable  taste 
or  smell  is  not  the  only  quality  associated  with  aposemes, 
as  in  the  case  of  the  sting  of  a  wasp.  The  well  known 
irritating  qualities  of  fine  hairs  from  Arctiid,  Lymantrid, 
or  Lasiocampid  caterpillars,  or  the  spines  of  Apodid  or 
Saturnid  caterpillars  are  all  found  to  be  associated  with 
typically  aposematic  colouration.  In  this  case  the  aposeme 
has  no  bearing  on  the  actual  taste  of  the  insect,  but  only 
refers  to  the  presence  of  some  irritant  or  penetrating 
hairs  ;  indeed,  many  such  caterpillars,  as  in  Lymantridae, 
become  typically  procryptic,  and  presumably  edible  moths. 
But  the  rule  cannot  be  stated  that  when  the  aposeme  is 
due  to  adventitious  hairs,  etc.,  the  insect  is  not  distasteful 
in  itself,  for  many  Arctiid  caterpillars  renowned  for  their 
hairiness,  such  as  the  "  Woolly  Bear,"  become  typically 
aposematic  moths,  such  as  our  English  "  Tiger-moth." 
It  would,  however,  be  very  interesting  to  test  the  edibility 
of  Lymantrid  and  Arctiid  pupae  removed  from  the  hairy 
cocoon.  On  the  other  hand,  when  a  caterpillar  has 
aposemes  that  are,  as  it  were,  intrinsic,  that  is,  not  de- 
pending upon  hairs  or  spines,  it  seems  to  be  the  rule    hat 

^  It  must  be  acknowledged,  however,  that  certain  very  procryptic 
weevils,  found  on  the  ground  which  they  closely  resemble,  have  equal 
powers  of  resistance  to  chemical  poisons,  but  they  are  exceptional  in 
this  respect  among  procryptic  species. 


214  THE  COLOURATION   OF   INSECTS 

its  distasteful  qualities  are  carried  through  all  stages 
to  the  perfect  insect.  I  do  not  know  of  a  case  of  an 
aposematic  larva  of  this  type  becoming  a  procryptic, 
and  therefore  edible,  adult.  A  most  typical  instance  is 
the  Hypsid  moth,  pactolicus,  which  is  equally  conspicuous 
in  all  its  stages.  The  caterpillar  is  ringed  alternately 
with  dead  black  and  pure  Chinese  white,  the  head  being 
crimson.  It  feeds  fully  exposed  on  a  yellow  flowered 
vetch,  1  on  which  it  is  visible  from  far  away.  When  full 
fed  it  stretches  a  few  silk  threads  across  and  across  to 
make  an  open  hammock,  in  which  it  becomes  an  equally 
conspicuous  chrysalis,  fully  exposing  its  light  yellow 
colouring  with  black  markings.  The  large  adult  moth 
is  bright  orange  with  steely  blue-black  blotches,  and  is 
one  of  the  most  conspicuous  insects  ;  it  is  of  sluggish 
habit,  and  rests  freely  exposed  on  low  herbage,  or  flies 
slowly  and  heavily.  The  moths  of  this  family  are  some- 
times copied  by  other  less  favoured  insects,  and  there  is 
little  doubt  that  they  are  relatively  distasteful. 

On  the  other  hand,  cases  of  a  procryptic  caterpillar 
becoming  an  aposematic  adult  must,  I  think,  be  exceptional. 
I  have  not  yet  met  with  one  on  the  islands. 

A  very  interesting  species  is  the  typically  aposematic 
genus  Aletis.  These  moths  are  sometimes  mimicked  by 
butterflies  (see  p.  233).  One  species,  A.  erici,  was  found 
in  abundance  on  Sanga  Island  in  such  numbers  that  the 
bushes  had  been  completely  stripped  of  their  leaves 
(see  p.  103).  The  caterpillar  was  tawny  orange  with  black 
blotches,  and  was  extremely  conspicuous ;  since  many 
grouped  themselves  together,  hanging  head  downwards  in 
clusters  from  the  bare  twigs,  their  attitudes  accentuated 
the  conspicuous  colouring — they  had  the  typical  shape 
of  all  Geometridae.  Inasmuch  as  the  vast  majority  of 
Geometrid  larvae  are  procryptic,  the  ancestral  forms  were 
probably  so,  and  the  Aletis  has  been  transformed  from  a 
^  Crotalaria  striata. 


APOSEMATIC  INSECTS   CROWD  TOGETHER  215 

procryptic  to  an  aposematic  type,  the  larvae  still  retaining 
the  characteristic  shape  and  the  attitude  which  follows 
from  the  absence  of  the  first  three  pairs  of  claspers,  but 
acquiring  the  habit,  most  unusual  among  Geometrid  larvae, 
of  grouping  themselves  so  that  the  effect  of  the  warning 
colours  is  accentuated — a  habit  not  at  all  uncommon 
among  aposematic  insects. 

The  Peyitatomidae,  highly  odoriierous  Hemiptera,  resplend- 
ent in  green  or  blue  and  gold,  commonly  mass  together. 
In  1917  I  met  with  a  very  marked  instance  of  this 
aggregation.  An  Acridian  grasshopper,  ^  conspicuously 
coloured  green,  orange  and  black,  and  of  typically  apose- 
matic habits,  was  proved  very  definitely  to  be  distasteful 
to  a  young  monkey.  When  very  young  it  is  coal  black, 
speckled  with  yellow,  and  on  several  occasions  large 
numbers  were  found  closely  crowded  together  to  form  a 
black  mass  at  the  end  of  a  spray  of  herbage,  which  attracted 
my  attention,  whereas  a  single  individual  from  its  small 
size  would  easily  have  escaped  notice.  Some  of  these 
black  youngsters  were  given  to  a  monkey,  who  would 
not  even  taste  them,  although  hungry,  as  was  proved 
by  his  subsequently  eating  other  insects.  Although  the 
habit  of  collecting  in  a  mass,  whereby  the  conspicuousness 
'of  an  individual  is  much  exaggerated,  is  most  commonly 
made  use  of  for  aposematic  purposes,  yet  I  have  met 
with  an  instance  where  a  full  effect  of  procrypsis  was 
only  produced  when  a  number  of  individuals  collected 
together  in  a  certain  way.  The  effect  produced  was  a 
likeness  to  a  bird-dropping  on  a  leaf,  and  could  not  so 
well  have  been  produced  by  a  single  individual. 

The  species  concerned  is  the  Bombycid  moth,  Trilocha 
obliquissima,  of  which  the  type  specimen,  from  Angola, 
was  the  only  one  in  the  British  Museum  collection.  A 
company  of  very  young  caterpillars  was  found  on  Bugalla 
Island  on  a  leaf  of  a  Sapotaceous  tree,   Chrysophyllum. 

^  Zonocerus  elegans. 


216  THE  COLOURATION  OF  INSECTS 

The  general  colouration  was  a  mottled  stony  grey.  After 
the  first  moult  the  lighter  parts  of  the  markings  became 
chalky  white,  and  as  the  caterpillars  always  lay  close 
together  in  a  mass,  and  fed  on  the  flat  surface  of  the 
leaf  from  the  upper  parenchyma  only,  the  resemblance 
to  a  bird  dropping  was  very  close.  At  the  next  moult 
the  caterpillars  became  darker,  and  as  they  grew  larger, 
after  the  third  moult,  were  of  a  rich  brown.  They  now 
had  different  habits,  feeding  from  the  edge  of  the  leaf 
in  the  manner  of  all  large  caterpillars,  and  no  longer 
massing  together. 

When  full  grown  they  were  extraordinarily  procryptic, 
being  of  the  same  rich  brown  as  the  leaf  stalks,  with  green- 
ish and  purpUsh  mottlings,  the  body  being  swollen  here 
and  there  with  numerous  scale-like  excrescences  accurately 
resembling  scales  at  the  bases  of  the  leaf  stalks,  and 
rugosities  of  the  bark.  The  caudal  horn,  projecting 
forward  over  the  back,  also  helped  in  this  likeness.  The 
caterpillars  now  rested  along  twigs  and  leaf  stalks,  and 
adopted  a  special  attitude,  which  rendered  them  more 
procryptic. 

An  instance  has  been  given  of  the  use  of  an  aposeme 
on  certain  occasions  only.  The  following  is  a  very  re- 
markable instance  of  a  structure  useful  at  one  stage  of 
development  being  apparently  made  use  of  to  protect 
a  subsequent  stage. 

The  larva  of  the  Lasiocampid  moth,  Chrysopsyche  varia, 
is  quite  conspicuous,  being  coloured  a  rich  chestnut  brown 
with  large  pale  blue  spots.  When  full  grown  it  has  in 
addition  on  the  dorsum  of  each  segment  from  4-10 
a  dense  patch  of  very  short,  closely  set  fine  hairs  of 
glistening  white. 

It  has  been  already  mentioned  as  showing  peculiar 
limitations  of  instinct  (p.  200).  When  full  fed,  it  spins  a 
firm  brown  cocoon  of  the  type  usual  among  Lasiocampidae. 
The  point  of  interest  is  that  at  one  end  of  the  cocoon, 


USE   OF  LARVAL   APOSEME   BY  PUPA     217 

opposite  to  the  posterior  extremity  of  the  occupant,  a 
weak  spot,  ahiiost  a  hole,  is  left.  When  the  caterpillar 
becomes  a  chrysalis  the  discarded  brightly  coloured  larval 
skin  is  pushed  out  so  that  it  partly  projects  through  this 
hole.  It  is  naturally  to  be  expected  that  the  adult  moth 
would  emerge  through  this  hole,  but  it  does  not  ;  it  pushes 
its  way  out  in  the  usual  manner  through  the  other  end  of 
the  cocoon.  Now  if  the  object  of  the  weak  spot  is  to 
allow  the  discarded  larval  skin  to  be  extruded  so  as  not 
to  take  up  space  inside  the  cocoon,  one  would  expect 
it  to  be  got  rid  of  completely,  but  this  is  not  the  case  ; 
it  remains  partly  inside,  partly  outside, ^  its  bright  colours 
freely  visible.  Apparently  the  pupa  makes  use  of  the 
discarded  aposematic  skin  to  protect  itself.  I  have  not 
met  with  another  case  of  this  partial  extrusion  of  the 
larval  skin  through  an  orifice  especially  provided. 

Insects  furnished  with  well  marked  aposemes  are 
commonly  said  to  be  protected  by  the  possession  of  sting, 
distastefulness,  spines,  hairs,  irritant  fluid,  exceptional 
hardness,  etc.  It  must  be  understood  that  this  immunity 
from  attacks  by  birds  or  mammals  is  not  by  any  means 
claimed  to  be  absolute  at  all  times,  but  is  entirely  relative, 
depending  upon  the  abundance  of  insect  food  generally, 
of  that  species  in  particular,  and  the  state  of  hunger  of 
the  enemy,  who,  when  food  is  difficult  to  obtain,  will  eat 
species  which  he  would  pass  by  when  more  edible  insects 
could  be  easily  found. ^  Also  it  must  be  remembered  that 
certain  creatures  appear  to  be  specialized  for  devouring 
prey  which  others  pass  over. 

^  In  a  certain  nnmber  of  cases  the  skin  is  completely  extruded — 
evidently  the  habit,  if  it  is  of  protective  value,  has  not  yet  been  carried 
to  its  fullest  efficacy. 

2  See  Poulton,  E.  B.,  The  Colours  cj  Animals,  pp.  180,  181.  Marshall, 
G.  A.  K.,  The  Bionomics  of  South  African  Insects.  Trans.  Ent.  Soc. 
Lond.,  1902,  part  iii.  Swynnerton,  C.  F.  M.,  Proc.  Ent.  Soc.  Land., 
February  3,  1915;  and  in  "Experiments  and  Observations  bearing  on 
the  Explanation  of  Form  and  Coloviring."  Journal  Linn.  Soc,  1919» 
Zoology,  xxxiii. 


218  THE  COLOURATION   OF  INSECTS 

Thus  a  Roller  which  was  examined  at  Jinja  was  found 
to  have  devoured  numbers  of  a  bright  green  ball-rolling 
dung  beetle,  a  member  of  a  family  whose  habits  render 
them  nauseous  to  monkeys,  and  which  emit  a  very  foul 
smelling  fluid  when  handled. 

Bee-eaters  (Merops)  feed  on  bees  and  other  stinging 
HymenopteraP-  cuckoos  appear  to  feed  largely  on  very 
hairy  caterpillars.  Now  it  is  well  known  that  every  living 
thing  produces  very  many  more  offspring  than  can  possibly 
survive,  and  Wallace  pointed  out,  in  1858,^  that,  of  the 
offspring  of  one  pair,  on  the  average  all  but  one  must  die 
or  at  least  fail  to  produce  young.  So  that  any  one  who 
refuses  to  accept  the  explanation  that  aposematic  colours 
and  habits  are  produced  by  Natural  Selection  is  quite 
justified  in  saying,  "  If  you  claim  that  these  species  escape 
being  devoured  by  vertebrate  enemies,  the  burden  is  laid 
on  you  of  proving  by  what  means  they  are  prevented 
from  overrunning  the  earth." 

In  order  to  answer  this,  all  the  restraining  factors  must 
be  considered. 

Firstly,  there  are  the  vertebrate  enemies,  birds  and 
beasts,  against  which  it  is  claimed  aposematic  insects 
are  protected.  Secondly,  predaceous  insects,  such  as 
dragon  flies,  carnivorous  beetles  and  bugs,  and  Asilid 
flies,  which  eat  or  suck  juices  of  other  insects.  Spiders 
are  not  here  included,  for  they  appear  to  be  indiscriminate 
feeders  on  protected  and  unprotected  alike.  For  the 
same  reason  fossorial  Hymenoptera,  which  feed  their 
young  on  other  insects,  are  not  here  included.  Thirdly, 
there  are  parasitic  Hyinenoptera  and  Diptera,  which  lay 
their  eggs  on  other  insects  ;  and  fourthly,  the  micro- 
organisms of  disease. 

^  See  Reports  of  Sleeping  Sickness  Commission,  vol.  xiv,  1913,  pp.  15, 
16,  and  table  extracted  therefrom  in  Chap,  viii,  p.   172. 

*  "  On  the  Tendency  of  Varieties  to  depart  indefinitelj'from  the  Original 
TjT)e."  Essay  reprinted  in  Natural  Selection  and  Tropical  Nature,  1895 
edition,  pp.  2-i-5. 


ENEMIES   OF   PROTECTED   INSECTS        219 

Let  the  number  of  o£fspring  of  any  two  parents  destroyed 
by  each  of  these  agencies  be  represented,  in  order  as 
above,  by  V,  P  (with  above  described  Hmitations),  p  and 
M  :  then  if  X  be  taken  to  represent  the  total  number 
of  offspring,  X  —  1  represents  the  number  destroyed  by 
all  agencies  together.     So  the  equation  can  be  written  : 

X— l  =  V+P+i?  +  M. 

And  the  number  destroyed  by  any  one  agent  alone 

V  =  (X-l)-(P  +  2?  +  M). 

It  is  obvious,  therefore,  that  if,  as  is  claimed,  V  is  negligible 
for  protected  species,  P+2?+M  must  be  correspondingly 
greater,  and  there  is  some  reason  for  thinking  that  this 
is  actually  the  case,  although  much  statistical  evidence 
is  required.  1  For  instance,  in  the  case  of  P,  those  who 
have  paid  attention  to,  or  observed  in  the  field,  predaceous 
insects  with  their  prey,^  have  probably  had  the  same 
experience  as  myself,  that  the  prey  is  very  often  among 
precisely  those  species  which  are  believed  to  escape 
molestation  by  vertebrate  enemies.  Thus  I  found  a  com- 
pany of  spiny  black  and  yellow  larvae  of  Acraea  perenna, 
of  which  many  had  already  been  sucked  dry  by  a  bug,^ 
which  was  found  in  the  act  of  sucking  one.  This  one 
bug  might  very  easily  have  destroyed  seriatim  the  whole 
of  the  brood  of  these  aposematic  larvae.  In  the  case 
of  p  we  need  especially  comparative  statistics  showing 
the  relative  proportions  of  aposematic  and  cryptic  species 
that  are  destroyed  by  parasites  ;  the  following  bears  on 
the  subject.  Acraea  zetes,  a  typically  aposematic  scarlet 
and  black  butterfly,  abounded  on  Bagalla  Island,  and  its 

1  See  Trans.  Ent.  Soc.  Land.,   1902,  part  iii,  pp.   328-38. 
*  See  collected  data  by  Poulton,  Trans.  Ent.  Soc.  Land.,  19C6,  part  iii, 
pp.  323-409. 

^  Damarius  splendidulus. 


220  THE  COLOURATION  OF  INSECTS 

larvae,  ringed  alternately  with  orange  and  slate  grey, 
with  black  spines  and  crimson  head,  could  be  found  in 
numbers  when  full  fed  wandering  over  the  grass  land  in 
search  of  suitable  places  for  pupation.  Judging  by  the 
situations  in  which  the  pupae  were  found,  the  larva  chooses 
as  conspicuous  a  site  as  possible,  such  as  a  tall  grass  stem 
fully  exposed  and  unsheltered,  quite  out  in  the  open. 
Numbers  of  these  full  fed  larvae  and  of  the  equally  con- 
spicuous pupae  were  collected,  and  out  of  seventy,  77  per 
cent,  were  destroyed  by  parasitic  Diptera  (Tachinidae) 
and  Hymenoptera  {Chalcididae,  Braconidae). 

Lastly,  in  the  case  of  M.  The  very  peculiar  and  highly 
specialized  legless  caterpillars  of  the  Apodidae  are  often 
brilliantly  coloured,  and  furnished  with  intensely  sharp 
strong  spines  set  in  clusters,  often  said  to  be  "  poisonous," 
so  irritating  are  their  qualities.  The  Baganda  have  a 
great  dread  of  these  stinging  caterpillars,  which  they 
brought  me  with  the  utmost  caution.  I  was  very  seldom 
able  to  rear  them,  for  they  seemed  to  be  extraordinarily 
susceptible  to  some  disease  which  very  rapidly  killed 
them.  Possibly  it  was  of  the  same  nature  as  the 
"  pebrine  "  which  Pasteur  investigated  in  silkworms.^ 

A  very  interesting  special  case  of  aposematic  colouring 
is  the  development  of  "  Terrifying  "  marks,  and  just  as 
with  the  cases  previously  described,  the  colouration  is 
associated  with  a  special  attitude,  whose  purpose  is  to 
make  the  specialized  areas  of  colouring  suggest  some- 
thing that  frightens  or  discourages  the  enemy.  In  many 
cases  the  attitude  is  far  more  important  than  the  colouring. 
I  would  refer  the  reader  to  Poulton's  book,^  and  wish  here 
merely  to  describe  an  example  from  my  own  experience. 
The  large  and  handsome  moths  of  the  family  Saturnidae 
very  often,   like   our   "  Emperor  moth  "   of  the  heather 

*  Comparative  statistics  of  the  number  of  caterpillars,  procrj'ptic  and 
aposematic,  destroyed  by  p  and  M  would  bo  exceedingly  valuable. 
'  The  Colours  oj  A^iimals,  p.  258  et  seq. 


TERRIFYING  MARKS   AND   ATTITUDE     221 

moors,  have  large  eye-like  markings  on  the  hind  wings, 
which  are  concealed  by  the  fore  wings  when  the  moth 
is  at  rest,  but  under  certain  circumstances  are  exposed. 
One  of  these,  a  comparatively  dull  coloured  species,  was 
offered  to  my  pet  monkeys  on  Bugalla  Island.  The 
following  account  is  quoted  from  my  article  in  Bedrock.^ 

"  The  moth  was  a  large  yellow  species  with  well  marked 
eye -like  spots  on  the  hind  wings.  When  alarmed  it  bent 
the  body  ventrally  into  a  strong  curve,  and  held  the  wings 
in  a  very  curious  and  unusual  fashion — almost  upright, 
with  the  upper  surface  directed  forwards  so  that  the 
eye-like  markings  were  extremely  conspicuous  ;  indeed, 
the  attitude  was  obviously  intended  to  display  those 
*  eyes.'  The  moth  thus  looked  curiously  weird  and  un- 
mothlike,  and  the  monkeys  were  afraid  even  to  touch  it. 
It  was  not  merely  the  size  of  which  they  were  afraid, 
because  they  caught  and  readily  devoured  large  and 
protectively  coloured  moths  (Sphingomorpha)  often  found 
about  the  house." 

Finally,  it  must  not  be  concluded  that  all  bright  colours 
in  insects  are  aposematic.  In  the  case  of  butterflies  both 
surfaces  of  the  wings  must  be  considered  ;  only  the  lower 
surface  is  displayed  when  the  insect  is  at  rest  and  likely 
to  be  caught  unawares,  for  when  on  the  wing  a  butterfly 
is  alert  and  can  escape  by  flight.  Consequently  a  large 
number  of  species,  the  upper  surfaces  of  whose  wings  are 
vividly  coloured,  are  really  procryptic  if  the  lower  surfaces 
be  considered.  I  need  only  mention  our  English  "  Red 
Admiral,"  and  the  famous  leaf  butterflies  of  Asia  and 
Africa  [Kallima). 

Darwin  concluded  that  the  colours  of  butterflies  owed 
much  to  Sexual  Selection,  and  those  who  have  seen  butter- 
flies courting  will  probably  agree  that  vision  does  enter 
into  the  question.     I  have  seen  a  male  Bapilio  dardanus 

*  "  Notes  on  the  Struggle  for  Existence  in  Tropical  Africa,"  Bedrock, 
1913,  vol.  ii,  p.  366. 


222  THE  COLOURATION  OF  INSECTS 

in  headlong  flight  through  the  forest  suddenly  arrest  its 
course  and  dally  awhile  with'  an  Amauris  niavius,  and  it 
was  impossible  to  resist  the  conclusion  that  the  swallow- 
tail had  for  a  moment  mistaken  the  Amauris  for  its  own 
female  of  the  form  hippocoon,  which  closely  resembles 
Amauris.  Eltringham  ^  has  described  an  elaborate  appar- 
atus in  male  Amauris  which  I  was  fortunate  enough  to 
observe  being  actually  used  in  courtship  by  A.  psyttalea, 
on  Bugalla  Isle,  in  July  1912.  A  male  was  flying  about 
after  a  female,  which  presently  alighted  on  a  dead  flower 
spike  of  a  common  herb  about  two  feet  high.  She  sat 
almost  at  the  top,  vertical,  with  head  upwards  and  wings 
outspread,  and  remained  perfectly  still  while  the  male 
hovered  a  few  inches  above  her  head  with  a  peculiar 
flutter  causing  him  to  rise  and  fall  a  little.  Every  now 
and  then  the  flaps  at  the  extremity  of  the  body  were  widely 
everted  at  right  angles  to  the  body,  and  a  large  white 
brush-like  structure  was  most  energetically  protruded  and 
as  rapidly  withdrawn.  I  watched  this  for  a  minute  or 
two,  and  then,  to  my  surprise,  for  I  had  made  no  move- 
ment, the  female  suddenly  flew  away  as  if  the  performance 
had  not  appealed  to  her,  and  the  male  followed. ^ 

The  importance  of  the  scent  emitted  by  male  butterflies 
was  first  recognized  by  Fritz  Muller,^  who  described  certain 
scales  on  the  wings  especially  formed  for  producing  scent. 

A  very  curious  and  unusual  occurrence  was  noted  on 
Bugalla  on  October  25,  1912,  A  male  of  -a  small  and 
abundant  Syntomid  moth  {Epitoxis  albicincfa)  was  on  a 
grass  stem,  and  a  male  of  the  common  butterfly  Acraea 
terpsichore  form  ventura,  in  a  state  of  great  excitement, 
was  endeavouring  to  effect  union  with  the  moth,  passing 

^  Trans.  Ent.  Soc.  Lond.,  1913,  part  ii,  p.  399  et  seq.  ;  also  1915,  part  i, 
p.    152  et  seq. 

^  For  observations  showing  the  relation  of  these  anal  tufts  to  the 
"  brands  "  on  the  hind  wing,  see  Lamborn,  Proc.  Ent.  Soc.  Lond.,  1911, 
p.  xlvi ;   1912,  p.  xxxiv  ;   1918,  p.  clxxii. 

»  Jen.  Zeit.,  vol.  xi.  p.  99;    Trans.  Ent.  Soc,  1878,  p.  211. 


COURTSHIP  OF  BUTTERFLIES         223 

the  tip  of  its  abdomen  repeatedly  over  that  of  the  moth. 
It  was  the  more  curious  that  there  were  numbers  of  freshly 
emerged  Acraea  females  in  the  neighbourhood  with  which 
the  male  butterfly  could  have  mated.  Professor  Poulton 
suggested  that  possibly  it  was  a  case  of  accidental  likeness 
between  the  odours  of  two  species  very  far  removed  from 
each  other,  which  implies  that  the  male  seeks  for  the  odour 
of  the  female  as  well  as  trying  to  charm  her  with  his  own. 

White  butterflies  of  the  genus  Belenois  have  often  been 
observed  courting.  A  male  for  a  long  time  flutters  round 
and  pursues  a  female,  who,  perhaps  wearied  by  his  im- 
portunities, settles  at  last  with  wings  expanded.  The 
male  alights  behind  her  and  commences  vigorously  to 
"paw"  her  hind  wings  with  quick  movements  of  his 
anterior  legs,  the  action  being  as  if  he  was  trying  to  walk 
up  a  very  slippery  surface.  Refusal  on  the  part  of  the 
female  seems  to  be  indicated  by  a  curious  attitude.  The 
wings  are  spread  out  flat,  but  not  quite  at  right  angles 
to  the  axis  of  the  body,  for  the  fore  wings  are  directed 
slightly  backwards.  The  abdomen  is  directed  vertically 
upwards  at  right  angles  to  the  thorax. 

In  1917  I  witnessed  the  consummation  of  a  courtship 
of  a  Pierine,  the  initial  stages  of  which  had  not  been 
observed.  A  male  and  female  Pinacopteryx  simana  were 
fluttering  in  the  air  and  the  female  suddenly  settled, 
quite  quietly,  and  sat  with  wings  closed.  The  male  stood 
over  her  with  wings  widely  expanded  so  as  completely 
to  conceal  her  ;  the  union  was  the  act  of  a  moment,  and 
then  they  flew  away,  the  female  hanging  passively  with 
wings  closed,  the  male  carrying  her. 

Nymphalines  such  as  Precis  and  Byblia,  however,  adopt 
different  methods  of  courtship.  The  female,  with  wings 
closed  over  her  back,  faces  the  male,  who  endeavours 
to  induce  her  to  allow  the  union  by  butting  against  her 
closed  wings  with  the  anterior  margin  of  his  own,  brought 
together    over   his   back.     It   appears   as   if   the   male's 


224  THE   COLOURATION   OF  INSECTS 

endeavour  is  to  approach  from  the  flank  or  rear,  and  the 
female,  unless  willing,  turns  so  as  always  to  face  him. 

In  the  case  of  Acraeines  little  time  seems  to  be  wasted 
on  persuasion.  A  male,  in  the  air,  makes  for  the  female, 
who  at  once  falls  fluttering  to  the  ground,  where  the  two 
seem  to  struggle  together.  If  the  female  is  willing,  union 
is  almost  immediate  ;    if  not,  the  male  soon  flies  away. 

On  August  2,  1918,  in  Portuguese  East  Africa,  I  saw  a 
very  good  illustration  of  this.  A  fresh  specimen  of  Acraea 
natalica  was  flitting  aimlessly  about,  and  I  was  awaiting 
an  opportunity  of  catching  it,  when  an  old  and  very  worn 
female  came  by.  The  male  at  once  went  to  her,  and  she 
fell  straight  to  the  ground.  I  watched  for  several  minutes. 
The  male  was  very  excited,  and  gripped  the  female  with 
his  legs  round  the  roots  of  the  wings,  but  she  lay  motionless 
on  the  ground  adopting  an  attitude  of  passive  resistance, 
the  wings  folded  against  her  body  and  pressed  closely, 
so  as  to  prevent  the  male  thrusting  his  abdomen  down  to 
meet  hers,  which  he  struggled  to  do.  After  a  little  he 
managed  to  pass  his  abdomen  between  her  wings,  but 
she  made  no  response,  and  he  suddenly  gave  up  and  flew 
away.  I  caught  him,  and  then  found  the  female  still 
lying  motionless  on  the  ground,  and  secured  her  too. 

In  connection  with  the  pairing  of  butterflies,  the  following 
is  of  interest  to  evolutionists. 

During  the  nuptial  flight  it  is  known  that  in  the  case 
of  some  species  the  male  carries  the  female,  in  other  cases 
the  positions  are  reversed,  the  one  that  is  carried  remaining 
absolutely  passive  with  wings  closed.  In  a  discussion  on 
Sexual  Selection  among  insects  in  the  Descent  of  Man,^ 
Darwin  remarks  on  some  cases  where  the  male  is  "  less 
bright  "  than  the  female, ^  and  points  out  that  in  the 
English  Pieris,  CoUas  and  Epinephele  janira  the  duller  male 
is  supported  during  the  nuptial  flight  by  the  female,  "  so 

^  Chapter  xi. 

*  The  Lycaenid  butterfly  Lnchnocnema  bibulus  has  a  dull  brown  male 
which  is  pursued  in  courtship  by  the  brighter  blue-marked  female. 


NUPTIAL  FLIGHT  OF  BUTTERFLIES       225 

th.at  the  part  which  the  two  sexes  play  is  reversed,  as  is 
their  relative  beauty,"  and  Darwin  goes  on  to  say  that 
it  may  be  supposed  that  the  female  takes  the  more  active 
part  in  the  wooing.  Since  the  middle  of  1917  I  have  paid 
particular  attention  to  this  point,  and  a  large  number 
of  pairs  have  been  noted  on  the  wing.  In  the  Pierines,i 
in  all  cases  save  one,  the  male  has  carried  the  female 
as  above  described.  So  that  it  would  appear  that  Darwin 
was  misinformed  regarding  Pierines,  unless  our  English 
species  have  different  habits.  My  few  observations  of 
Nymphalines  show  that  the  female  carries  the  male. 
This  appears  alsg  to  be  the  case  with  Lycaenidae. 
Acraeines  show  no  definite  rule.  In  the  case  of  Satyrines 
the  female  seems  to  carry  the  male,  and  I  have  seen 
Papilio  dardanus  form  hippocoon  carrying  the  male. 

We  now  come  to  the  consideration  of  Mimicry,  one  of 
the  most  fascinating  subjects  for  study  that  insects  can 
provide,  and  one  on  which  a  large  amount  of  work  has 
been  done  in  recent  years,  from  the  point  of  view  of  the 
Darwinian  hypothesis,  thanks  to  the  influence  of  Professor 
Poulton,  of  the  Hope  Department  at  Oxford. 

The  study  of  mimicry  was  first  taken  up  by  Bates, 
who,  on  the  Amazons,  found  that  a  large  number  of 
abundant  butterflies  were  of  the  type  previously  alluded 
to  as  aposematic,  but  that  others,  although  superficially 
resembling  the  former,  belonged  to  groups  anatomically 
very  different  from  them.^ 

He  put  forward  the  explanation  that  these  latter  lived 
on  the  unsavoury  reputations  of  their  associates,  or,  in 
other  words,  were  Mimics  of  more  distasteful  models. 
He  found  that  whereas  the  models  were  abundant,  easy 
to  catch,  and  avoided  by  birds, ^  the  mimics  were  less 

1  Proc.  Ent.  Soc,  1918,  p.  clii.  *  Loc.  cit. 

*  Bearing  on  this  ia  the  fact  that  Acrseinea  and  Danaines  rarely  show 
evidence  of  attacks  by  birds  which  is  so  common  among  Lycaenidae, 
unprotected  Pierines  or  NymphaHnes,  Satyrines,  etc.,  in  which  a  ^- 
shaped  piece  is  symmetrically  cut  out  from  both  hind  wings,  showing 
the  nip  of  a  bird's  beak. 

16 


226  THE   COLOURATION   OF  INSECTS 

abundant,  shy,  and  easily  alarmed,  and  there  was  no 
evidence  that  they  also  were  distasteful.  On  reflection 
it  is  quite  obvious  that  a  mimic  must  be  less  abundant 
than  its  model,  for  if,  of  a  series  of  conspicuous  insects 
met  with  some  are  edible  and  others  distasteful,  an  enemy 
might  find  it  worth  while  to  catch  every  one  he  saw  on 
the  chance  of  it  being  edible.  If,  however,  the  proportion 
of  edible  to  distasteful  is  very  low,  the  chance  of  finding 
an  edible  specimen  is  too  small  to  make  it  worth  while 
catching  large  numbers  that  will  not  be  eaten. 

The  mimic,  as  has  been  said,  is  easily  alarmed,  and  it 
is  not  difficult  to  understand  the  reason.  It  has  been 
pointed  out  above  that  aposematic  species,  which  serve 
as  models,  are  extremely  resistant  to  harm,  and  even 
if  caught  and  tasted  do  not  of  necessity  suffer  vital 
injury.  Mimics,  however,  come  from  a  stock  which  has 
in  the  past  relied  for  safety  upon  concealment  or  rapidity 
of  flight,  and  have  not  developed  the  toughness  of  their 
models  ;  hence  a  nip  by  a  bird's  beak  or  the  rough  handling 
of  a  monkey  may  cause  fatal  damage. 

So  that  one  finds  by  experience  that  so  long  as  mimics 
are  not  alarmed,  they  have  a  great  resemblance  in  move- 
ment and  habits  to  the  aposematic  species  with  which  they 
are  associated.  If  a  mimic  is  frightened  it  takes  to  flight 
and  dashes  off  at  a  great  speed,  whereas  the  model 
will  merely  move  a  little  way,  and  often  come  back 
to  the  same  spot,  or  may  not  even  deign  to  move  away 
at  all. 

Here  again  is  well  exemplified  the  action  of  natural 
selection  in  producing  changes,  not  only  in  colouration 
and  shape,  but  in  the  nervous  system  also,  yet  only  so 
far  as  such  changes  are  required.  Thus  in  certain  mimetic 
South  American  Pierines,  a  small  part  of  the  fore  wing 
that  is  normally  concealed  by  the  hind  wing  retains  the 
hue  from  which  this  grouji  has  derived  the  name  of 
"  Whites,"  while  the  visible  areas  of  the  wings  are  mimetic 


IMPORTANCE   OF  ATTITUDE   IN  MIMICRY    227 

of  a  brightly  coloured  model. ^  Again,  instincts  are 
modified  so  long  as  the  assumed  attitudes  and  move- 
ments are  needed  to  correspond  with  the  false  appear- 
ance of  inedibility,  but  when  these  are  no  longer  helpful, 
rather  a  danger,  the  recently  acquired  instinct  of  deceit 
is  abandoned,  and  the  more  deeply  seated  instinct  of 
flight  comes  into  action. 

Attitude  is  of  very  real  importance  in  producing 
mimetic  resemblance,  and  living  specimens  often  appear 
mimetic  when  in  the  cabinet  they  do  not.  So  that  the 
ignorant  remark,  which  may  sometimes  be  seen  in 
print,  that  mimicry  is  the  product  of  the  imagination 
of  an  '*  arm-chair  philosopher  "  need  not  be  seriously 
considered. 

One  day,  on  Damba  Island,  I  was  looking  at  a  nest 
of  the  tree  ant,  jEcophylla,  among  the  leaves  of  a  bush. 
This  species,  by  means  of  silk  spun  by  a  larva  held  for 
the  purpose  by  an  ant,  fastens  together  leaves  to  make 
a  more  or  less  globula>r  nest  about  the  size  of  a  cocoanut. 
Wishing  to  obtain  a  few  specimens  I  proceeded  to  box 
them,  when,  to  my  great  astonishment,  one  of  them 
jumped,  thus  revealing  itself  to  be  no  ant,  but  a  mimetic 
spider, 2  which  had  been  running  about  unperceived 
among  the  ants  ! 

The  wonderful  thing  about  this  case  is  the  great 
anatomical  difference  between  ant  and  spider,  both 
internal  and  external.  The  model  has  head,  thorax, 
and  abdomen  separated  from  each  other  by  well  marked 
constrictions,  but  the  spider  has  head  and  thorax  fused 
into  a  cephalo-thoracic  mass,  separated  from  the  abdomen. 
The  ant  has  three  pairs  of  legs,  the  spider  four  ;  the  ant 
has  a  pair  of  long  mobile  antennae,  the  spider  none. 
Diagrammatically  the  difference  is  shown  overleaf. 

*  Poulton,  Essays  on  Evolution,  p.  239. 

2  Myrmarachne  Joenissex.  Another  spider  mimic  of  the  same  model  is 
described  and  figured  by  Shelford  in  A  Naturalist  in  Borneo,  pp.  230-1. 


228  THE   COLOURATION   OF   INSECTS 

These  dififerences  are  sufficiently  obvious  in  the  dead 
specimens,  and  the  quick  nervous  movements  of  a  live 
ant  with  waving  antennae  are  as  different  as  possible 
from  those  of  a  typical  spider. 

Nevertheless  in  this  case  the  spider  completely  deceived 
me.  How  was  it  done  ?  Firstly,  the  shape  is  unusual 
for  a  spider,  the  cephalo-thorax  and  abdomen  being  thin 
and  prolonged,  and  a  constriction  in  the  cephalo-thorax 
of  the  spider  represents  the  division  between  head  and 
thorax  of  the  ant.  The  spider  did  not  use  the  first  pair 
of  legs  for  walking,  but  they  were  held  up  in  the  air  and 
waved  about  to  copy  the  movements  of  the  antennae 
of  the  model.  It  is  obvious  that  this  functional  modi- 
fication necessitates  a  profound  alteration  in  the  neuro- 
muscular system  of  the  spider.  It  is  worth  noting,  too, 
how  in  the  last  extremity  the  spider  disclosed  its  true 
nature  in  its  endeavours  to  escape  by  jumping,  a  habit 
common  to  the  family  to  which  it  belongs  (Salticidae), 
but  suppressed  by  the  new  mimetic  instinct  until  an 
emergency  arose.  This  spider  wa?  not  the  only  mimic 
of  ^cophylla,  for  running  among  them,  and  almost  as 
closely  resembling  them  as  did  the  spider,  was  a  small 
bug  of  the  family  Capsidae}  which  proved  to  be  not  only 
an  undescribed  species,  but  sufficiently  distinct  to  be 
placed  in  a  new  genus. 

It  is  of  course  easier  for  a  bug  than  a  spider  to  be  brought 
to  resemble  an  ant,  since  both  are  insects,  and  natural 
selection  has  the  same  basis  to  work  upon.  It  might 
be  supposed  that  the  wings  and  wing  covers  of  the  mimic 
would  prove  a  difficulty,  since  they  lie  over  the  abdomen, 
but  in  Xenetomorpha  there  is  a  constriction  near  the 
base  of  the  wing  covers  which,  seen  from  above,  matches 
the  constriction  between  thorax  and  abdomen  of  the 
ant.  The  bug  lives  among  its  models,  probably  sucking 
the  juices  from  the  stems  of  the  leaves  among  which 

1  Xenetomorpha  carpenter i. 


ax™. 


QjL-dLer»v\4y»v 


M^I 


?ji^ 


SPIDER  . 


IMAGINARY   CASE   OF    MAMMALIAN    MIMICRY. 
Diaii'ii  by  Dr.  H.  Eltringhain. 


IMAGINARY  MIMETIC   RABBIT  229 

the  nest  is  made.  The  spider  catches  flies,  and  on  one 
occasion  was  actually  seen  to  run  into  the  outer  spaces 
of  the  nest  with  its  prey.  The  wonderful  nature  of  this 
mimicry  of  an  ant  by  a  spider  may  be  brought  out  by 
an  imaginary,  but  parallel,  example  for  the  benefit  of 
those  unaccustomed  to  deal  with  insects,  and  unfamiliar 
with  the  important  differences  between  ant  and  spider. 
It  is  probable  that  tortoises  are  not  eaten  by  those 
carnivorous  animals  which  prey  upon  rabbits.  Let  us 
imagine  a  farmer  in  the  country  seeing  what  he  thought 
was  a  tortoise,  and  idly  watching  it  crawling  about  in 
the  characteristic  tortoise  fashion.  He  goes  up  to  it  and 
frightens  it,  when,  to  his  astonishment,  it  bounds  away 
with  the  typical  rabbit  gait.  He  shoots  it,  and  on  ex- 
amination finds  all  the  essential  features  of  a  rabbit  : 
it  has  rodent  teeth,  but  the  external  ears  are  so  small 
as  to  be  unnoticeable.  The  main  resemblance  to  a  tortoise 
is  produced  by  a  matting  together  of  the  hair  on  the 
back  to  form  a  carapace-like  structure, ^  and  on  the  legs 
to  look  like  scales,  while  the  legs  themselves  are  much 
reduced  in  length,  but  very  thick. 

A  species  which  "  assumes  a  virtue  though  it  has  it 
not  "  is  a  true  mimic,  and  is  said  to  be  Pseud-aposematic, 
or  to  have  false  warning  colours,  for  it  appears  in  the 
guise  of  another  more  fortunate  than  itself  in  the  possession 
of  distasteful  qualities.  But  when  the  mimetic  association 
first  described  by  Bates  was  more  fully  investigated, 
some  of  the  members  were  found  to  be  quite  as  abundant 
as  the  species  which  they  resembled,  and  to  belong  to 
groups  which  could  be  claimed  to  be  as  well  protected  as 
the  models.  It  was  pointed  out  previously  that  a  mimic 
must  be  less  abundant  than  its  model.  Fritz  Muller 
first  pointed  out  how  a  distasteful  and  abundant  species 
can  gain  by  resembling  anothey  equally  distasteful  and 

^  Compare  the  so-called  horn  of  a  rhinoceros,  which  is  structurally 
merely  agglomerated  hair. 


230  THE   COLOURATION  OF  INSECTS 

abundant.  In  a  brief  preliminary  statement  in  1878  ^ 
he  says  :  "  What  advantage  can  it  be  to  a  creature  pro- 
tected by  repellant  odour  to  resemble  another  similarly 
protected  species  ?  If  their  foes  avoid  protected  species 
by  *  instinct,'  none  at  all  ;  but  if,  on  the  contrary,  as 
appears  so  much  more  probable,  the  foes  have  to  learn 
their  unpalatability  by  experience,  then  the  benefit  is  all 
the  greater  the  less  numerous  the  species.  The  advantage 
gained  by  two  unpalatable  species  by  their  resemblance 
is  in  inverse  ratio  to  the  square  of  their  numbers." 

This  quotation  may  be  amplified  a  little.  A  certain 
number  of  lives  of  any  species  must  be  sacrificed  in 
teaching  inexperienced  enemies  what  to  avoid.  But 
if  the  loss  of  insects  of  a  certain  definite  aposematic 
pattern,  instead  of  being  borne  by  one  species  only,  could 
be  distributed  over  several  resembling  each  other,  the 
loss  borne  by  each  species  would  be  only  a  small  pro- 
portion of  the  total  loss,  while  the  lesson  would  be  equally 
well  learnt.  Moreover,  it  will  be  of  further  advantage 
in  that  there  will  be  fewer  patterns  to  tax  the  enemy's 
memory. 

So  now  we  have  to  consider  a  second  type  of  resemblance, 
characterized  by  the  presence  of  Common  Warning  Colours, 
or,  to  use  Poulton's  term,  Syn-aposematic.  Although  the 
term  "  Mimicry,"  first  used  by  Bates,  should  refer  to 
an  edible  species  masquerading  as  inedible,  it  is  loosely 
used  to  cover  the  likeness  between  two  distasteful  species, 
which  is  a  matter  of  a  different  order.  Properly  speaking, 
Mimicry  is  Pseud-  and  not  /Si/w-aposematic. 

Instances  of  syn-aposematic  resemblance  may  be  seen 
in  England,  such  as  the  yellow  and  black  bands  of  different 
kinds  of  wasps,  or  the  red  and  green  of  the  Burnet  moths. 
These  insects  being  so  closely  related,  it  may  with  reason 
be  argued  that  it  is  not  surprising  that  Burnet  moths 
of  a  single  genus  should  have  a  close  similarity. 

*  See  Proc.  Enl.  Soc.  Lond.,   1915,  pp.  xxii,  xxiii. 


SYNAPOSEMATIC  ASSOCIATIONS        281 

As  a  better  instance  may  be  cited  a  number  of  Hymen- 
optera  of  different  groups  which  I  found  on  the  islands, 
characterized  by  dark  grey  or  dull  black  colouring  with 
a  segment  of  the  antennae  and  the  tip  of  the  abdomen 
conspicuously  white,  and  the  transparent  wings  partly 
clouded  to  form  a  pattern.  Several  species  of  Fossorial 
and  Parasitic  Hymenoptera  were  collected  that  belonged 
to  this  syn-aposematic  association  ;  in  one  case,  a  Scoliid, 
the  white  on  the  antennae  was  produced  by  white  hairs, 
and  was  not,  as  in  the  other  species,  the  colour  of  the 
integument.  This  is  an  interesting  example  of  a  point 
with  which  Professor  Poulton  has  dealt  at  some  length, ^ 
that  natural  selection  has  brought  about  the  same  effect 
in  different  ways  on  different  subjects,  according  to  the 
material  offered  for  selection.  Natural  selection  can 
originate  nothing  ;  it  can  only  work  with  and  modify 
material  offered  to  it  by  variation.  This  point  can  never 
be  kept  too  much  in  prominence. 

The  best  known  syn-aposematic  association  centres 
round  the  undoubtedly  distasteful  and  conspicuous  Mala- 
coderm  beetles  of  the  family  Lycidae — such  insects  are 
very  conveniently  spoken  of  as  "  Lycoid."  The  Lycid 
aposeme  is  a  general  colouration  of  bright  orange-brown, 
with  the  extremity  of  the  abdomen  and  elytra  black. 
The  antennae  and  limbs  are  black  or  black  and  orange. 
The  beetles  are  found  collected  in  numbers  ^  on  flowering 
bushes,  are  of  sluggish  habit,  slow,  heavy  flight,  unafraid, 
and  often  exude  a  droplet  of  yellow  fluid  when  handled, 
and  have  been  proved  to  be  distasteful  to  vertebrate 
enemies.'  G.  A.  K.  Marshall  figured  4  a  large  number 
of  Lycoid  insects  belonging  to  many  orders  of  insects. 
In  beetles  and  bugs  {Hemiptera)  the  species  are  coloured 

^  See  Essays  on  Evolution,  pp.  2G4-6  ;  also  Punnett,  Mmiicry  in 
Butterflies,  pp.  40-2. 

2  Proc.  Ent.  Soc.  Land.,   1917,  p.  Ivii. 

»  Trans.   Ent.  Soc.   Lond.,    1902,   Part   III,  pp.   347,   391. 

«  Ibid. 


232  THE   COLOURATION  OF  INSECTS 

in  the  same  way  as  in  the  Lycidae.  In  the  clear  winged 
Hymenoptera  the  wings  are  tinted  with  orange,  and,  at 
their  tips,  with  black,  so  that  when  brought  together 
over  the  body  they  produce  the  Lycoid  effect.  Lycoid 
beetles  are  numerous.  I  have  met  with  them  among 
the  families  Cerambycidae,  Chrysomelidae,  Cetoniidae,  and 
their  closer  Malacoderm  relations,  Lagriidae.  Of  Hymen- 
optera, the  fossorial  Sphegidae  and  Pompilidae,  true 
wasps,  and  parasitic  Braconidae,  all  had  Lycoid  repre- 
sentatives on  the  islands  ;    also  Hemiptera. 

A  small  moth,  of  family  Lithosiidae,  abounded  among 
long  grass  on  Bugalla  Isle,  and  as  it  rested  with  its  wings 
superimposed  upon  its  back,  the  resemblance  to  a  Lycid 
was  quite  striking.  This  was  less  so  in  the  case  of  a  new 
species  of  Zygaenid  moth  ^  which  I  was  fortunate  enough 
to  find.  The  wings  were  laid  along  the  side  of  the  body 
in  the  usual  Zygsenid  manner,  so  that  the  fiat  appearance 
of  the  model  beetle  was  lacking.  Many  of  these  Lycoids 
could  be  found  at  the  same  time  as  the  Lycid  beetles 
on  the  flowers  of  Haronga  madagascariensis,  a  tree  or 
shrub  very  abundant  on  the  islands,  and  known  as  the 
"  Gamboge  "  tree. 

The  Lycid  aposeme  is  not  confined  to  Africa.  Shelf ord^ 
gives  a  long  list  of  Lycoid  insects  met  with  in  Borneo, 
some  of  which  are  syn-aposematic,  while  others  are 
probably  pseud-aposematic. 

Mimicry,  using  the  term  in  its  widest  sense,  it  to  be 
found  with  every  degree  of  relationship  between  the 
insects  concerned.  I  have  drawn  up  a  table,  from  examples 
met  on  the  islands,  showing  this  graphically.  At  the  top 
of  the  column  of  species  will  be  found  the  pair  in  which 
model  (uppermost)  and  mimic  are  as  closely  related  as 
possible,  being  members  of  the  same  genus.  At  the 
bottom  of  the  column  model  and  mimic  are  as  far  apart 
as  members  of  the  Phylum  Arthropoda  can  be.     Between 

^  Saliunca  egeria.  ^  A  Naturalist  in  Borneo,  p.  241. 


MODEL  AND  MIMIC 


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234  THE   COLOURATION   OF  INSECTS 

these  two  is  a  series  of  pairs,  model  uppermost,  showing 
every  grade  of  relationship. 

Mimicry,  looked  at  from  one  point  of  view,  is  merely 
an  example  of  resemblance  to  an  especial  part  of  the 
environment,  and  is  strictly  analogous  to  special  pro- 
cryptic  resemblance.  Both  are  forms  of  Apatetic  coloura- 
tion.^  In  one  case  the  insect  is  like  a  leaf  or  twig  which 
is  of  no  interest  to  an  insectivorous  enemy  ;  in  the  other 
it  resembles  another  species  which  the  enemy  rarely 
eats,  knowing  it  to  be  distasteful.  There  seems  no  logical 
reason  for  supposing  that  the  latter  example  is  beyond 
the  power  of  natural  selection  any  more  than  the  former, 
yet  in  spite  of  much  recent  work  on  these  lines  by  the 
Hope  Department,  and  also  by  naturalists  in  the  field, 
it  is  held  by  some  that  the  resemblances  are  fortuitous, 
or  the  result  of  causes  which  together  or  separately  are 
not  able  to  explain  facts  as  are  the  Batesian  and  Mullerian 
theories,  based  on  natural  selection. 

An  objection  is  sometimes  urged  somewhat  as  follows. 
Since  the  potential  numbers  of  patterns  are  limited,  and 
the  number  of  species  large,  it  is  quite  possible  that  the 
same  pattern  may  have  been  accidentally  produced  in 
two  species  without  there  being  any  meaning  to  be  attached 
to  the  resemblance,  except  mere  coincidence. 

Dr.  F.  A.  Dixey  dealt  with  this  argument  at  the 
meeting  of  the  British  Association  at  Birmingham  in 
1913.2  He  showed  a  number  of  examples  of  Lepidoptera 
from  different  continents  with  approximately  the  same 
colouration  and  pattern,  and  to  these  cases  it  would 
of  course  be  absurd  to  ascribe  a  mimetic  significance. 
But  it  is  important  to  note  that  such  coincidence  has 
gone  no  further  than  to  produce  the  crudest  of  patterns 
and  contrasts,  such  as  a  light  subapical  bar  on  a  dark 
fore  wing,  and  the  likeness  even  then  is  not  so  close  as 

^  Colours  of  Animals.     See   classification   at   end. 
*  See  Report,  p.  618. 


THE   SELECTIVE   AGENTS  235 

between  species  of  Planema  and  their  mimics,  forms  of 
Pseudacraea. 

Coincidence  has  proved  itself  unable  to  produce  such 
cases  as  those  in  South  America  described  by  Bates, 
where  the  colouration  is  a  comparatively  complicated 
mixture  of  red  and  yellow  on  a  dark  background.  These 
cases,  indeed,  almost  seem  to  be  an  exception  to  the  rule 
stated  above,  that  aposematic  patterns  are  extremely 
simple. 

The  geographical  variations  of  a  mimetic  species, 
according  to  the  different  species  serving  as  models  in 
the  various  subdivisions  of  its  habitat,  such  as  in  the 
case  of  Acraea  alciope  ^  or  Pseudacraea  eurytus  (see  next 
chapter),  with  the  transitional  forms  at  the  meeting 
points  of  two  areas,  are  extremely  difficult  to  explain, 
except  by  the  theory  of  a  causal  connection  between 
model  and  mimic. 

One  of  the  great  difficulties  felt  by  many  to  militate 
against  acceptance  of  the  theory  of  mimetic  resemblance 
produced  by  natural,  selection  is  lack  of  definite  evidence 
of  a  selective  agent.  It  is  claimed  that  it  has  not  yet 
been  proved  that  birds  eat  butterflies  in  sufficient  numbers 
to  produce  selective  action,  and,  moreover,  that  they  have 
in  certain  cases  been  seen  to  devour  just  those  species 
which  are  claimed  to  be  exempt.  ^  This  latter  point  has 
been  already  dealt  with.  I  think  that  few  would  claim, 
for  instance,  that  the  sting  of  a  bee  is  of  no  protection 
to  it  because  the  Bee-eaters  appear  to  be  especially  fond 
of  them.  A  mimetist  would  account  for  such  cases  as 
the  ashy  wood  swallow  devouring  Danaines  in  this  way. 

Regarding  the  general  question,  there  is  plenty  of 
indirect  evidence  of  attacks  by  birds  upon  butterflies.  All 
collectors  must  have  noted  the  ^-shaped  gaps  in  the  hind 
wings,  symmetrical  on  both  sides,  that  could  only  have 

»  Bedrock,  No.    1,  April   1912,  pp.   57-64. 

*  Punnett,   Bedrock,  vol.   ii,   July   1913,   pp.    159-60. 


236  THE   COLOURATION   OF  INSECTS 

been  produced  by  a  portion  of  the  wings  enclosed  in  a 
bird's  bill  breaking  away,  as  I  have  previously  described. 
As  for  direct  evidence,  G.  A.  K.  Marshall  first  collected  a 
number  of  records  of  attacks  by  birds  actually  witnessed,^ 
but  C.  F.  M.  Swynnerton  has  recently  produced  such 
overwhelming  evidence, ^  that  there  can  no  longer  be  any 
doubt  about  the  matter.  His  many  careful  observations 
have  shown  that  attacks  on  butterflies  may  very  easily 
be  overlooked  unless  an  observer  is  especially  on  the  look 
out  for  them. 

For  instance,  the  late  F.  C.  Selous  said  :  "  I  have  never 
once  seen  a  bird  eat  a  butterfly  in  Africa."  {African 
Nature  Notes  and  Reminiscences,  p.  9.)  But  I  do  not 
see  that  the  negative  evidence  of  a  hunter,  who  did  not 
pay  so  much  attention  to  small  life  as  to  big  game,  weighs 
against  the  positive  evidence  brought  forward  by  Swynner- 
ton and  others,  who  have  paid  special  attention  to  birds 
and  butterflies  from  this  point  of  view. 

In  fact,  Selous's  statement  only  shows  how  much  an 
observer  may  fail  to  see  outside  his  particular  sphere 
of  interest  ! 

It  appears  to  me  that  observation  of  one  class  of  life 
renders  it  difficult  to  observe  another  ;  indeed,  there  are 
three  definite  fields,  requiring  radii  of  observation  of 
different  lengths.  First,  and  nearest,  are  insects  whose 
small  size  renders  it  necessary  to  look  for  them  near  at 
hand.  I  find  that  I  instinctively  keep  my  vision  on  objects 
within  about  ten  yards'  radius  when  I  am  out  in  the  field, 
insects  being  my  natural  prey.  Big  game  can  hardly 
be  expected  to  be  seen  within  this  area  !  If  it  is  desired 
to  observe  birds,  the  radius  is  longer,  and  one  looks  not 
on  the  ground  or  low  herbage  near  at  hand,  but  at  bushes 
and  trees  at  least  twice  as  far  away,  and  for  mammals 

»  Trans.  Ent.  Soc.  Loud,    1902,   Part  III,  pp.   353-71. 
^  Proc.  Ent.  Soc.    Lond.,    1915,    pp.    xxxii-xliii  ;    Journ.    Linn.  Soc, 
1919  ;  Zoology,  vol.  xxxiii. 


BIRDS   AND   BUTTERFLIES  287 

the  radius  is  much  increased,  I  have  often  noticed  that 
when  out  for  insects  I  notice  very  little  of  the  bird  life, 
and  if  I  want  to  see  birds  have  to  determine  to  ignore 
insects.  How  much  the  more  is  this  necessary  for 
mammals  ! 

If  an  entomologist  fails  to  observe  distant  game, 
equally  so  must  the  hunter,  who  is  looking  out  for  distant 
animals,  be  oblivious  to  much  that  goes  on  near  at  hand. 
The  habitual  gaze  of  such  a  practised  hunter  as  Selous 
would  be  fixed  beyond  the  shorter  radius  necessary  to 
observe  small  birds  and  their  prey.  This  seems  a  possible 
explanation  of  the  failure  of  a  great  hunter  to  see  what 
I  have  seen  on  several  occasions  in  a  fraction  of  the  time 
that  he  spent  in  the  field.  I  think,  speaking  from  my 
own  experience,  that  one  is  too  apt  only  to  notice  such 
birds  which,  perched  on  conspicuous  twigs  or  tree  tops, 
look  as  if  they  were  going  to  catch  butterflies,  such  as 
Bee-eaters,  Drongos,  etc.  At  any  rate,  that  has  been 
my  error  on  the  islands,  and  I  never  saw  a  Bee-eater 
attack  a  butterfly,  although  I  found  several  pairs  of  wings 
of  Terias  lying  on  the  ground  under  a  stem  where  Melit- 
tophagus  meridionalis  had  just  been  sitting.  Had  I  read 
Swynnerton's  work  before  I  collected  butterflies,  I  should 
certainly  have  seen,  as  Swynnerton  says,  "  a  sudden 
sharp  movement  at  the  back  of  a  flower  head  or  the 
quick  dash  of  a  bird  over  the  top  of  a  pannicle  on  which 
butterflies  and  Hymenoptera  may  be  feeding  together  ;  " 
for  birds  often  flew  away  at  my  approach  to  the  flowering 
bushes  of  Haronga,  on  which  great  numbers  of  butterflies 
fed. 

Since  I  left  the  islands  I  have  seen  a  bush  frequenting 
bird,  probably  Campephaga  nigra,  the  black  cuckoo-shrike, 
very  quietly  eating  a  Pierine  butterfly  (Belenois),  but 
had  I  not  heard  the  quick  flutter  of  wings  and  the  snap 
of  a  bill  as  it  caught  the  butterfly,  my  attention  would 
not  have  been  drawn  to  this  case. 


238  THE   COLOURATION   OF  INSECTS 

In  1915,  while  on  active  service  in  German  East  Africa, 
I  saw  two  wagtails  at  puddles  eat  eleven  butterflies  in 
five  minutes,  and  on  another  occasion  saw  one  eat  eleven 
butterflies  in  three  minutes,  definitely  selecting  for  its 
food  Lycaenidae,  Belenois,  Atella,  from  among  a  crowd 
of  butterflies  assembled  on  the  mud,  and  paying  no  atten- 
tion to  a  number  of  the  typically  aposematic  Danaine 
Amauris  echeria,  or  the  black  and  scarlet  Papilio 
ridleyanus,  mimetic  of  Acraea  egina.^ 

Lastly,  it  may  be  said,  when  dwelling  on  this  question 
whether  birds  do  or  do  not  by  eating  butterflies  cause 
mimetic  resemblances,  is  it  not  too  often  forgotten  that 
butterflies  are  not  the  only  mimics  ?  No  one  will  deny 
that  spiders  are  eaten  by  birds,  or  flies,  or  beetles,  or 
grasshoppers,  yet  numbers  of  mimetic  members  of  all 
these  groups  are  known,  all  explicable  by  the  same  theory 
as  mimicry  among  butterflies,  and  all  must  stand  or  fall 
together. 

Dr.  W.  H.  Longley  has  suggested  a  modification  of 
Thayer's  views  on  concealment,  supposing  that  all 
species  have  been  forced  to  assume  colour  combinations 
which  most  effectually  conceal  them  in  their  normal  en- 
vironment ;  and  that  in  a  few  cases  patterns  have  appeared 
which  have  been  sufficiently  alike  to  deceive  enemies 
which  discriminate  in  their  choice  of  food.^  This  hypo- 
thesis thus  evades  the  difficulty  of  understanding  the 
gradual  building  up  of  a  mimetic  likeness  while  acknow- 
ledging that  mimicry  does  exist  and  is  of  value  to  the 
mimic,  and  that  different  degrees  of  edibility  exist,  but 
it  affords  no  explanation  of  the  difference  in  behaviour 
between  model  and  mimic.  If  both  Planema  tellus  and 
Pseudacraea  eurytus  form  terra,  are  equally  well  concealed, 
why  should  the  former  be  so  bold  that  it  can  be  plucked 

^  Proc.  Ent.  Soc,   1915,  pp.  Ixix.-lxxv. 

'^  "  A  Revised  Working  Hypothesis  of  Mimicry,"  The  American  Natural- 
ist, vol.  li,  May  1917,  p.  276. 


LONGLEY'S   HYPOTHESIS  239 

from  a  flower  by  the  fingers,  while  the  utmost  caution 
is  necessary  if  one  wishes  to  catch  the  mimic  ?  Dr. 
Longley  lays  stress  on  the  assertion  that  "  colour  and 
habit  are  associated  variables,"  which  hardly  seems  to 
be  consistent  with  the  great  dififerences  in  habit  between 
model  and  mimic  of  the  same  colour  and  pattern.^ 

Again,  I  would  point  out  that  it  is  difficult  in  the 
extreme  to  think  of  all  larvae,  for  example,  as  concealed 
by  likeness  to  their  surroundings.  On  our  common 
hawthorn  bush,  for  instance,  caterpillars  of  the  gold 
tail  moth,  or  of  the  "  Figure  of  eight  "  moth  {Diloba 
caeruleocephala)  thrust  themselves  upon  one's  notice, 
and  side  by  side  on  the  same  bush  highly  modified 
Geometrid  larvae  are  only  to  be  discovered  by  careful 
search,  so  similar  are  they  to  twigs.  A  large  Hypsid 
larva  (pactolicus)  abounded  on  a  papilionaceous  plant 
growing  on  sandy  shores  of  the  islands  of  Lake  Victoria. 
It  was  marked  with  alternate  rings  of  dead  black  and 
purest  Chinese  white,  with  red  head  and  legs  and  long 
black  or  white  hairs,  and  was  visible  clearly  from  as 
far  away  as  a  creature  of  that  size  could  be  visible.  It 
developed  into  a  gorgeous  orange  moth,  with  blue-black 
blotches  on  the  fore  wings  and  a  black  border  to  the  hind 
wings,  which  was  a  brilliant  and  conspicuous  object  at 
rest  or  on  the  wing.  It  freely  exposed  itself,  and  was 
of  sluggish  habits  and  slow,  heavy  flight,  as  it  would  be 
expected  to  be  on  the  Darwinian  explanation.  Yet 
Dr.  Longley  would  have  us  believe  that  it  is  really  con- 
cealed, and  offers  no  consistent  explanation  of  its  habits. 

The  great  attention  that  is  nowadays  being  paid  to 
the  principles  of  heredity  as  expounded  first  by  Mendel, 
and  to  the  theory  of  "  Mutations,"  has  resulted  in 
attempts  to  account  for  cases  of  mimetic  likeness  by  sup- 

^  In  the  case  of  the  Lycidas  the  larvae  are  carnivorous  and  live  in  the 
open  ;  those  of  a  very  close  Longicorn  mimic  live  in  dead  wood.  At 
the  stages  when  the  future  similar  colours  of  the  adults  are  being  pre- 
pared the  habits  of  model  and  mimic  are  as  dissimilar  as  possible.. 


240  THE   COLOURATION   OF   INSECTS 

posing  that  a  mimic  was  produced  suddenly  in  the  likeness 
of  some  other  species,  by  a  large  variation  known  as 
a  mutation,  and  that  the  Mendelian  principle  perpetuated 
this  unchanged,  the  pattern,  etc.,  being  due  to  presence 
or  absence  of  certain  "  factors,"  or  of  factors  inhibiting 
others. 

.  If  mimics  are  produced  by  mutations,  it  is  remarkable 
that  not  only  superficial  aspect,  but  movements  and  habits 
should  be  produced  that,  quite  fortuitously,  are  extra- 
ordinarily like  those  of  some  other  species  in  the  same 
neighbourhood,  and  it  seems  highly  remarkable  that  such 
mutations  should  resemble  species  of  the  type  described 
as  aposematic.  How  is  it  that  mutation  does  not  pro- 
duce new  forms  resembling  procryptic  species  1  Why 
should  all  the  females  of  P.  dardanus  be  modified  by 
mutation  to  resemble  different  species  of  conspicuous, 
relatively  distasteful  butterflies  of  genera  belonging  to 
two  different  sub -families  ?  Why  has  not  a  form  of  the 
excessively  variable  species  Pseudacraea  eurytus  (see  next 
chapter)  been  produced  that  deceptively  resembles  some 
procryptic  species  1  This  most  wonderful  genus  has 
only  two  out  of  over  a  score  of  forms  that  are  not  close 
copies  of  some  other  butterfly,  and  yet  the  species 
resembled  are  all  aposematic  !  It  seems  incredible  that 
mutation  can  produce  only  pseud-aposematic  variation. 
Where,  then,  are  the  other  less  conspicuous  forms  ?  No 
other  conclusions  seem  possible  than  that  they  have 
been  destroyed  by  enemies  before  they  could  establish 
themselves.  If  this  be  so,  the  argument  that  insectivorous 
enemies  do  not  destroy  butterflies  in  sufficient  numbers 
to  have  a  selective  influence  falls  to  the  ground. 

As  a  matter  of  fact,  a  few  cases  are  known  of  such  a 
Variety  differing  very  considerably  from  its  parents  to 
a  degree  that  could  be  claimed  as  an  instance  of  the 
sudden  appearance  of  a  mutation. ^      But  they  are  ex- 

1  Bedrock,  vol.  i,  pp.  63-4 — an  example  of  a  rare  large  variation  in 
Acraea  alciope. 


INHERITANCE   OF  SMALL  VARIATIONS      241 

cessively  rare  compared  with  the  numerous  finely  gradated 
forms  that  may  be  found  connecting  a  mimetic  form 
with  a  non-mimetic  or  transitional  between  two  mimetic 
forms. 

That  birds  do  exercise  discrimination  and  do  destroy 
large  numbers  of  butterflies  there  can  no  longer  be  doubt, 
thanks  to  Swynnerton.  It  seems  difficult  to  avoid  the 
conclusion  that  the  conspicuous  mimics  are  ^preserved 
by  selection,  and  it  is  on  the  question  how  they  arose 
that  Darwinians  and  mutationists  join  issue. 

The  study  of  a  mimic  of  wide  distribution  and  changing 
form,  such  as  Acraea  alciope,  Pseudacraea  eurytus,  Charaxes 
etheocles,  shows  by  the  transition  stages  that  a  mimic 
is  not  suddenly  turned  out  complete.  Evidence  may  be 
found  in  the  publications  of  the  Entomological  Society  ^ 
that  the  small,  often  quite  small,  variations  on  which 
a  Darwinian  depends,  are  heritable,  whereas,  according 
to  the  mutationist,  such  "  fluctuations  "  are  not  handed 
down.  On  the  other  hand,  the  mutationist  claims  that 
his  large  variations  are  irrevocably  fixed,  and,  when  once 
formed,  do  not  retrogress  towards  the  parent  form.  Thus, 
for  instance,  the  wonderful  forms  of  Pseudacraea  eurytus, 
mimicking  different  species  of  Planema  according  to  the 
locality,  should,  if  the  model  ceased  to  exert  its  influence, 
still  continue  to  show  the  same  great  degree  of  resemblance 
without  the  occurrence  of  any  intermediate  variations. 
The  next  chapter,  however,  shows  that  this  is  not  the 
case. 

^  Poulton,  E.  B.,  "Heredity  in  Six  Families  of  P.  dardanus,  subsp. 
ceneay  Trans.  Ent.  Soc,  1908r  Carpenter,  G.  D.  Hale,  "  The  Inherit- 
ance of  Small  Variations  in  the  Pattern  of  Papilio  dardanus."  Trans. 
Ent.  Soc,  1914. 


17 


CHAPTER    XI 

PSEUDACRAEA    EURYTUS 

The  Nymph  aline  genus  Pseudacraea  is  closely  allied  to 
the  more  widely  spread  Limenitis,  but  is  confined  to 
the  Ethiopian  regions,  including  Madagascar.  The  name 
is  an  excellent  one  ;  for  out  of  a  considerable  number 
of  species,  although  the  number  has  been  much  reduced 
during  recent  years  owing  to  the  fusion  of  many  "  species  " 
into  one,  only  two  are  non-mimetic.  The  remainder 
resemble  for  the  most  part  members  of  the  Acraeine  genus, 
Planema,  a  few  mimic  Acraea  itself,  one  mimics  theDanaine 
genus  Danaida  and  others  ^mawm. 

One  of  the  most  remarkable  points  in  the  resemblances 
is  the  fidelity  with  which  a  single  polymorphic  species 
mimics  sundry  species  of  models  of  very  different  appear- 
ances in  different  localities  ;  and  where  a  model  is  sexually 
dimorphic  the  sexes  of  the  mimic  faithfully  copy  the 
corresponding  sex  of  the  model.  Yet  in  the  very  locality 
where  this  dimorphism  of  model  and  mimic  exists  other 
species  of  monomorphic  models  are  closely  copied  by 
monomorphic  forms  of  the  same  species  of  mimic. 

The  closeness  of  the  resemblance  is  most  remarkable, 
and  is  indicated  by  names  such  as  deceptor,  simulator, 
imitator,  etc.  Indeed,  as  Eltringham  saj'-s  in  his  Mimicry 
in  African  Butterflies,  the  deception  caused  Hewitson 
himself,  a  violent  opponent  of  Bates's  explanation  of 
these  resemblances,  to  comment  upon  the  strange  simil- 
arity between  Acraeine  and  Nymphaline. 

242 


THE   FLIGHT   OF  PSEUDACRAEA  243 

I  have  many  times  been  deceived  by  these  mimics 
in  the  forests  on  the  islands,  until  long  association  and 
close  familiarity  enabled  me  to  differentiate.  But  even 
then,  after  a  pause  of  a  few  weeks  during  which  they 
had  not  been  seen,  it  was  by  no  means  easy  to  say 
at  a  glance  whether  a  specimen  seen  suddenly  in  the 
forest  was  Planema  or  Pseudacraea.  Certainly  the  mimics 
are  not  so  bold  as  Planema,  and  if  really  alarmed  will 
show  it  in  their  hasty  flight,  whereas  the  model  is  much 
more  stoical,  and  may  be  easily  picked  off  a  flower  with 
the  fingers. 

The  flight  of  Pseudacraea  is  often  of  the  "  floating  " 
nature,  especially  when  several  of  these  butterflies  are 
flying  rather  high  up,  in  the  sun,  and  round  about  a  tree. 
By  this  the  mimic  can  be  distinguished,  but  some  species 
of  Pseudacraea,  e.g.  poggei,  do  not  show  the  "  floating  " 
flight  to  the  same  degree,  and  thus  poggei  bears  an  even 
closer  resemblance  to  its  model,  Danaida  chrysippus, 
whose  flight  is  much  more  of  the  "  flapping  "  type. 

Professor  Poulton  has  written  as  follows  about  this 
flight  in  a  letter  dated  September  5,  1912  :  "I  am  very 
interested  in  the  non-floating  flight  of  the  most  distaste- 
ful butterflies.  But  I  have  seen  a  kind  of  floating  flight 
in  D.  plexippus  in  America.  Still  this  is  not  like  our 
Limenitis,  and  this  latter  I  suspect  is  like  Pseudacraea. 
A  floating  flight  for  display,  accompanied  by  alertness 
and  activity  when  alarmed,  seems  to  be  characteristic 
of  the  second  category  of  distasteful  insects  in  Mullerian 
combinations  ;  it  is  also  true  of  the  true  Heliconinae  in 
South  America,  mimics  of  the  Ithomiinae."  Again,  in 
another  letter,  written  March  6,  1912,  Professor  Poulton 
said  :  "It  is  an  extraordinarily  interesting  genus  ;  its 
habits,  I  should  think,  are  rather  like  those  of  our 
Limenitis,  and  the  degree  of  distastefulness  I  should 
think  about  the  same." 

The  genus  Pseudacraea,  therefore,  is  to  be  regarded  as 


244  PSEUDACRAEA  EURYTUS 

an  example  of  the  "  transition  from  Warning  to  Mimetic 
colours  "  described  by  Poulton  in  the  Colours  of  Animals, 
pp.  221-223,  that  is,  these  butterflies  possess  a  certain 
degree  of  distastefulness  compared  to  some  others,  but  less 
than  others  which  they  resemble,  and  so  benefit  by  the 
more  unpleasant  reputation  of  these  latter.  They  are 
Syn-aposematic  and  not  Pseud-aposematic  :  MuUerian 
and  not  Batesian  mimics. 

I  have  noticed  a  peculiar  sheen  on  the  wings,  especi- 
ally on  the  under  surface,  that  has  been  found  very 
useful  in  enabling  me  to  distinguish  the  nature  of  a 
specimen  seen  sitting  far  out  of  reach  on  a  leaf  in  the  sun. 

The  forms  with  which  we  are  concerned  in  this  chapter 
frequent  forest,  and  are  not  to  be  found  outside.  But 
flowering  shrubs  at  the  edge  of  a  forest  will  often  prove 
extremely  attractive,  so  that  Pseudacraeas  will  collect 
thereon  in  numbers,  coming  from  the  shady  forest  to 
the  bright  sun  at  the  edge,  when  they  may  be  found 
on  the  flower  heads  until  shortly  before  sunset.  On 
Bugalla  Isle,  in  1912-13,  I  had  a  favourite  walk  along 
the  edge  of  the  forest  between  4- 30-6  p.m.,  visiting  the 
gamboge  trees  [Haronga  madagascariensis),  which,  when 
in  full  bloom,  suppHed  many  fine  Pseudacraeas,  Planemas, 
and  insects  of  many  other  kinds. 

It  is  not  proposed  to  mention  here  more  than  the 
forms  of  eurytus  which  occur  in  Uganda,  together  with 
the  first  known  form,  now  known  as  eurytus  itself,  in 
West  Africa,  and  the  Eastern  and  South  African  forms. 
The  valuable  paper  by  Dr.  Karl  Jordan  at  the  first 
International  Congress  of  Entomology  ^  and  the  beauti- 
fully illustrated  book  by  Dr.  H.  Eltringham  on  African 
Mimetic  Butterflies,  will  enable  the  reader  to  gain  some 
idea  of  the  most  wonderful  polymorphism  of  this  species. 

Dr.    Jordan    (loc.    cit.)   figures    thirteen    West  African 

males   "  considered  to  belong  at  least  to  seven  distinct 

species,"    but    says    that    "as    a    result     of    my    inves- 

1  lere  Congr^a  International  d'Entomologie,  Bruxelles,  Aout,  9110, 
pp.  385-404.     Plates  zzi.-xziv. 


,..??;5  .>'*.;■  >-^.--^ 


-••^ 


PLATE   n 

1.  Plattema  aganice  form  montana  ^,  Ngamba  Island,  L. 

Victoria,  11  vii,  1914. 

2.  Psendacraea  eurytus  form  rogersi  ^  (the  type  specimen). 

Caught  by  Eev.  St.  A.  Rogers  near  Mombasa,  November,  1906. 

3.  PI.  aganice  form  montana  $  ,  Tavu  Island,  1  vii,  1914. 

4.  Ps.  eurytus  form  rogersi  ?  (the  type  specimen). 

Caught  near  Mombasa,  28  vu,  1906. 

6.  PI.  aganice  form  nyascs  ^ ,  13  vi,  13. 

Caught  by  S.  A.  Neave  on  Mt.  Mlanje,  Nyasaland. 

6.  Ps.  eurytus  form  mlanjensis  ^ ,  11  xii,  13. 

Caught  by  B.  A.  Neave  on  Mt.  Mlanje,  Nyasaland. 

7.  PL  aganice  form  nyasoe  ?  ,  10  vi,  13. 

Caught  by  S.  A.  Neave  on  Mt.  Mlanje,  Nyasaland. 

8.  Ps.  eurytus  form  mlanjensis  ?  ,  17  iii,  13. 

Caught  by  S.  A.  Neave  on  Mt.  Mlanje,  Nyasaland. 

9.  PI  aganice  3' ,  13  iv,  1897. 

Caught  by  G.  A.  K.  Marshall,  Malvern,  Natal. 

10.  Ps.  eurytus  form  imitator  c? ,  7  v,  1910. 

Bred  by  the  late  A.  D.  Millar,  near  Durban,  Natal. 

11.  PI.  aganice  ?  ,  22  iii,  1896. 

Caught  by  G.  A.  K.  Marshall,  Malvern,  Natal. 

12.  Ps.  eurytus  form  imitator  ?  ,  20  iv,  1910. 

Bred  by  the  late  A.  D,  Millar,  near  Durban,  Natal> 


m 


2il  ^ 

. ,   , ^  in  the  ' 

.s,  these  butterflie  ■ 

eiulness  compared  to  S' 

1,1 1- 1 .     ., ,   . 

...       ., n  aTAJi 

feyxi-aAjoBejnatic    aa.l    not    Pseud- aposematic  :     Arulieriaii 

.(namioeqe  sq^i  arid)  *&  h'ta^o'^  miol  ^wi^'tvsi)  jiaj>"vooS»V'a«^  ■,.8-\' 
,3061  ,iedmevoPl  .BSBcfmoM  lijon  aiogoH  .A  .i8  .79H  ^'J  iiisu^P 


S'lJ 


.^ISI  ,117  I  ,i)flBl8l  uvfiT  ,,$  jDipi«ow  miQi  ^o\««^  sS!i  .8 


,  J  .9061  .117  8S,«BBdmoM  3fl9xi  WauaO 

frequei  ,  and  are 

flowering  shrul-  '      '^^  '^^  ^.^  '"^  ^^^^"^  raionf>w»^  .Sa  .6  . 

extremely   attramj v ::V,  .-^    •■■^r.    .    .■■..■^.  ^  .•■- ....■     ■•."    ..  ..i--. 
thereon  in  nuir'^f  r^^^  ^■'■^■"  ^  ^^^m^^^  -o^^oi .  a>Ji^-vwS.  ,z^,  %8 1 r > 

.DaBlBa«i(PI  ,9J;n*IM  .JM  00  ovbqTI  .A  .Q  ^d  jJdgifBO  ^• 
the   bridv  ^^       ^^      '  ■'''■;'-'        ,«    „ 

,81  <iv  01  ,,$  joani^sr xinQj aoswftigt)  .ri  .v 

.bnjslfigBYH  ,-)[aiillli  .iM  co  av^eH  .A  .8  x:d  JrfgufiO 

.81  ,111  YI  (  2  ^V^«3\i<i)\«f  mioi  2wi\y;ma  .el  .8 
.6aeIjs8B^K  ,3[afiIM  .IM  no  . '.  .M   a  g  ^^d  ddgufiO 

itl  tui;  .IjBifiK  ,ai97lBM  .ilBjdieiBM  ./I  .A  .-d^'d  dHaufiO      ' 

and  in..     -  qjqj-  ,v  7  ^  '^  -TOh^iMuj  miol  eisi^-^ii^  ,.,5^^,  .0^  . 

It    is    not    ^BU,a&d^uaiea'a'^^^Ui^i',a'.'As'i^>\'^r^'f\j^ 

forms  of  eurytus  which  occi^^^^    U^  ,^ 

the  first  known  j|ji^  jni^T^laTte  ^li&MidiS.  .a  ,a  .i  -  va  hx^^ubj 
We?t  Africa,  anjj^j^gj-  ,,j  qj>  ^  ^  -^oJ^Vvi^^j  mioi  zwivvwa  .&^   SI 
alliabl«.lBiB>l  .aedioa  i«on  .ibUIM  ,a  .A  aisl  adi  \(d  baiQ. 


lefl«t  to  ft 
speoi' 


PLATE   II. 


Arm  fjne    rrw  <1t>]s 


V  \  ■  mp  h  aJiTie    -inimics  . 


li  C  Kivight  del.  et  chromo  |j.,^.;^-„  .j^p 

MODEL     SPECIES    OF    PLANEMA    WITH     MIMETIC    FORMS     OF 
PSEUDACRAEA    EURYTUS.  ^ncut.  size. 

ReprodjLC^  ly  perrrusstorL  of  th&  Fntornologuxcl  Soaeiy    of  LonAorv. 

(To  face-Pacfe.  24-6). 


THE    TYPE  245 

tigations  I  must  regard  these  insects  as  forms  of  only 
one  single  species,  Pseudacraea  eurytus  (Linnaeus,  1758)." 
Along  with  these  forms  of  one  species  are  figured  thirteen 
different  species  of  Planema,  each  a  model  for  a  form  of 
eurytus  ;  and  on  another  plate  "  five  white  banded  female 
specimens  of  Pseudacraea  eurytus,  together  with  the 
females  of  five  species  of  Planema.'''' 

Pseudacraea  eurytus  ^  itself  was  named  by  Linnaeus  in 
1758.  It  is  sexually  dimorphic.  The  male  is  tawny 
orange  and  blackish  brown,  the  female  black  and 
white,  with  the  white  areas  roughly  corresponding  to 
the  pattern  of  the  orange  in  the  male,  but  being  more 
contracted  on  the  hind  wing.  It  is  a  West  African  form, 
mimicking  the  West  African  dimorphic  species  Planema 
epaea.  1  have,  however,  taken  on  Bugalla  Island  a  single 
female  closely  approximating  to  the  typical  eurytus  ; 
it  is  intermediate  between  two  forms  described  below, 
namely  tirikensis  and  terra,  having  the  fore  wing  pattern 
of  terra,  but  the  black  and  white  colour  of  tirikensis,  while 
the  pattern  of  the  hind  wing  closely  approximates  to  that 
of  eurytus  and  thus  differs  from  the  pattern  of  tirikensis. 

In  1919,  in  a  small  isolated  patch  of  forest  on  the 
Kyagwe  (mainland)  north  coast  of  the  lake,  I  took  a 
fine  male  which  is  not  essentially  different  from  the 
typical  male  eurytus. 

All  the  Pseudacraeas  mentioned  in  this  chapter, 
except  kuenowi,  are  now  known  to  be  forms  of  eurytus, 
using  the  name  in  its  widest  sense.  It  has  a  distribution 
throughout  the  tropical  and  subtropical  forests  of  Africa, 
from  west  to  east,  and  from  northern  Uganda  to  Pondo- 
land,  south  of  Natal.  It  is,  however,  very  scarce  in 
East  Africa  and  Rhodesia, 

The  form  imitator  was  described  from  Natal  by  Roland 

Trimen  in    1873  :    it   mimics   Planema  aganice  and,   like 

the  model,  is  sexually  dimorphic,  although  the  difference 

in  colour  between  male  and  female  is  not  so  marked  as 

^  See  the  two  coloured  plates  for  illustrations  of  models  and  mimetic 
forms  of  this  species. 


246  PSEUDACRAEA  EURYTUS 

in  the  first  named  form.  Colonel  Bowker,  in  a  letter 
to  Trimen,  said  it  was  "  quite  impossible  to  distinguish 
between  this  butterfly  and  aganice  either  when  settled  or 
on  the  wing."     (Plate  II,  figs.  9-12.) 

The  male  and  female  have  the  same  pattern  on  a 
black  ground,  the  pattern  being  cream  coloured  in  the 
male,  while  in  the  female  it  may  be  either  cream  coloured 
or  white.  The  female  may  thus  resemble  either  the 
male  or  female  of  the  model,  which,  so  far  as  I  am  aware, 
does  not  occur  among  other  forms  of  eurytus,  in  which, 
if  the  model  is  dimorphic,  the  male  is  copied  by  the  male 
of  the  mimic  and  the  female  by  the  female.  The  white 
areas  of  the  female  differ  quite  noticeably  in  this  form 
from  the  pattern  of  the  female  eurytus,  there  being  only 
a  trace  of  white,  instead  of  a  large,  well  defined  area 
on  the  inner  margin  of  the  fore  wing.  This  species 
possesses  in  a  very  high  degree  a  most  conspicuous  aposeme 
on  the  underside  of  the  base  of  the  hind  wing  which, 
as  in  the  model,  must  be  of  great  value  when  the  insect 
is  at  complete  rest  with  the  wings  brought  together  over 
the  back.  This  aposeme  takes  the  form  of  a  well  defined 
patch  of  bright  purplish  or  reddish  brown,  extending 
outwards  from  the  base  along  the  costal  margin. 

The  form  imitator,  southern  in  distribution,  is  con- 
nected with  the  northern  forms  shortly  to  be  described 
by  forms  found  in  Nyasaland  quite  plentifully,  and  others 
more  rarely  in  East  Africa. 

Very  recently  has  been  discovered  a  single  specimen 
of  a  most  remarkably  interesting  form  which  extends 
our  knowledge  of  the  distribution  of  Pseudacraea  eurytus 
south  of  Natal  to  West  Pondoland.  The  specimen 
referred  to  is  in  the  museum  at  Tring,  and  I  am  greatly 
indebted  to  Lord  Rothschild  and  Dr.  Karl  Jordan  for 
the  loan  of  it  that  I  might  compare  it  with  others.  It 
was  taken  on  April  16,  1915,  by  H.  H.  Swinny,  at  Port 
St.  John's,  and  is  of  quite  a  distinct  reddish  orange  tint, 


A  UNIQUE   SOUTHERN   SPECIMEN         247 

which  renders  it  markedly  different  from  any  other  form 
of  eurytus  yet  known.  It  seems  to  combine  the  features 
of  the  western  eurytus  male  with  the  imitator  of  Natal. 
The  subapical  orange  area  of  the  fore  wing  is  small  and 
narrow,  as  is  the  corresponding  pale  area  of  imitator^ 
and  the  inner  marginal  area  on  the  fore  wing  is  like  that 
of  eurytus.  The  hind  wings  have  a  very  large  orange 
area  with  only  a  narrow  black  border,  as  in  the  western 
eurytus,  but  at  the  base  they  show  the  very  large  purplish 
brown  aposeme  extending  along  the  costal  margin  to 
the  tip  as  in  imitator.  This  most  interesting  specimen 
is  a  male,  and  one  awaits  the  discovery  of  its  female 
with  enthusiasm  :  probably  it  will  be  black  and  white. 
It  presumably  mimics  a  local  form  of  Planema  aganice 
which  has  yet  to  be  discovered. 

In  1904,  S.  A,  Neave  described  four  new  Pseudacraeas 
from  Uganda,  which  are  now  known  to  be  all  forms  of 
eurytus,  using  the  name  in  its  wide  sense.  The  form 
hobleyi  was  the  first  to  be  named,  and  the  others  make 
with  it  a  group  inhabiting  Uganda,  although  some  at 
least  extend  their  range  out  to  the  West  Coast.  Hobleyi 
is  a  male  form  only,  mimicking  the  male  of  Planema 
macarista.^  On  a  ground  of  blackish  brown  it  has  a  bright 
orange  bar  bent  at  an  angle,  crossing  the  fore  wing,  and 
a  white  bar  crossing  the  middle  of  the  hind  wing.  This 
latter  bar,  however,  as  in  the  model  macarista^  is  often 
bordered  with  orange-brown  and,  in  examples  brought 
by  Neave  from  Western  Uganda,  becomes  wholly  orange. 
This  form  appropriately  mimics  the  local  form  of  Planema, 
in  which  the  white  bar  of  macarista  is  replaced  by  orange. 
This  is  Planema  pseudeuryta,  very  closely  alHed  to 
macarista.  The  form  hobleyi  has  a  basal  aposeme  on 
the  under  surface  of  the  hind  wings,  but  this  differs 
sUghtly  from  that  of  imitator,  being  more  concentrated 
into  a  basal  triangle,  and  of  a  more  reddish  and  less 
1  Plate  I,  figs.  5,  6. 


248  PSEUDACRAEA   EURYTUS 

purplish  brown.  Needless  to  say,  this  aposematic  triangle 
is  a  very  marked  feature  in  the  model  macarista. 

The  shape  of  the  orange  bar  crossing  the  fore  wing 
of  hobleyi  varies  considerably,  and  in  some  cases  bears 
a  resemblance  to  the  rather  dijfferent  shape  of  the  bar 
in  a  very  different  species  of  Pseudacraea,  namely,  Ps. 
kuenowi,  which  has  the  same  general  scheme  of  colouring. 
It  seems  possible  that  these  forms  of  hobleyi  show  the 
secondary  resemblance  of  one  species  to  another,  both, 
however,  mimicking  the  same  model,  which  is  found 
and  has  been  described  by  Dr.  Dixey  and  Professor 
Poulton  in  other  combinations.  It  would  be  necessary, 
however,  before  accepting  this  for  a  fact,  to  ascertain 
whether  the  proportion  of  hobleyi  with  the  bar  like  that 
of  kuenowi  is  greater  in  the  areas  where  both  are  found 
together  than  in  areas  where  kuenowi  does  not  occur. 

Another  form  of  eurytus,  described  at  the  same  time  by 
Neave  as  a  different  species,  is  a  black  and  white  female 
known  as  tirikensis.  Later  this  was  found  to  be  the 
female  of  the  male  described  as  hobleyi,  and  the  name 
tirikensis  fell  into  abeyance.  Now,  however,  that  both 
are  known  to  be  not  a  distinct  species  but  only  forms  of 
eurytus,  the  name  tirikensis  again  holds  good  as  a  mimetic 
form  name.  This  female  form  has  a  black  ground  ;  on 
the  fore  wing  is  a  white  bar  bent  at  an  angle,  but  the 
posterior  end  of  this  beyond  the  elbow  is  often  so  suffused 
with  black  as  to  reduce  the  bar  to  a  large  subapical  area 
only.  Such  a  pattern  very  closely  resembles  that  of  the 
female  Planema  macarista,  also  found  in  Uganda  flying  with 
the  mimic.  The  hind  wing  is  black  and  white,  and  shows 
well  the  umber  triangle  at  the  base  on  the  under  side  as 
in  the  model.     (Plate  I.  figs.  7,  8.) 

This  form  is  very  variable,  and  graduates  into  others. 
Thus  a  form  from  Gaboon,  copying  the  female  Planema 
excisa,  has  the  fore  wings  like  those  of  tirikensis,  but  the 
hinder  end  of  the  white  bar  is  tinted  dull  yellow,  and  the 


FORMS   FROM   NYASALAND  249 

hind  wings  are  pale  yellowish,  approaching  those  of  such 
a  form  as  terra,  to  be  described  below. 

Another  specimen  in  the  Tring  museum,  from  Fort 
Anderson,  Nyasaland,  although  it  might  be  termed  a 
tirikensis,  has  a  much  larger  area  of  white  on  the  hind 
wing,  whereby  it  approaches  to  the  East  African  form 
rogersi,  yet  to  be  considered. 

Dr.  S.  A.  Neave  has  discovered  on  Mount  Mlanje  in 
Nyasaland  a  form  of  Planema  aganice  differing  markedly 
from  the  more  southern  Natal  form  by  the  greater  size 
of  the  pale  areas  on  all  wings  in  both  male  and  female. 
It  is  copied  closely  by  a  corresponding  form  of  Pseudacraea 
showing  the  same  differences  from  the  Natal  form,^ 
which  is  most  interesting,  for  the  shape  and  size  of  the 
subapical  white  bar  on  the  fore  wing  in  the  female  comes 
near  to  the  form  of  tirikensis  whose  white  transverse 
bar  is  suppressed  at  the  posterior  end,  while  on  the  hind 
wing  the  white  area  is  as  in  the  female  form  rogersi  of 
East  Africa,  At  the  base  of  the  hind  wing  beneath 
there  is  a  large  brown  aposematic  patch,  which  is  exactly 
intermediate  between  the  long  narrow  purplish  brown 
patch  of  the  southern  imitator  and  the  more  triangular, 
umber-brown  patch  of  tirikensis. 

This  new  form  in  Nyasaland  is  thus  beautifully  tran- 
sitional between  the  more  northern  and  the  eastern  forms 
tirikensis  and  rogersi  and  the  more  southern  imitator, 
and  agrees  as  closely  with  its  local  model  form  of  Planema 
as  do  other  Pseudacraeas  already  mentioned. 

At  the  time  when  hohleyi  and  tirikensis  were  looked 
on  as  male  and  female  of  a  distinct  species  of  Pseudacraea, 
a  very  interesting  form  was  described  by  Poulton  in 
his  paper  on  the  Wiggins  collection  ^  as  a  "  female  pos- 
sessing the  colour  and  to  a  large  extent  the  pattern 
of  the  male."  That  is  to  say,  it  has  an  angular  orange 
bar  crossing  the  fore  wing,  but  the  direction  and  shape 

1  Plate  II,  figs.  5-8. 

2  lere  Congr^s  International  d'Entomologie,   Bruxelles,   Ao<it,    1910. 


250  PSEUDACRAEA   EURYTUS 

of  the  bar  is  that  of  the  white  bar  of  the  female  form 
tirikensis  in  its  most  complete  development  :  the  colour, 
however,  is  not  the  rather  deep  orange  of  macarista,  but 
the  paler  yellowish  orange  of  the  different  species  Planema 
poggei,  of  which  both  sexes  are  alike,  and  in  which  the 
direction  of  the  orange  fore  wing  bar  is  much  more  oblique 
than  in  the  male  Planema  macarista.^  The  form  of 
Pseudacrdea  now  under  discussion  is  thus  brought  to  be 
a  mimic  of  poggei  rather  than  of  the  male  macarista  both 
in  colour  and  direction  of  the  bar  across  the  fore  wing, 
the  obliquity  being  given  to  the  bar  because  it  is  of  the 
shape  of  that  in  the  female  form  tirikensis,  and  not  of 
the  male  hobleyi. 

It  is  now  incorrect  to  speak  of  a  "  female  hobleyi 
with  male  colouring "  with  this  difference  in  shade 
in  the  orange  bar,  and  this  form  has  been  named 
poggeoides  by  Professor  Poulton.^  It  is  remarkably 
interesting  from  the  point  of  view  of  geographical 
distribution.  The  models  Planema  macarista  ^,  and 
PL  poggei  <^  ^,  occur  around  Entebbe,  but  the 
former  is  there  more  abundant  and  Pseudacraea  eurytus 
form  poggeoides  is  very  scarce,  the  females  being  almost 
all  of  the  form  tirikensis  mimicking  the  black  and  white 
female  macarista.  But  around  Mount  Elgon,  in  the 
north-east  of  Uganda,  Planema  poggei  completely  replaces 
macarista,  which  is  not  as  yet  known  to  occur  east  of 
the  Nile,  and  the  black  and  white  female  forms  tirikensis 
are  outnumbered  by  the  form  poggeoides  with  orange 
bar  across  the  fore  wing  like  the  model.'  Since  the  male 
of  the  mimic  (hobleyi)  has  the  bar  on  the  fore  wing  orange, 
the  change  in  proportion  of  the  two  model  Planemas 
does  not  affect  its  appearance. 

Thus,  in  the  case  of  the  female  forms  poggeoides  and 
tirikensis,  there  is   an  exact  parallel  to  th^  case  of  the 

1  Plate  I.  figa.  9,  10.  -  Proc.  Ent.  Soc,   1912,  p.  cxvii. 

'  Ibid.,  pp.  Ixx.-lxxi. 


FORM   TERRA  251 

male  form  hobieyi  already  discussed.  In  the  centre  of 
Uganda  a  few  forms  are  found  which,  in  the  case  of  the 
male,  become  the  predominant  form  to  the  west,  in  the 
case  of  the  female  become  the  predominant  form  to  the 
east.  In  each  case  the  alteration  between  the  proportions 
of  the  forms  coincides  with  the  different  proportions  of 
the  Planema  models  on  the  west  and  east  sides  of  Uganda. 

Another  form  that  was  described  by  Neave  in  1904 
from  the  collection  made  by  C.  A.  Wiggins  in  the  environs 
of  Entebbe  is  known  as  terra.     (Plate  I,  figs.  1,  2.) 

This  form  is  monomorphic,  male  and  female  alike 
showing  a  rich  orange  pattern  on  a  brownish-black  ground, 
mimicking  to  an  extraordinary  degree  of  perfection  the 
abundant  Planema  tellus  eumelis,  which  is  also  mono- 
morphic, although  its  West  African  form  has  a  black  and 
white  form  of  female  as  well.  The  pattern  of  the  form 
terra  is  much  like  that  of  the  male  eurytus,  save  that 
the  subapical  and  inner  marginal  orange  areas  on  the 
for£  wing  are  more  extensive  :  the  colour,  however,  is 
a  much  lighter  orange.  But  forms  of  terra  with  con- 
tracted fore  wing  areas  are  quite  common  on  the  islands, 
and  one  such,  mentioned  previously,  that  was  taken  in 
1919  on  the  Kyagwe  coast  in  an  isolated  area  of  forest, 
had  such  dark  brownish  orange  colour  that  it  was  prac- 
tically indistinguishable  from  a  typical  male  eurytus  from 
the  West  Coast.  In  terra  there  is  no  basal  aposematic 
umber-brown  triangle  on  the  under  side  of  the  hind  wing, 
and  this  is  absent  from  the  model  Planema  tellus  also. 
The  form  terra  is  found  from  Uganda  to  the  West  Coast. 

I  consider  it  to  be  the  most  perfect  mimic  of  all  the 
forms  of  eurytus  that  I  have  seen  alive  :  in  pattern  and 
colouring  it  approximates  so  closely  to  the  model  tellus 
that  I  have  been  deceived  by  it  over  and  over  again. 

On  the  islands  many  variations  have  been  found, 
showing  some  very  distinct  patterns  and  transitions  to 
other  forms.     A  common  variation  is  reduction  in  breadth 


252  PSEUDACRAEA   EURYTUS 

of  the  black  bar  separating  the  orange  areas  on  the  fore 
wing,  and  when  this  is  completely  eliminated  the  form 
described  by  K.  Griinberg  ^  as  a  distinct  species 
"  impleta  "  is  obtained.  It  would  not  require  a  great 
change  to  develop  the  male  form  of  rogersi  ^  from  impleta. 

Another  form  known  as  obscura  was  also  described 
by  Neave  in  1904,  and  is  one  of  the  group  from  Uganda 
coming  under  the  subhead  of  hobleyi.  This  is  also  a 
monomorphic  form,  male  and  female  being  alike,  as  are 
the  models,  the  eastern  form  paragea  of  Planema  epaea, 
a  common  West  Coast  Acraeine.^  The  model  is  rather 
rare,  and  the  mimic  obscura  is  also  rare.  It  has  pale 
creamy  markings,  easily  derivable  from  those  of  terra, 
but  much  smaller,  on  a  dark  greyish  brown  background. 
The  pattern  of  these  creamy  markings  does  not  follow 
so  exactly  the  pattern  of  the  model  as  does  that  of  terra, 
but  the  general  effect  is  decidedly  that  of  resemblance. 
As  regards  flight,  there  is  much  more  difference  between 
model  and  mimic  in  this  case  than  with  the  other  members 
of  the  hobleyi  group,  for  paragea  the  model  has  rather 
a  weak  fluttering  flight,  and  looks  a  feebler  insect  than 
the  robust  and  powerful  Pseudacraea.  1  have  never 
mistaken  obscura  for  its  model.  Both  show  a  certain 
amount  of  reddish  brown  at  the  base  of  the  under  surface 
of  the  hind  wing,  but  this  is  of  a  paler  tint  than  the  rich 
umber  that  makes  the  characteristic  basal  triangle  of 
hobleyi,  tirikensis,  poggeoides  and  their  models,  and  is 
not  so  sharply  defined. 

The  form  obscura  seems  to  be  the  least  fixed  of  the 
Uganda  forms  of  eurytus  comprising  the  hobleyi  group  ; 
at  any  rate,  on  the  islands  it  was  quite  difficult  to  obtain 
two  that  were  closely  alike  and  did  not  show  transition 
to  one  of  the  other  forms. 

Lastly,  there  is  the  extremely  rare  and  little  known 
form  from  near  Mombasa,  British  East  Africa,  described 

^  Sitzungsber.  d.  Oes.  NaturJ.  Freunde,  Nr.  4,   1910. 
2  Plate  II,  fig.  2.  3  Plate  I,  fig3.  3,  4. 


FORM   ROGERSI  253 

as  rogersi  after  its  captor,  by  Trimen  in  1908.^  The  form 
is  dimorphic,  the  male  having  the  wings  blackish  brown 
and  orange,  but  the  orange  is  of  a  slightly  more  reddish 
tint  than  in  other  forms,  and  approaches  the  hue  of  the 
unique  specimen  previously  mentioned  from  West  Pondo- 
land.  There  is  an  irregular  area  on  the  fore  wing  like 
that  in  some  of  the  varieties  of  terra  in  which  the  black 
bar  is  broken  through. 

The  black  and  white  female  has  a  pattern  after  the 
style  of  the  typical  female  of  the  western  eurytus,  except 
that  the  white  area  on  the  hind  wing  is  very  much  larger, 
and  sharply  outlined  by  a  narrow  black  border.  There 
is  a  certain  amount  of  reddish  suffusion  on  the  under 
surface  of  the  base  of  the  hind  wing. 

This  form,  rogersi,  is  represented  in  collections  by  a 
single  male  and  female  at  Oxford,  the  types.  When  I 
was  recently  looking  through  Lord  Rothschild's  magni- 
ficent collection  of  Pseudacraea  eurytus  at  Tring,  I  found 
there  were  three  females  bearing  labels  "  Mombasa  " 
that  appear  to  be  of  this  form,  but  I  do  not  know  of  any 
other  males. 

The  only  Planema  of  abundance  in  the  locality  from 
which  this  form  is  known  is  Planema  aganice,  in  its 
eastern  and  northern  form  montana?  In  this  form  the 
sexes  are  different  and  much  more  unlike  than  those 
of  the  southern  aganice  ^  which,  be  it  remembered,  served 
as  model  in  Natal  for  the  form  of  Pseudacraea  eurytus 
known  as  imitator.  In  aganice  montana  the  male,  instead 
of  having  a  creamy  yellow  pattern,  has  the  same  areas 
of  a  rich  orange.  In  the  form  rogersi  now  under  dis- 
cussion, the  pattern  is  not  quite  like  that  of  Planema 
aganice  montana,  and  is  much  nearer  that  of  another 
species  of  East  African  Planema,  viz.  adrasta.  This 
species  has,  in  the  male,  a  complete  orange  bar  across 
the  fore  wing,  and  the  female  has  the  very  large  sharply 
marked    white    area   on    the    hind    wing.     Specimens    of 

1  Plate  II,  figa.  2,  4.      «  Plato  II,  iSga.  1,  3,      »  Plate  II,  figs.  9,  11. 


254 


PSEUDACRAEA  EURYTUS 


adrasta  in  the  Tring  museum  come  from  Usambara,  but 
it  appears  at  present  too  rare  to  be  claimed  as  a  model 
for  rogersi,  although  the  latter  resembles  it  much  more 
closely  than  it  does  montana.  In  colouring,  however, 
the  male  rogersi  approaches  closely  enough  to  the  male 
of  its  model,  and  the  black  and  white  female  is  a  close 
mimic  of  the  female  aganice  montana. 

The  following  table  shows  at  a  glance  the  models  and 
mimics  hitherto  dealt  with,  arranged  in  geographical  order 
from  the  west  to  the  east  coast  and  then  southwards,  each 
type  of  colouring  and  pattern  having  a  row  to  itself. 


Species  of  Planema. 


(?  ? 


epaea  (J 
epaea  $ 
tellus  eumelis 
macarista  (J 
macarista  ? 
macarista  pscud- 

euryta  (J 
epaea  paragea  ^  ? 
poggei  cj  $ 


9.  aganice  tnontana  ^ 

10.  aganice  montana  $ 

1 1 .  aganice  nyasce.  •  cJ 

12.  aganice  nyasce  ^  ? 

13.  aganice  ^ 

14.  aganice  $ 
16.  aganice  ^  (?) 


Forms  of  Pseudacraea 
eurytus. 


eurytus  (J 
eurytus  $ 
terra  (J  ? 
kobleyi  (J 
tirikenais  $ 
form  of  hobleyi  ^ 

obscura  <J  ? 
poggeaides  $ 

rogersi  ^ 
rogersi  $ 
mlanjensis  (J 
mlanjensis  $ 
imitator  cJ 
imitator  ? 
form  of  imitator  ^ 


Distribution  (roughly) 


W.  Africa 

W.  Africa 

W.  coast  to  Uganda 

W.  coast  to  Uganda 

W.  coast  to  Uganda 

W.  border  of  Uganda 

Uganda 

Uganda,    especiallyto 

its  E. 
Mombasa,  E.  coast 
Mombasa,  E.  coast 
Mt.  Mlanje,  Nyasaland 
Mt.Mlanje,  Nyasaland 
Natal 
Natal 
W.  Pondoland 


We  have  here  fifteen  forms  of  one  species  of  Pseudacrdea 
mimicking  eight  different  species  or  subspecies  of  Planema. 
Specific  names  were  also  given  in  the  past  to  a  large 
number  of  other  forms  of  Pseudacraea  eurytus  on  the 
west  coast  of  Africa  differing  from  the  above,  although 
easily  derivable  from  them  by  transitional  varieties 
known   to   exist,    and   these   bear   equally   close   mimetic 

*  The    names  nyasce  and  mlanjensis  have  been  chosen    to   distinguish 
these  geographical  races  of  model  and  mimic. 


EARLY  EVIDENCE  OF  CONSPECIFITY      255 

resemblance  to  different  species  of  West  African  Planemti. 
(See  Dr.  Jordan's  paper,  already  cited.) 

It  will  be  interesting  now  to  trace  the  development 
of  our  knowledge  of  this  most  fascinating  polymorphic 
species. 

Professor  Poulton,  in  a  letter  to  Nature,  August  28, 
1912,  stated  :  "A  little  more  than  two  years  ago  Dr. 
Karl  Jordan  informed  me  that  he  had  been  studying 
the  male  genital  armature  of  the  Pseudacraeas,  and  that 
he  could  not  find  any  difference  between  the  '  species  * 
of  a  large  group  made  up  of  Linne's  eurytus  and  its 
numerous  allies  on  the  West  Coast,  of  Neave's  hobleyi 
terra  and  obscura  in  Uganda,  of  Trimen's  rogersi  of  the 
Mombasa  district  and  his  imitator  of  Natal." 

The  provisional  conclusion  drawn  from  this  fact  was 
that  these  butterflies  are  conspecific,  and  this  was  brought 
before  the  first  International  Congress  of  Entomology 
at  Brussels  by  Dr.  Jordan  in  August  1910. 

At  the  same  congress  Professor  Poulton  gave  a  statis- 
tical study  of  the  large  collection  made  near  Entebbe  in 
Uganda  by  Dr.  C.  A.  Wiggins,  and  stated  that  in  this 
were  two  specimens  which  tended  to  confirm  Jordan's 
anatomical  findings.  One  was  "  a  male  Ps.  terra  with 
a  pattern  approaching  the  male  of  Ps.  hobleyi,'^  the 
other  "  a  female  Ps.  hobleyi  bearing  the  mimetic  colours 
of  its  own  male  "  (this  is  the  form  now  known  as 
foggeoides).     (Plate  I,  fig.   10.) 

Quotations  from  letters  that  I  received  from  Professor 
Poulton  after  work  was  commenced  on  the  islands  in  1911 
will  show  how  keenly  interested  he  was  in  the  problem, 
and  how  important  he  considered  it. 

I  first  met  with  Psevdacraea  eurytus  on  Damba  Island 
in  1911,  towards  the  end  of  my  stay  there,  and,  not  know- 
ing anything  about  it,  found  this  mimetic  butterfly  very 
puzzling.  Not  only  was  it  difficult  at  first  to  distinguish 
the  forms  from  their  models,  but  they  showed  such  varia- 


256  PSEUDACRAEA  EURYTUS 

tion  that  it  was  difficult  to  assign  specimens  to  any 
particular  form,  for  a  single  specimen  often  appeared  to 
be  transitional  between  terra,  hohleyi  and  obscura.  The 
model  species  of  Planema  were  extremely  scarce  on 
Damba,  and  this  point  proved  to  be  of  great  significance. 

A  letter  from  Professor  Poulton,  dated  October  30,  1911, 
referring  to  the  arrival  at  Oxford  of  the  first  consignment 
of  these  intermediate  Pseudacraeas,  said  :  "  They  looked 
most  interesting,  and  perhaps  here  your  island  forms 
will  be  different  and  throw  light  on  the  polymorphism 
of  this  set  of  forms." 

November  9,  1911. — "  You  have  the  Pseudacraeas  abun- 
dantly evidently,  and  it  is  of  the  utmost  importance 
to  breed  them  from  known  parents.  They  tend  to  be 
far  more  intermediate  than  on  the  mainland.  I  suspect 
that  selection  of  them  is  somewhat  relaxed  on  the  island, 
and  they  at  once  tend  to  mix.  You  have  terra  and 
hohleyi  ?  (I've  not  seen  <?  yet)  and  another  form, 
obscura,  and  transitions  of  the  most  beautiful  kind 
between  obscura  and  terra,  and  between  obscura  and 
hohleyi  ?  .  I've  only  seen  now  among  your  specimens 
the  models  of  hohleyi  {Planema  macarista  3'  and  ?  and 
PL  poggei),  but  no  models  as  yet  of  the  other  two  {terra 
and  obscura).  Now  if  these  models  are  rare  or  absent 
perhaps  we  have  the  cause  of  the  varieties  of  obscura 
and  terra,  viz.  a  consequence  of  freedom  from  rigid 
selection.  It  is  an  exciting  problem,  and  you  are 
evidently  in  a  most  interesting  locality." 

November  12,  1911. — "This  is  the  exciting  thing; 
there  is  no  doubt  that  the  Pseudacraeas  tend  to  lose  their 
distinctness  in  the  absence,  or  rarity,  of  their  models. 
It  is  most  interesting  and  entirely  supports  Dr.  Jordan's 
views.     I  cannot  tell  you  how  pleased  I  am." 

These  specimens  from  Damba  Island  were  exhibited 
at  a  meeting  of  the  Entomological  Society  of  London  on 
December  6,  1911,  by  Professor  Poulton,  who  said: 


EARLY  CAPTURES   ON   DAMBA   ISLE       257 

"  I  suggest  that,  in  an  area  where  these  mimetic 
patterns  are  less  strongly  selected,  there  is  a  tendency, 
checked  elsewhere,  for  them  to  run  into  each  other,  and 
also  to  move  in  the  direction  of  the  western  eurytus 
forms,  from  which  there  can  be  little  doubt  that  the 
mimetic  Pseudacraeas  of  Uganda  originally  developed. 
It  is  to  be  hoped  that  Dr.  Carpenter  may  be  able  to 
obtain  the  material  by  breeding,  as  well  as  by  capture, 
by  which  this  hypothesis  will  be  confirmed  or  refuted."  ^ 

The  following  table  gives  at  a  glance  the  forms  and 
varieties  of  eurytus,  with  their  models,  that  were  taken 
on  Damba  : 


Models. 

Planema  poggei    . . 
„         macariata 
„         epaea  paragea . 
„         tellus  ewnelia  . 

Models 


16 


Mimetic  fonna  of  eurytus. 

poggeoides      . .      . .  —        1 

hobleyi 5        — 

tirikensis       . .      . .  —        4 

obscura 2         1 

terra       6         9 

Mimics 28 

Intermediates        . .  10 

Total  eurytus         . .         38 


It  is  seen  that  the  mimics  are  almost  twice  as  numerous 
as  the  models,  and  there  are  in  addition  more  than  one- 
third  again  of  forms  intermediate  between  the  mimics. 
The  total  number  of  Pseudacraeas  is  more  than  twice 
that  of  the  Planemas.  Concerning  these  specimens  Pro- 
fessor Poulton  wrote  January  1,  1912  :  **  I  am  most  inter- 
ested to  hear  that  you  did  not  distinguish  the  Planemas 
and  Pseudacraeas  (I  do  not  wonder  at  it)  :  it  makes  the 
results  more  conclusive.  There  must  be,  I  conclude  and 
argue  in  this  little  paper,  something  unfavourable  to 
Planemas  in  the  conditions  of  Damba  Islands  ;  and  in 
their  absence  or  scarcity  selection  is  damped  down  and 

^  Proc.  Ent,  Soc,  1911,  p.  xciv. 
18 


258  PSEUDACRAEA   EURYTUS 

the  forms  are  beginning  to  run  into  each  other  and  also 
to  assume  entirely  different  proportions  from  those  of  the 
mainland.     It  is  most  interesting  and  indeed  exciting." 

Early  in  1912  I  moved  camp  to  the  north-east  corner 
of  Bugalla  Island,  the  largest  of  the  Sesse  archipelago  in 
the  north-west  corner  of  the  Lake.  The  north-west 
promontory  of  this  island  almost  touches  the  mainland 
coastline  at  the  port  of  Bukakata  (see  map). 

It  very  soon  became  apparent  that  all  the  combinations 
which  were  of  so  great  interest  at  Entebbe  and  on  Damba 
Island  were  present  here,  and  on  March  16,  1912,  Pro- 
fessor Poulton  wrote  : 

"  I  am  very  glad  that  Sesse  is  turning  out  to  be  so 
interesting,  and  I  quite  think  now  that  it  will  be  even 
more  interesting  to  compare  these  two  groups  of  islands 
together  rather  than  to  get  evidence  from  only  one.  You 
will  realize  the  utmost  importance  of  catching  all  the 
models  and  mimics  you  can  secure  on  given  days  without 
any  selection,  so  that  we  can  estimate  the  proportions 
of  models  and  mimics  and  see  whether,  as  in  Damba, 
the  mimics  are  relatively  far  more  abundant  than  on  the 
mainland,  and  whether,  as  also  in  Damba,  the  inter- 
mediates are  specially  prevalent. 

If  the  results  in  Damba  are  supported  by  a  large  col- 
lection on  Sesse,  I  think  the  matter  will  really  be  estab- 
lished, and  will  constitute  the  strongest  argument  I 
know  for  the  origin  and  maintenance  of  mimicry  by 
natural  selection  ;  for  directly  the  models  are  reduced 
the  mimics  begin  to  run  into  each  other.  I  think,  in 
your  case,  when  you  are  necessarily  pressed  with  other 
work,  that  it  would  be  best  to  concentrate  attention  on 
the  most  important  problems,  and  those  certainly  are 
the  proportions  of  models  and  mimics  and  the  compo- 
sition of  the  mimetic  Pseudacraea  group,  and  breeding 
the  latter  to  prove  that  they  are  all  one." 

April    6,    1912. — "  How  splendid  that  the  problem  is 


VARIOUS  FORMS  COURT  EACH  OTHER  259 

more  illuminated  at  Sesse  than  Damba.  I  never  thought 
that  I  should  get  such  evidence  of  the  effect  of  a  model 
on  its  mimic,  ...  It  is  very  important  that  the  Wiggins 
Pseudacraea  mimics  come  from  several  localities  near 
Entebbe  and  yet  never  approach  your  island  forms  in 
being  intermediate,  or  resemble  their  proportions  to  each 
other  or  to  the  models." 

I  began  to  try  to  obtain  ova  from  captured  females 
placed  in  a  box  in  the  ft>rest,  but  although  I  knew  the 
genus  of  tree  on  which  they  would  probably  oviposit 
{Chrysophyllum,  Sapotaceae),  it  was  some  time  before  I 
discovered  it  in  the  forest.  It  may  be  said  here  that 
Miss  Fountaine  has  published  ^  beautifully  coloured  draw- 
ings of  the  early  stages  of  the  form  imitator,  which  is  the 
only  representative  in  Natal. 

But  breeding  this  form  has  thrown  no  light  on  its 
genesis,  or  on  the  other  forms.  For,  since  there  is  only 
one  Planema  to  act  as  a  model,  imitator  appears  to  have 
become  more  fixed  than  the  forms  of  hobleyi  in  Uganda, 
and  varies  very  little. 

Meanwhile,  I  had  often  seen  the  various  forms  in 
Uganda  flirting  with  each  other  in  the  manner  character- 
istic of  male  and  female  of  the  same  species.  The  follow- 
ing letter  to  Professor  Poulton  is  quoted  from  the  Proc. 
Ent.  Soc,  June  5,  1912,  p.  Ixxxv  :  "I  have  already  told 
you  that  I  have  seen  male  hobleyi  flirting  with  female 
terra  and  vice  versa,  both  hovering  flutteringly  in  the 
air.  Since  then  I  have  seen  a  male  obscura  paying  court 
to  a  female  terra  in  the  same  way.  This  makes  the 
observations  complete.  ...  So  far  I  have  not  succeeded 
in  getting  eggs,  though  I  have  kept  four  females  full 
of  ova  :  three  have  died  without  result,  the  fourth  I 
have  had  for  a  week  and  it  is  still  living,  though  it  has 
hardly  any  wings  left." 

However,    prolonged    observation    in    the    forests    at 
.     1  Trans.  Ent.  Soc,  1911,  pp.  57-9. 


260  PSEUDACRAEA  EURYTUS 

length  met  with  success,  as  told  in  a  letter  dated  June 
16th  (and  partially  printed  in  the  Proc.  Ent.  Soc,  1912, 
p.  cxv)  : 

"  I  feel  I  can  almost  say,  as  did  Charles  Kingsley, 
'  At  last  !  '  To-day  (Sunday)  being  a  sunny  morning 
after  many  wet  mornings,  I  went  butterflying.  I  saw 
a  few  freshly  emerged  Pseudacraeas,  and,  just  as  I  was 
coming  away,  saw  a  beautiful  obscura,  whose  very  large 
pale  areas  indicated  more  than  a  touch  of  the  female 
hohleyi.  It  was  fluttering  about  from  bush  to  bush, 
and  was  too  shy  to  let  me  get  near  to  catch  it.  At  last 
it  settled,  and  hung  from  the  underside  of  a  leaf,  and  I 
was  able  to  see  it  had  a  fairly  distinct  basal  triangle 
(indicating  admixture  with  the  form  hohleyi).  It  remained 
motionless  a  few  seconds,  and  though  that  attitude  is 
exceptional  for  Pseudacraea  (they  always  rest  on  the 
upper  side  of  a  leaf  with  wings  usually  expanded)  it  never 
struck  me  what  was  up.  I  tried  to  catch  it,  but  it  flew 
off  before  I  got  within  striking  distance.  It  then  occurred 
to  me  to  look  at  the  leaf,  and  to  my  inexpressible  joy 
and  excitement,  there  was  a  freshly  laid  egg  on  the  middle 
of  the  under  surface,  still  moist  with  the  secretion  which 
fastened  it  to  the  leaf.  So,  if  this  egg  produces  a  terra 
(and  the  chances  are  in  favour  of  this,  as  terra  is  much 
the  commonest  here),  you  will  have  the  proof  you  so 
ardently  desire,  seeing  that  the  parent  was  a  mixture 
of  hohleyi  and  ohscura  !  Anyhow,  now  that  I  know  and 
have  found  the  food  plant,  I  may  have  better  luck  in 
getting  a  captive  Pseudacraea  to  lay.  There  is  just  time 
for  the  egg,  larva,  and  pupa  to  develop  before  the  con- 
gress at  Oxford  is  over,  so  that,  should  the  offspring  be 
terra  or  hohleyi  I  will  let  you  know.  As  of  course  there  will 
be  no  time  to  write,  I  will  cable  just  the  one  word,  either 
terra  or  hohleyi.  If  it  is  ohscura  I  will  not  cable,  but 
will,  of  course,  write.  I  feel  that  it  will  be  such  a  splendid 
opportunity    for    making    this    result    known    when    you 


PROOF  BY  BREEDING  261 

will  be  showing  the  Pseudacraeas  with  special  intent  to 
prove  their  conspecificity  by  the  intermediate  forms." 

This  egg,  whose  development  is  fully  recorded  else- 
where,^  with  descriptions  of  the  larva  at  different  stages 
(which  I  dubbed  "  Toby,"  feeling  that  he  was  important 
enough  to  deserve  a  name  !)  and  of  the  pupa,  eventually, 
on  August  16th,  became  a  butterfly  of  the  form  terra, 
somewhat  transitional  to  obscura.  Thus  was  obtained  the 
first  proof  by  breeding  that  the  forms  of  eurytus  known 
as  tirikensis,  hobleyi,  terra  and  obscura  are  conspecific. 
The  cable  bearing  the  single  word  "  terra,^^  probably  the 
first  cable  ever  sent  about  a  butterfly  only,  did  not  reach 
Oxford  until  after  the  conclusion  of  the  Entomological 
Congress,  but  Professor  Poulton  announced  the  result 
in  the  letter  to  Nature  (September  12,  1912,  p.  36),  which 
has  been  already  partially  quoted. 

A  letter  that  I  received  from  him  may  be  quoted  here. 

August  19,  1912. — "  I  must  write  at  once  now  that 
the  great  cable  has  come  to-day.  I  will  send  a  letter 
to  Nature  next  week,  so  that  you  may  get  the  credit  at 
once  of  this  most  important  discovery.  .  .  . 

"It  is  splendid  to  have  this  great  disturbing  question 
settled  at  last.  Your  work  is  a  splendid  help  towards 
confirming  the  Darwinian  theory  of  mimicry.  ...  I 
must  now  conclude,  but  cannot  do  so  without  again  con- 
gratulating you  on  this  great  success.  I  have  longed 
for  this  to  be  done  for  two  or  three  years,  and  have  tried 
my  best  to  induce  friends  to  do  it.  I  even  tried  to  persuade 
Millar  to  journey  from  Durban  on  purpose  to  do  it  ! 
It  is  a  splendid  thing  to  have  accomplished  ;  quite  side 
by  side  with  Marshall's  breeding  of  the  seasonal  forms 
of  Precis.^  .  .   . 

"  P.S. — After  your  cable  I  imitated  your  example 
and    have    just    had    a    sleepless    night  !     But    it's    only 

1  Trans.  Ent.  Soc,   1912,  pp.   706-11. 

2  Ibid.,  1902,  pp.  417-58, 


262  PSEUDACRAEA   EURYTUS 

natural,  and   to   be  expected  after  such  exciting  intelli- 
gence." 

Again,  on  October  26,  1912,  Professor  Poulton  wrote  : 
**  I  am  glad  that  you  are  realizing  the  great  importance 
of  this  material  as  a  test  for  Natural  Selection  against 
Mutation.  It  seems  almost  too  good  to  be  true.  ..." 
On  November  22,  1912,  he  again  wrote  : 
"I  do  not  doubt  that  imitator  in  Natal  is  just  as 
successful  as  eurytus  on  the  West  Coast.  Probably 
nowhere  in  Africa  are  Pseudacraeas  quite  as  successful 
as  they  are  in  Uganda.  But  on  the  West  Coast  they 
are  very  polymorphic,  in  Natal  monomorphic,  yet  both 
about  equally  successful.  I  take  it  that  any  variety  in 
Natal  that  might  lead  on  to  a  new  form  is  at  once  exter- 
minated because  there  is  only  one  Planema  there,  namely 
aganice,  but  on  the  West  Coast  there  are  many  models, 
and  any  variety  leading  to  one  of  them  causes  the  varia- 
tion to  fall  into  the  surviving  percentage.  If  that  model 
disappeared  the  form  would  then  drop  out.  We  get  all 
this  happening  round  Entebbe  according  as  the  models 
change  or  disappear  "  (e.g.  the  change  in  hohleyi  from  white 
banded  to  brown  banded  hind  wing,  and  of  the  female 
from  tirikensis  to  poggeoides  in  different  proportions  in 
different  parts  of  Uganda).  "  Only  to-day  I  saw  the  male 
hohleyi  from  Neave's  Western  Uganda  series  with  a  brown 
bar  crossing  the  hind  wing,  and  in  the  same  lot  was  the 
Planema,  a  form  of  macarista  with  a  similar  male."  (This 
form  is  known  as  pseudeuryta,  and  has  been  already 
alluded  to.) 

"I  do  not  believe  that  any  of  these  mimics  depend 
for  their  existence  on  the  model.  The  pattern  depends 
for  its  existence  on  the  model,  but  not  the  species  which 
produces  the  j)attern.  That  is  to  say,  Pseudacraea 
eurytus  is  a  species  which  could  stand  by  itself,  and  indeed 
does  so  on  certain  islands  where  the  protection  afforded 
by     Planema    models    is    non-existent,    but    the    form 


FAMILIES   REARED  263 

in  which  it  appears  is  influenced  by  the  varying  pro- 
portions of  these  models.  Reasons  have  already  been 
given  for  regarding  eurytus  as  a  species  at  least  partially 
protected." 

On  November  23,  1912,  Professor  Poulton  writes 
again  : 

"  The  non-variation  of  imitator  seems  to  me  quite 
explicable  by  selection,  for  in  its  locality  there  is  only 
one  Planema.  Rogersi  may  be  looked  upon  as  the  con- 
necting link  between  Uganda  and  Natal,  and  I  have  not 
the  least  doubt  that  there  are  plenty  of  Pseudacraeas  in 
British  East  Africa  and  further  south,  but  they  are  mis- 
taken for  Planema  by  collectors.  ...  I  have  no  doubt 
you  are  right  about  hobleyi  being  the  most  distinct  form  ; 
that  it  should  keep  its  sexual  dimorphism  so  clearly  is 
further  evidence  of  this,  and  I  should  suspect  it  does 
follow  the  Mendelian  relationship  to  one  or  both  of  the 
others.  It  would  be  very  interesting  if  this  could  be 
tested  :  the  main  reason  against  it  is  the  very  great 
abundance  of  intermediates.  For  this  reason  I  should 
very  much  doubt  a  Mendelian  relationship  between 
terra  and  obscura." 

Since  "  Toby  "  was  reared  I  have  been  fortunate  enough 
to  obtain  eggs  from  females  kept  in  captivity.  They 
were  put  with  branches  of  the  Chrysophyllum  into  a  large 
wooden  box  whose  sides  and  top  had  been  partially 
replaced  by  mosquito  net.  The  box  was  placed  on  tins 
standing  in  water  in  a  large  basin  which  stood  on  a  fallen 
tree  trunk  in  a  small  open  place  where  gleams  of  sun- 
shine could  penetrate  into  the  cage.  I  had  no  success 
unless  the  butterfly  was  kept  in  the  forest,  since  the 
species  seems  to  be  easily  killed  by  the  less  humid  atmo- 
sphere outside  the  forest,  and  the  greater  heat.  Several 
small  families  were  reared  from  known  mothers,  and 
may  be  seen  with  the  parents  in  the  Hope  collection  at 
Oxford. 


264 


PSEUDACRAEA  EURYTUS 


Family. 

9  Parent. 

Offspring. 

1 

obscura  -tirikensis 

1 .  ?  terra-tirikensis 

2.  ?  obscura-tirikensis 

3.  ?  terra-tirikensis 

2 

obscura 

1.  (J  obscura-terra 

3 

obscura-tirikensis 

1.  $  terra-tirikensis 

2.  ?  terra-obscura 

3.  ?  terra-tirikensis 

4.  ?  terra-obscura 

5.  c?  obscura-terra 

6.  ?  o6scMro-<erra 

7.  c?  obscura-tcrra 

4 

tirikensis 

1.  ?  tirikensis 

2.  (J  }iobleyi-terra-obsc\ 

3.  $  obscura-tirikensis 

5 

terra 

1.  cj  terra-hobleyi 

6 

tirikensis 

1.  $  tirikensis 

2.  cj  hobleyi 

3.  ?  tirikensis 

4.  9  tirikensis 

5.  ?  tirikensis 

6.  $  tirikensis 

7 

tirikensis 

1.  (J  obscura-terra 

2.  cj  obscura-terra 

3.  (?  hobleyi 

4.  $  obscura 

5.  (?  obscura-terra 

6.  c?  obscura-terra 

7.  (^  hobleyi 

8.  9  obscura 

8 

terra-tirikensia 

1.  (?  terra-hobleyi 

It  seems  as  if  the  forms  hobleyi  and  tirikensis  were 
predominant  over  the  other  two,  for  although  ^ena  and 
obscura  tainted  with  hobleyi  or  tirikensis  abound  (as  shown 
by  the  umbre  triangle  at  the  base  of  the  hind  wing),  yet 
I  have  never  seen  a  specimen  that  could  be  described 
as  hobleyi  tainted  with  ^erra  or  obscura.  So  far,  <ena 
or  obscura  untainted  with  hobleyi  or  tirikensis  have  not 
been  bred  from  tirikensis  parent,  and  one  of  the  most 
abundant  intermediate  forms  is  ferra  with  more  or  less 


MODELS,  MIMICS   AND   INTERMEDIATES    265 


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266  PSEUDACRAEA  EURYTUS 

of  the  basal  umbre  indicating  influence  by  hohleyi  or  its 
female  tirikensis.  It  would  seem  as  if  hohleyi  and  tiri- 
Tcensis  are  the  strongest  and  most  stable  forms,  influencing 
the  other  two. 

These  abundant  forms  of  Pseudacraea  eurytus  that 
have  been  captured  on  the  islands  of  Lake  Victoria  have 
a  very  important  bearing  on  the  explanation  of  mimicry 
by  Natural  Selection.  As  is  abundantly  evident  from 
letters  quoted,  Professor  Poulton  believes  that  here  is 
strong  evidence  of  the  efficacy  of  Natural  Selection  in 
at  least  keeping  the  mimics  up  to  the  mark.  When  models 
are  scarce  no  one  form  of  Pseudacraea  has  any  particular 
survival  value  over  another,  and  all  kinds  of  non-mimetic 
transitional  forms  are  preserved  which,  when  the  models 
are  superabundant,  are  presumably  destroyed  by  enemies 
so  that  they  do  not  appear  in  collections. 

It  would  be  of  the  very  greatest  interest  at  the  present 
time  to  obtain  offspring  from  the  mimetic  forms  on  the 
mainland  and  ascertain  whether  they  will  produce  transi- 
tional offspring.  Indeed,  we  know  that  they  do  produce 
a  certain  proportion  of  these,  for  two  examples  have 
been  captured  at  Entebbe  and  have  been  alluded  to 
before. 

The  table  on  p.  265  shows  by  comparison  the  difference 
between  collections  made  without  prejudice  at  localities 
where  Planema  outnumbers  Pseudacraea,  and  where  the 
latter  are  predominant. 

The  chart  on  p.  267  shows  very  graphically  how  the 
figures  vary  and  the  manner  in  which  the  numbers  of 
Planemas  and  of  intermediate  Pseudacraeas  vary  inversely. 

A  most  remarkable  thing  is  the  complete  change  in 
the  proportion  of  Planema  to  Pseudacraea  on  Kome 
Island  and  its  near  neighbours  to  the  west  in  the  period 
between  1914  and  the  end  of  1918  and  commencement 
of  1919.  When  I  was  on  Kome  for  several  months  in 
1914,    Planemas    far   outnumbered   Pseudacraeas,    which 


MODELS,   MIMICS   AND   INTERMEDIATES    267 

showed  very  little  variation,  as  may  be  seen  from  the 
table. 

But  to  my  great  astonishment,  when  I  returned  to 
the  same  islands  after  the  war,  the  situation  had  been 
completely  reversed,  and  the  Pseudacraeas,  which  showed 
much  variation,  greatly  outnumbered  the  Planemas 
(see  table,  p.  265).  It  must  be  supposed  that  the 
Planemas  had  been  found  at  the  summit  of  a  wave  of 
prosperity  in  1914,  but  that  their  enemies  (possibly 
parasites)  had  increased  so  greatly  that  they  in  turn 
reached  the  summit  of  a  wave  while  the  Planemas  fell 


Proportion  of 
Planemas  in  file 
tot^l  captures 
of  Butterflies. 

90 

80 
70 

Entebbe 
1909 

bamba  1^ 
1911 

Bugallals 
191  i  •  13 

Kome  group 
1914 

Kakindu. 
1915 

Komegroup 

1918- 19 

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intermediate 
to  total  number 
of  Pseudacraeas 

50 
20 
10 

y 

^-. 

^ 

/ 

^ 

• 

into  a  trough.  This  would  be  analogous  to  what  is  known 
to  happen  in  England  in  the  case  of  the  Hop  Aphis  and 
the  Ladybirds  which  feed  upon  them,  each  in  turn 
fluctuating   in   number. 

It  is  most  interesting  to  note  how  the  Pseudacraeas 
changed  in  constancy,  the  intermediate  forms  having 
been  apparently  destroyed  while  the  models  exercised 
their  protection  to  the  mimetic  forms  in  1914,  but 
having  an  equal  chance  of  survival  in  1918-19  when 
the  protection  of  the  models  was  in  abeyance.  Young 
birds    in    1914    had    a    different    lesson    to    learn    from 


268  PSEUDACRAEA   EURYTUS 

those  of  1918-19  ;  and  also  those  that  had  learnt  their 
lesson  in  1914  must  be  supposed  to  have  unlearnt  it  in 
1918,  when  the  models  which  they  had  known  to  be 
distasteful  were  no  longer  to  be  seen.  If  this  be  so,  then 
it  must  be  further  supposed  that  birds  need  to  refresh 
their  memories  at  intervals  during  adult  life. 

These  numerous  and  beautifully  graded  transitional 
forms  of  one  species  are  quite  consistent  with  the  explan- 
ation of  mimicry  being  produced  and  maintained  by 
the  continuous  operation  of  Natural  Selection  upon  small 
variations. 

But  at  first  sight  they  do  not  seem  to  be  at  all  in  con- 
formity with  the  theory  of  the  production  of  mimics  by 
Mutations — that  is,  sudden  large  variations  which  appear 
complete  all  at  once  and  never  revert  to  the  form  of  the 
parent.  Indeed,  the  writings  of  such  an  exponent  of 
the  Mutation  theory  as  Professor  Punnett  seem  at  first 
sight  to  support  this  argument,  that  the  intermediates 
are  a  difficulty  in  the  way  of  the  Mutationist. 

Thus,  in  the  5th  edition  of  Mendelism,  1919,  he  dis- 
cusses two  forms  of  an  interesting  species  of  Euralia,  a 
Nymphaline  of  which  the  form  wahlbergi  mimics  Amauris 
niavius  dominicanus,  and  the  form  mima  mimics  Amauris 
echeria.  On  p.  177  Professor  Punnett  says:  "According 
to  Mendelian  views,  on  the  other  hand,  the  dominicanus 
pattern  arose  suddenly  from  the  echeria  pattern  (or  vice 
versa),  and  similarly  wahlbergi  arose  suddenly  from  mima. 
.  .  .  On  the  modern  Darwinian  view  natural  selection 
gradually  shapes  mima  into  the  wahlbergi  form  owing  to 
the  presence  of  dominicanus ;  on  the  Mendelian  view 
natural  selection  merely  conserves  the  wahlbergi  form 
when  once  it  has  arisen.  Now  this  case  of  mimicry  is 
one  of  especial  interest,  because  we  have  experimental 
evidence  that  the  relation  between  mima  and  wahlbergi 
is  a  simple  Mendelian  one,  mima  here  being  the  dominant 
and  wahlbergi  the   recessive  form.     The   two  have   been 


INTERMEDIATES   AND   MUTATION  THEORY     2G9 

proved  to  occur  in  families  bred  from  the  same  female 
without  the  occurrence  of  any  intermediates,  and  the 
fact  that  the  two  segregate  cleanly  is  strong  evidence  in 
favour  of  the  Mendelian  view." 

In  the  case  of  the  theoretical  origin  of  wahlbergi  from 
mima  the  change  in  pattern  is  a  large  one,  and  it  may 
well  be  asked  what  are  the  chances  against  the  proba- 
bility of  the  dominicanus-wahlbergi  pattern  arising  sud- 
denly, complete,  in  two  cases,  from  the  very  different 
echeria-mima  pattern,  and  in  such  a  way  that  at  one 
step  the  new  pattern  is  the  same  in  the  two  new  butter- 
flies and  differs  in  the  same  way  from  the  parent  pattern  ! 

Moreover,  the  possibility  of  the  same  large  variation 
suddenly  occurring  in  these  different  butterflies  is  rendered 
still  more  remote  by  the  fact  that  while  mima  and  wahlbergi 
are  forms  of  one  species,  echeria  and  dominicanus  are 
different  species  of  one  genus  and  by  no  means  closely 
related  within  that  genus.  The  two  examples  given  are 
therefore  not  analogous. 

Again,  in  Bedrock,  vol.  ii.  Professor  Punnett  discusses 
the  polymorphic  forms  of  the  mimetic  oriental  "  swallow- 
tail "  butterfly  Papilio  polytes.  He  says  :  "  Mr.  J.  C.  F. 
Fryer  has  recently  succeeded  in  carrying  out  an  elaborate 
series  of  breeding  experiments  with  this  species  and  has 
shown  that  any  form  of  female  can  produce  any  other 
form  provided  that  she  mates  with  an  appropriate  male, 
while  in  certain  cases  all  three  forms  may  appear  in  the 
same  brood.  Even  in  such  a  case  all  the  three  forms 
are  sharply  cut  and  clear,  there  being  a  complete  absence 
of  intermediates  or  transitional  forms." 

Incidentally  it  may  be  remarked  in  passing  that  had 
Mr.  Fryer  worked  with  the  African  Papilio  dardanus 
there  would  not  have  been  a  complete  absence  of  tran- 
sitional forms. 

At  first  sight  the  Mendelian  argument  seems  to  be  that 
absence  of  intermediates  is  proof  of  origin  by  mutation. 


270  PSEUDACRAEA   EURYTUS 

It  would  seem  therefore  that  abundance  of  intermediates 
as  in  the  case  of  the  Pseudacraeas  is  in  favour  of  the 
Darwinian  explanation.  But  the  Mendelian  claims  their 
presence  also  to  be  explicable  by  the  theory  of  mutations. 
Thus  in  the  same  article  in  Bedrock  Professor  Punnett 
discusses  the  various  offspring  of  a  cross  between  a 
"  Silky  hen  "  and  a  "  Brown  Leghorn  "  cock  which 
show  grades  of  transition,  and  says  :  "  Even  if  a  completely 
grading  series  "  can  be  put  together,  it  does  not  follow 
"  that  the  various  forms  have  arisen  through  the  accumu- 
lation of  minute  variations."  The  series  intergrading 
between  the  two  extremes  of  the  cock  and  hen  "  can  be 
expressed  in  terms  of  two  Mendelian  factors.  .  .  .  Thus 
an  appearance  of  continuity  in  variation  may  be  brought 
about  by  the  interaction  of  a  small  number  of  definite 
factors  upon  one  another."  And  in  Mendelism,  p.  162, 
Professor  Punnett  says:  "Neither  the  existence  of  such 
a  continuous  series  of  intermediates,  nor  the  fact  that 
some  of  them  may  breed  true  to  the  intermediate  con- 
dition, is  incompatible  with  the  Mendelian  principle  of 
segregation." 

In  his  book  on  Mimicry  in  Butterflies,  he  also  says,  on 
p.  129  :  "As  the  result  of  modern  experimental  breeding 
work  it  is  recognized  that  an  intermediate  form  between 
two  definite  varieties  may  be  so  because  it  is  heterozygous 
for  a  factor  for  which  one  variety  is  homozygous  and 
which  is  lacking  in  the  other — because  it  has  received 
from  only  one  parent  what  the  two  typical  varieties 
receive  from  both  parents  or  from  neither.  Its  germ 
cells,  however,  are  such  as  are  produced  by  the  two 
typical  forms,  and  the  intermediate  cannot  be  regarded 
as  a  stage  in  the  evolution  of  one  variety  from  the 
other.  ...  It  is  quite  possible  that  the  new  mimetic 
pattern  appeared  suddenly  as  a  sport,  and  that  the  inter- 
mediates arose  when  the  new  form  bred  with  that  which 
was  already  in  existence." 


INTERMEDIATES   AND   MUTATION   THEORY    271 

The  extraordinarily  varied  forms  of  P.  dardanus,  sub- 
species polytropJms,  on  the  high  Kikuyu  escarpment 
(6,500-9,000  feet)  in  British  East  Africa  do  not  support 
the  view  that  the  mimetic  patterns  arose  suddenly  and 
the  intermediate  forms  from  them  by  interbreeding. 
Many  of  these  transitional  forms  are  abundant  on  the 
escarpment,  but  are  very  rarely  found  elsewhere  ;  that 
is,  they  have  a  certain  peculiar  geographical  distribution. 
"  The  Kikuyu  escarpment  is  the  only  locality  at  present 
known  where  these  transitional  forms  make  up  a  large 
proportion  of  the  females."  ^ 

Such  a  distribution  is  far  more  consistent  with  the 
interpretation  that  these  are  an  ancestral  set  of  forms, 
such  as  may  have  existed  before  the  different  named 
forms  became  as  distinct  as  they  are  to-day,  which  have 
been  left  isolated  on  a  mountain  ridge. 

One  of  the  most  varied  of  all  these  ancestral  forms  is 
trimeni,  which  is  not  considered  to  be  an  intermediate 
between  two  other  forms  of  m-imetic  females,  but  to  show 
how  the  female  first  began  to  depart  from  the  ancestral 
type  like  the  male.  That  is  to  say,  trimeni  is  at  one  end 
of  the  long  series  of  female  forms,  and  cannot  be  supposed 
to  be  a  stage  between  two  others. 

Thus  it  is  seen  that  these  intermediate  forms  are  held 
by  both  Darwinian  and  Mendelian  to  support  the  respec- 
tive hypotheses  of  evolution,  but  the  latter  has  perforce 
to  fine  down  his  "  large  "  variations  or  "  sports  "  to  such 
a  small  size  that  they  appear  to  be  of  the  kind  which 
the  Darwinian  recognizes  as  "  small  "  variations  upon 
which  Natural  Selection  can,  and  apparently  does,  work. 

The  Mutationist  claims  that  if  these  differences  are 
inherited  according  to  Mendelian  laws  they  must  be 
of  the  nature  of  *'  large  "  variations ;  the  Darwinian 
claims  that  they  are  the   "  small  "  variations  which  he 

*  Poulton,  "  Mimicry,  Mutation  and  Mendelism,"  Bedrock,  vol.  ii, 
p.  49.     A  plate  in  this  article  shows  some  of  these  Kikuyu  forms. 


272  PSEUDACRAEA  EURYTUS 

believes   to   be   acted     upon    by   Natural   Selection,    and 
adduces  proof  that  they  can  be  inherited  ! 

One  can  quite  appreciate  the  argument  that  the  theo- 
retical origin  of  Euralia  wahlbergi  from  a  form  of  such 
different  appearance  as  mima  would  be  an  example  of 
origin  by  "  Mutation  "  or  *'  Sport,"  but  when  it  is  neces- 
sary to  fine  down  the  "  largeness  "  as  in  the  intermediate 
fowls  it  becomes  an  apparent  absurdity  to  allude  to  these 
differences  as  "  large,"  that  is,  as  "  sports."  It  seems 
difficult  to  draw  distinctions  between  the  Mendelian's 
"  Mutation,"  which  is  inherited  by  segregation  of  some 
very  minutely  differentiating  "  factor,"  and  the  Darwinian 
"  small  "  variation,  which  can  be  inherited,  but  which 
the  Mutationist  calls  a  "  fluctuation  "  and  says  is  non- 
heritable,  but  if  proved  to  be  heritable  claims  as  a 
"mutation"  or  "large  variation." 

If  segregation  comes  down  to  produce  such  minute 
differences,  the  term  "  large  variation,  mutation  or 
sport  "  seems  to  be  worn  rather  thin  ! 

On  this  matter  the  work  done  by  T.  H.  Morgan  upon  the 
colour  of  the  eye  in  the  fruit  fly  Drosophila  has  a  bearing. 
The  eye  is  normally  red,  but  in  the  investigations  upon 
the  inheritance  of  the  eye  colour  it  was  found  that  there 
were  seven  gradations  between  white  and  red,  and  further, 
one  of  the  grades  has  seven  modifying  factors,  each  of 
which  altera  its  intensity  and  gives  rise  to  a  secondary 
grade.  Professor  Jennings  remarks  that  "  by  means 
of  these  graded  changes  one  could  obtain,  by  the 
mutationist 's  own  statement,  the  continuously  graded 
results  which  selection  actually  gives.  What  more  can 
the  selectionist  ask  ?  "  ^ 

A  case  strictly  analogous  to  the  case  of  Ps.  eurytus, 
with  its  abundance  of  insular  variations  in  the  absence 
of  the  models,  is  noted  by  Professor  Poulton  in  his  presi- 

^  See   a  summary  of  Jennings'   papers   by   Professor  Poulton  in   the 
Proceedings  oj  the  Entomological  Society  oj  London,  1917,  pp.  Ixxxv-lxxxix, 


INTERMEDIATES   IN  ABSENCE   OF  MODELS     273 

dential  address  to  the  Linnean  Society  in  1916.  Dr. 
Lamborn  bred  Papilio  dardanus  on  the  west  coast  of 
Africa  (South  Nigeria),  where  the  black  and  white  form 
hippocoon  is  almost  the  only  form  known.  This  mimics 
the  abundant  Amauris  niavius.  Another  form  of  dardanus 
female  has  been  caught  rarely  all  along  the  tropical  west 
coast  of  Africa.  This  has  a  fore  wing  pattern  approaching 
that  of  hippocoon,  but  with  the  bar  between  the  subapical 
and  inner  marginal  white  areas  very  ill  defined,  and  the 
hind  wings  are  yellow  instead  of  white.  This  rare  form 
is  known  as  dionysus,  and  there  is  no  model  for  it  in 
Nigeria. 

Lamborn  bred  from  a  hippocoon  parent  nine  female 
forms  like  it,  but  also  eight  dionysus  which  has  never 
been  bred  before.  Now  these  dionysus  are  in  a  position 
similar  to  the  Pseudacraeas  which,  in  the  absence  of  control 
by  the  models  on  the  islands,  are  producing  large  numbers 
of  transitional  varieties,  for  no  two  of  them  are  alike, 
and  they  present  a  beautifully  graded  series,  from  a  fore 
wing  pattern  approaching  that  of  hippocoon  to  a  pattern 
closely  approaching  that  of  the  male.  The  nine  hippocoon 
sisters,  however,  mimicking  the  abundant  Amauris,  present 
a  very  close  resemblance  to  each  other  and  to  the  hippocoon 
parent. 

It  is  noteworthy  that  in  the  case  of  both  Papilio  dardanus 
and  Pseudacraea  eurytus  the  variation  in  the  absence 
of  models  is  best  shown  in  the  shape,  size,  and  sharpness 
of  outline  of  a  dark  bar  separating  the  paler  portions 
of  the  fore  wing  into  two  main  areas. 

We  now  come  to  discuss  another  point  of  great  interest. 
If  the  collections  of  Pseudacraea  eurytus  from  different 
islands  in  the  lake,  sometimes  very  close  together,  be 
compared,  further  evidence  in  favour  of  the  maintenance 
of  mimetic  resemblance  by  Natural  Selection  is  obtained. 

Although  the  islets  of  Kimmi  and  Ngamba  are  so 
very   close  to  each  other   and  Kome   (see   map),  yet  the 

19 


274 


PSEUDACRAEA  EURYTUS 


predominant   form   of   Psevdacraea  is   not   the   same   on 
each  island. 

At  each  locality  the  predominant  Pseudacraea  is  that 
which  mimics  the  species  of  Planema  that  is  most 
numerous  in  that  locality,  and  this  is  further  borne  out 
by  the  collection  from  Kakindu  on  the  mainland  to  the 
west  of  the  lake. 


Combina- 
tion. 

Models  and  Mimics. 

Kome, 
1914. 

Ngamba, 
1914. 

Kimmi, 
1914. 

Eakindu, 
1915. 

I 

PI.  macarista  J  poggei  (J  ?  . . 
Pa.  eurytus  hobleyi  ^ 

56 

8 

23 
9 

15 
2 

10 

1 

II 

PI.  macarista  $ 

aganice  montana  $ 
alcinoe  camerunica  $ 

Ps.  eurytus  tirikensia  ? 

}" 

8 

23 

7 

9 

2 

6 

III 

PI.  epaea  paragea  (J  ? 
Ps.  eurytus  obscura  c?  ? 

2 

2 

— 

16 

IV 

PI.  tcllus  eumelis  c?  ? 
P^.  eurytus  terra  (J  ? 

235 
35 

— 

— 

71 
12 

From  the  above  table  it  is  seen  that  while  on  Kome 
the  model  of  type  of  colouring  IV  {Planema  tellus)  was 
most  abundant,  on  Ngamba  the  species  that  predom- 
inated were  of  types  I  and  II,  and  on  each  island  the 
proportions  of  the  forms  of  Pseudacraea  are  according 
to  the  prevailing  type  of  models.  At  Kakindu,  again, 
type  IV  predominated  in  the  models,  and  all  the  Pseud- 
acraeas  save  one  were  of  type  IV.  The  islands  mentioned 
are  so  close  together  that  it  would  be  absurd  to  attempt 
to  explain   the  differences  in  the  Pseudacraea  fauna   by 


VARIED   FORMS   ON  DIFFERENT  ISLES     275 

climatic  conditions  ;  the  factor  that  varies,  however,  is 
the  proportion  of  species  of  Planema.  The  supposition 
is  that  on  Ngamba  a  form  of  Pseudacraea  that  does  not 
resemble  male  or  female  of  Planema  macarista  has 
less  chance  of  surviving  birds'  attacks  than  a  form  which 
is  deceptively  like  macarista  ;  consequently  the  form  terra, 
which  is  so  common  on  Kome  Isle  only  a  few  hundred 
yards  away,  is  at  a  disadvantage  on  Ngamba. 

This  explanation,  of  course,  presupposes  that  the 
species  of  birds  which  are  presumed  to  exercise  selection 
do  not  fly  across  from  Ngamba  to  Kome  or  vice  versa 
(see  map).  Now,  although  Bee-eaters  may  constantly 
be  seen  crossing  open  water  in  flocks,  I  do  not 
think  that  I  have  ever  seen  such  birds  as  Flycatchers, 
which  abound  on  the  islands  and,  in  some  cases  at  least, 
only  in  the  forest  which  is  the  haunt  of  Pseudacraeas, 
crossing  from  one  island  to  another.  I  have  even  noticed 
that  the  very  characteristic  songs  and  call  notes  of  species 
such  as  the  "  Kunguvu  "  (Tchitrea  emini)  and  a  pretty 
little  black  and  white  Platysteira  (?  jacksoni)  varied  on 
different  islands. 

While  on  Bugalla  in  1912-13,  I  became  extremely 
familiar  with  the  call  of  these  abundant  birds,  and 
directly  I  visited  the  Kome  group  of  isles  in  1914  at 
once  noted  a  difference — yet  the  difference  was  slight 
enough  to  make  me  feel  certain  that  the  species  of 
bird  was  the  same.  This  seems  to  show  that  at  any 
rate  on  islands  at  this  distance  apart  there  is  a  tendency 
for  geographical  races  to  be  perpetuated,  but  I  have 
not  been  long  enough  among  the  islets  of  the  Kome  group 
to  know  if  the  song  of  the  flycatchers  of  Ngamba  differs 
from  that  of  the  same  species  on  Kome.  Yet,  as  has 
been  shown  in  Chapter  VI,  many  islands  quite  close 
together  show  distinct  differences  in  their  avian  fauna. 


CHAPTER   XII 

HYMENOPTERA 

Ants. 

The  ant  that  most  obtrusively  calls  for  notice  is  the 
well  known  Dorylus  or  "  Safari  ant,"  known  to  the 
Baganda  as  "  Ensanafu  "  and  in  Kiswahili  called 
"  Siafu."  1 

This  totally  blind  reddish  ant  varies  exceedingly  in 
size,  the  largest  individuals  being  half  an  inch  long  and 
several  times  larger  than  the  smallest,  but  it  is  diificult 
to   make  out  any  difference  in  their  functions. 

They   live   entirely   by   hunting   live   prey,    and   ov/ing 
to    their    incredible    numbers    must    destroy    very    many 
of  the  creatures  that  are  unable  to  escape  them.     They 
make    temporary    subterranean    nests,   which   are    easilyJ 
discovered  on  account  of  the  piles   of  loose   earth   that] 
has   been   brought  up    from    below  grain   by  grain,   and] 
the  numerous  large  irregular  holes  leading  down  to  the] 
burrows  and  chambers  in  which  the  queen  lives  and  the] 
young  are  reared.     The  queen  is  a  curious  looking  creature,! 
with  abdomen  much  enlarged,  as  is   the   case  with    thej 
well    known     queen     termite,     but    in    the     latter    the 
distension  is  very  much  greater. 

Queen  Dorylus  are  rare  in  museums,  probably  becausej 
of  the  courage  that  is  required  to  dig  one  out  of  the  nest 
among  the  hordes  of  ferociously  biting  workers  ;    a  native 
once  brought  me   two,   but  I  should  have  liked  to  see 

1  Dorylus   nigricans   and   glabratus. 
276 


ENSANAFU  ANTS  277 

him  getting  them,  from  a  safe  distance  !  The  adult 
male  has  been  elsewhere  alluded  to  in  connection  with 
signs  of  the  weather.  The  worker  Dorylus  are  often 
seen  travelling  swiftly  in  a  column  several  ants  wide, 
in  a  very  orderly  manner  :  hence  the  name  Safari  ant. 
They  prefer  a  sheltered  route  among  and  under  leaves 
or  dense  grass,  but  where  they  must  cross  an  open  smooth 
area  such  as  a  well  trodden  path,  they  sometimes  make 
a  tunnel  for  at  least  part  of  the  way  beneath  the  surface, 
or  a  deep  furrow.  At  other  times,  however,  they  protect 
the  travellers  by  forming  a  line  on  each  side  of  the  track, 
the  ants  standing  high  on  their  legs  with  mandibles 
wide  agape  as  if  seeking  for  something  to  bite.  These 
guardians  are  so  intertwined  that  they  make  a  living 
wall  which  often  bridges  right  across  the  ceaseless  stream 
hurrying  below.  If  interfered  with,  or  disturbed  by 
the  tramp  of  a  foot  shaking  the  ground,  they  break  loose 
and  run  about  with  menacing  jaws,  but  do  not  go  far, 
and  if  nothing  is  met  within  a  yard  of  the  column 
the  guardians  return  and  re-form  the  protective  wall. 
These  columns  of  hurrying  ants  fill  one  with  amazement 
on  account  of  the  immense  numbers  of  individuals. 

The  first  one  I  saw  was  crossing  a  road  close  to  my 
hut  on  the  evening  of  July  18,  1910,  and  next  morning 
the  stream  was  still  showing  no  signs  of  abating.  It 
was  about  an  inch  wide,  and  4-6  ants  across.  At  noon 
the  ants  were  still  pouring  across  the  road  in  the  same 
direction,  but  by  5  p.m.  those  forming  the  protecting 
walls  had  moved,  and  by  sunset  they  had  all  gone  across  : 
that  is,  for  about  twenty-four  hours  there  had  been  a 
continual  stream,  for  there  is  no  reason  to  suppose  that 
this  column  was  exceptional,  and  had  ceased  to  move 
when  night  fell. 

This  column  was  apparently  changing  camp,  for  nearly 
every  ant  carried  a  naked  white  pupa,  although  it  is  a 
curious  fact  that  not  a  single  larva  was  seen  in  the  pro- 


278  HYMENOPTERA 

cession.  Indeed,  it  may  here  be  said  that  I  have  never 
seen  Dorylus  carrying  its  larvae  on  safari,  only  the  pupae  ; 
nor  does  one  ever  see  a  queen  travelling.  Is  it  possible 
that  a  column  such  as  is  above  described  is  analogous 
to  a  swarm  of  bees,  but  that  instead  of  taking  a  queen 
with  them  the  members  of  the  swarm  carry  pupae,  from 
one  of  which  a  queen  will  emerge  when  they  have  ex- 
cavated a  new  nest  ?  It  is  curious  that  where  there  are 
large  and  small  ants  there  should  not  be  some  differen- 
tiation of  function.  Quite  small  individuals  are  seen 
struggling  along  carrying  enormous  pupae,  while  lusty 
fellows  of  the  biggest  size  appear  quite  content  whether 
they  are  carrying  a  small  individual  or  one  of  their  own  bulk. 

Although,  on  the  whole,  the  column  is  an  orderly  one, 
occasionally  considerable  confusion  is  caused  by  indi- 
viduals running  back  against  the  stream  ;  possibly  they 
are  "returning  empty"  !  If  they  are  of  very  small  size, 
they  are  often  seen  to  be  unable  to  make  headway  against 
the  hurrying  multitude,  and  unless  they  run  quite  at 
the  edge  are  at  length  compelled  to  turn  round  and  run 
with  the  rest.  A  very  large  individual,  however,  since 
it  stands  well  above  the  small  ones,  can  often  run  against 
the  tide,  for  the  small  ones  can  run  under  it,  between 
its  legs. 

But  every  column  of  Ensanafu  that  one  sees  is  not 
engaged  in  changing  camp  ;  most  often  they  are  either 
going  out  to  hunt,  or  returning  laden  with  spoils. 

When  they  have  reached  the  hunting  ground  the  main 
column  breaks  up  into  minor  streams,  and  the  ants  swarm 
over  the  ground,  investigating  every  nook  and  cranny 
and  climbing  up  bushes. 

If  one  is  in  the  forest  when  they  are  hunting,  one  often 
first  becomes  aware  of  it  by  hearing  a  peculiar  pattering 
noise,  caused  by  the  countless  ants  which  have  run  up 
branches  to  the  extreme  tip,  and  finding  no  prey  there 
drop  off  and  fall  on  to  the  leaves  below. 


ENSANAFU  ANTS  279 

Their  activities  are  also  revealed  by  the  great  dis- 
turbance they  cause  among  the  countless  spiders  and 
insects  of  all  kinds  that  have  previously  been  concealed 
among  the  dead  leaves  and  ground  cover.  Before  one 
sees  the  hunters  themselves  one  meets  spiders,  harvest- 
spiders  (Phalangeridae),  caterpillars  and  especially  cock- 
roaches scurrying  away  in  great  excitement.  As  one 
draws  nearer  to  the  area  being  hunted  over,  one  sees 
little  masses  of  Dorylus  ants  busily  engaged  in  cutting 
up  some  unfortunate  insect  that  has  failed  to  escape, 
and  then,  standing  just  outside  the  area  and  keeping 
careful  watch  around  one's  feet,  one  can  see  the  hunters 
running  about  and  going  into  every  nook  and 
cranny. 

A  cockroach  takes  fright  and  rushes  out  from  under 
some  dead  leaves,  only  to  be  seized  by  one  or  more  ants 
and  overpowered  by  superior  numbers.  Sometimes,  on 
a  sandy  shore,  where  they  have  a  chance  of  running  away, 
the  cockroaches  forfeit  their  lives  by  losing  all  presence 
of  mind  and  running  wildly  hither  and  thither,  often 
tumbling  head  over  heels  in  their  frantic  endeavours  to 
escape,  and  so  falling  all  the  easier  prey. 

Sometimes,  however,  certain  spiders  by  moving 
cautiously  first  in  one  direction  and  then  in  another, 
and,  as  it  were,  feeling  their  way,  manage  to  evade  the 
awful  fate  of  being  eaten  alive. 

It  is  an  unpleasant  sight  when  a  huge  caterpillar  is 
seen  writhing  and  twisting  in  the  endeavour  to  free  itself 
from  the  numerous  ants  which  have  firmly  fixed  their 
sharp  jaws  in  its  skin  and  will  not  leave  go. 

Slugs  of  large  size  are  cut  up  piecemeal,  although  some 
of  the  ants  at  least  are  overwhelmed  and  suffocated  in 
the  slime  that  is  secreted  more  abundantly  when  the 
slug  is  attacked. 

A  certain  snail  that  was  common  on  Damba  Isle 
was  able,  as  related  in  another  chapter,  to  keep  the  ants 


280  HYMENOPTEUA 

at  a  distance  by  surrounding  itself  with  bubbles  of  foam 
into  which  the  ants  could  not  penetrate. 

A  medium  sized  Plant  bug  (Hemiptera)  was  once  seen 
on  a  leaf  of  a  bush  over  which  Dorylus  was  swarming, 
and  I  was  much  interested  to  note  that  although  ants 
would  frequently  seize  hold  of  a  limb  or  antenna  of  the 
bug  they  always  let  go  again,  and  no  harm  was  done  to 
the  bug.  It  is  possible  that  its  powerful  odour  may 
have  been  disagreeable  to  the  ants. 

One  night  a  large  army  of  Ensanafu  raided  my  grass 
hut  on  Bugalla  Isle  ;  fortunately  I  was  sleeping  in  a 
tent  close  by,  and  though  a  column  ran  through  the 
tent  they  were  only  on  the  way  to  the  hut,  and  I  was 
not  turned  out.  But  a  nestful  of  fledgling  swallows  in 
one  corner  of  the  hut  was  cut  up  and  carried  away  piece- 
meal. 

One  day  at  Jinja  I  heard  pitiful  squeakings  coming 
from  some  long  grass,  and  found  a  baby  striped  rat  being 
attacked  and  in  danger  of  a  horrible  fate  ;  needless  to 
say  he  was  freed,  but  very  likely  fell  a  victim  subsequently. 

During  the  campaign  in  German  East  Africa  I  was 
twice  turned  out  of  the  little  tent  in  which  I  was  sleeping 
on  the  ground  by  an  invasion  of  Ensanafu,  and  had  to 
bolt,  and  then,  after  picking  off  those  ants  which  had 
already  attached  themselves  to  various  parts  of  my 
person,  make  a  dash  for  boots,  and  by  frequent  painful 
visits  gradually  withdraw  the  bedding  and  shake  down 
elsewhere  outside,  while  the  ants  proceeded  along  the 
line  to  some  one  else's  tent,  to  my  secret  gratification, 
for  no  one  likes  to  be  the  only  one  who  is  turned  out  in 
the  night  ! 

On  Damba  Isle  in  July  1911,  I  saw  a  very  interesting 
thing  while  watching  the  unfortunate  denizens  of  the 
shady  forest  being  turned  out  by  Dorylus.  Cockroaches 
were  scurrying  about  in  all  directions,  and  hovering 
over  them,   and  occasionally  darting  down  upon  them, 


ENSANAFU  AND  STINK  ANTS  281 

was  a  small,  thin  bodied,  long  legged  insect  whose  appear- 
ance suggested  a  Syrphid  fly,  though  one  seemed  to  have 
a  short  ovipositor,  which  would  imply  that  it  was  an 
"  Ichneumon  "   fly. 

After  watching  for  some  time  I  suspected  that  the 
fly's  object  was  to  dart  down  and  lay  an  egg  upon  a 
cockroach  before  it  was  cut  up  by  the  ants.  Presumably 
the  egg  would  thus  be  carried  into  the  nest,  where  the 
larva  would  find  food  that  it  required,  and  possibly  frag- 
ments of  insects  that  had  been  brought  in  by  the  ants. 

Bates,  in  his  Naturalist  on  the  Amazons,  describes 
something  similar  in  the  case  of  Stylogaster  and  the  Eciton 
ant,  which  has  habits  analogous  to  those  of  Dorylus. 

In  July  1914,  I  saw  an  interesting  affair  on  Bulago 
Island.  A  small  column  of  Ensanafu  was  hunting,  and 
had  discovered  in  a  hollow,  broken  cane  stem  the  nest  of 
another  ant,  a  large  black  species  whose  rotund  abdomen 
is  covered  with  golden  pubescence.  The  rightful  owners 
of  the  nest  had  found  discretion  the  better  part  of  valour, 
and  were  no  longer  attempting  to  resist  the  raiders,  who 
had  bitten  through  the  stopper  closing  one  end  of  the 
stem.  Some,  inside,  brought  up  the  grubs  in  the  nest, 
which  were  at  once  seized  by  eager  helpers  outside,  who 
usually  fell  to  the  ground  with  their  burden  in  their 
excitement.  It  was  a  busy  scene,  and  curiously  reminded 
one  of  the  unloading  of  a  ship. 

Another  abundant  ant  is  the  giant  Paltothyreus  tarsatus, 
known  to  natives  as  "  Waka,"  and  to  Europeans  as 
"  Stink  ant,"  owing  to  the  appalling  smell  of  bad  eggs 
emitted  by  it  when  roughly  handled.  About  an  inch 
long,  coal  black  in  colour,  this  species  is  often  seen  singly 
slowly  wandering  about  searching  for  food.  It  seems  to 
live  on  animal  food — small  insects  or  bits  of  dead  ones 
which  it  meets  with  on  its  wanderings — but  is  not  active 
in  its  movements.     If  handled  it  can  inflict  a  severe  sting. 

The  Waka  nests  underground,  and  in  disused  chambers 


282  HYMENOPTERA 

in  the  base  of  old  termite  hills  :  one  such  nest  that  I  dug 
out  was  perceptible  to  the  nose  from  some  yards  away. 
When  the  nest  was  broken  open  the  ants  and  termites 
running  about  of  course  met,  and  the  termite  invariably 
seized  hold  of  the  ant.  But  the  ant  seemed  to  be  too 
hard  for  the  termite  to  make  any  impression  on  it,  and 
if  unable  to  free  itself  by  struggling  turned  its  abdomen 
forwards  and  deliberately  stung  the  termite,  which  at 
once  let  go  and  seemed  more  or  less  paralysed.  One  ant 
was  tackled  successively  by  two  termites,  and  accounted 
for  each  in  turn,  but  it  was  never  the  aggressor,  and 
seemed  reluctant  to  sting  until  other  methods  failed  to 
release  it  from  the  termite's  grip.  I  have  found  a  winged 
male  of  this  ant  in  the  stomach  of  a  Bee-eater. 

Another  large  black  ant  that  is  often  confused  with 
Paltothyreus  is  Megaponera  fmtens,  though  it  is  con- 
siderably smaller,  has  no  odour,  and  is  of  very  different 
habits.  The  name  foetens  should  apply  to  Paltothyreus, 
with  which  this  ant,  called  "  Enkolokoto  "  by  the  natives, 
must  have  been  confused  when  the  name  was  given 
to  it. 

I  mention  this  ant  because  it  is  absent  from  the  islands, 
nor  have  I  met  with  it  on  the  Uganda  shores  of  the 
lake. 

I  first  saw  it  when  on  active  service  on  the  southern 
frontier  of  Uganda  in  1914  (Kagera  river),  and  subse- 
quently became  very  familiar  with  it  in  German  East 
Africa.  But  the  Kagera  river,  which  forms  the  natural 
boundary  to  Uganda,  also  seems  to  act  as  a  barrier 
to  Megapo7iera  in  that  part  of  the  world,  for  though  the 
ant  is  often  seen  on  the  south  side  of  the  river,  it  was 
apparently  absent  from  the  north  side.  I  was  informed 
by  a  missionary,  however,  that  he  knew  it  well  further 
north  in  Uganda. 

Megaponera  feeds  on  termites,  and  marches  out  in 
orderly  bands  of   a   hundred   or   more,   and  when  inter- 


HOUSE    ON    BUGALLA,    I912-I3. 
Barbed  wire  lightning  conductor  over  supports  on  roof. 


INTERIOR    OF    BUGALLA    HOUSE. 


To  face  p.  282. 


SUNDRY   ANTS  288 

fered  with  produces  a  distinct  stridulating  or  squeaking 
noise.  These  characteristics  make  it  easy  to  recognize. 
Probably  it  is  absent  from  the  lake  area  because  its 
favourite  prey  is  not  found  there.  This  is  a  species  of 
dark  coloured  termite  which  does  not  build  hills,  but 
lives  in  burrows  underground,  from  the  open  mouths 
of  which  they  come  out  in  daylight  to  cut  the  segments 
of  grass  blades,  which  they  then  drag  down  and  pre- 
sumably eat. 

The  remarkable  ant  (Ecophylla  smaragdina  has  already 
been  alluded  to  on  account  of  its  being  mimicked  by  a 
spider  and  a  bug.  It  is  not  found  by  any  means  on  all 
islands,  but  was  common  on  the  trees  overhanging  the 
"  fly  beach  "  on  Damba.  The  nest  is  a  globular  shell 
formed  by  leaves  attached  together  along  their  edges 
with  silk  spun,  as  H.  N.  Ridley  first  pointed  out,  by  a 
larva  held  between  the  jaws  of  an  ant  for  that  especial 
purpose,  and  applied  first  to  the  edge  of  one  leaf  and 
then  to  another.  It  is  an  inoffensive  species,  its  feeble 
mandibles  being  barely  able  to  pierce  one's  skin,  and 
being  without  a  sting. 

On  Damba  they  fed  largely  on  the  thousands  of  small 
"  E'sami  "  lake  flies  (Chironomidae)  which  settle  on  the 
leaves,  but  also  from  secretions  of  Aphidae  on  the  stems 
of  the  leaves.  The  island  specimens  were  of  a  shining 
light  brown  colour  and  form  a  distinct  race,  known  as 
longinoda.  Some  that  I  saw  in  Portuguese  East  Africa 
in  1918  were  more  of  a  greyish  brown  tint. 

Another  ant  that  lives  on  leaves  of  trees  is  known 
to  the  Baganda  as  "  Obusaji-saji,"  but  unfortunately  no 
specimens  were  obtained  for  identification. 

It  was  very  abundant  on  Bugalla  and  Damba,  but  does 
not  occur  on  many  islands.  It  is  a  small,  very  active 
long  legged  black  species,  which  makes  a  frail  nest  of 
some  friable  brown  material  on  the  backs  of  leaves  or 
between  two  leaves,   which  thus  adhere  together. 


284  HYMENOPTERA 

If  one  is  so  unfortunate  as  to  disturb  these  when  pushing 
between  leafy  branches,  great  numbers  of  the  little  ants 
rush  out,  and,  getting  a  firm  grip  with  their  man- 
dibles, inflict  a  sting  which  leaves  a  burning  irritation 
for  several  hours.  It  is  particularly  unpleasant  when 
they  find  their  way  down  one's  back  or  into  one's  hair  ! 

The  most  noticeable  wasps  are  species  of  the  genus 
Belonogaster  :  large,  dark,  grey-brown  insects  with  long 
pedicle  to  the  abdomen,  known  as  "  E'numba  "  by  the 
natives.  Their  nest  is  of  papery  substance,  and  formed 
of  a  single  tier  of  cells  supported  from  a  slender  stalk, 
with  the  open  mouths  downwards.  It  is  attached  to 
the  under  side  of  an  overhanging  rock,  or  to  the  eaves 
of  a  house,  and  in  a  favourite  site  numbers  of  nests  are 
seen  close  together. 

Natives  are  very  much  afraid  of  the  sting  of  these 
wasps,  which  is  certainly  extremely  painful,  and  do  not 
like  going  near  their  nesting  places.  It  must  be  acknow- 
ledged that  there  is  reason  for  this,  for  sometimes  a 
wasp  will  fly  ofE  the  nest  and  viciously  sting  any  one 
who  it  thinks  has  come  too  close,  returning  immedi- 
ately to  the  nest.  I  noticed,  however,  that  if  one  allows 
a  nest  to  grow  up  in  a  position  constantly  approached 
or  passed  by,  the  wasps  become  accustomed  to  people, 
and  are  inofifensive  as  a  general  rule. 

I  allowed  several  nests  to  be  built  from  the  underside 
of  the  ridge  of  my  tent,  and  the  colonies  grew  to  a  large 
size  without  any  sign  of  aggressiveness  on  the  part  of 
the  wasps.  But  one  day  an  officious  individual,  perhaps 
a  freshly  hatched  and  inexperienced  one  who  had  not 
been  taught  properly,  flew  off  at  me  when  I  came  into 
the  tent  and  inflicted  a  vicious  sting.  This  sealed  the 
death-warrant,  and  all  the  nests  were  destroyed. 

The  grubs  in  their  cells  hang  mouth  downwards,  the 
anterior  end  of  the  body  protruding  slightly.  They  are 
watched  over  by  certain  individuals  who  act  as  nurses, 


BELONOGASTER  WASPS  285 

while  others  go  out  hunting  for  the  smooth  caterpillars 
wherewith  to  feed  them. 

A  wasp  having  found  a  caterpillar  pounces  on  it  and 
stings  it,  and  at  once  begins  to  pulp  it  with  its  large 
mandibles,  beginning  at  one  end  and  passing  systemati- 
cally along  the  whole  body.  Finally,  the  mangled  remains 
are  rolled  up  into  a  pellet  about  the  size  of  a  pea,  with 
which  the  successful  hunter  flies  back  to  the  nest.  In 
one  case  that  was  observed  two  wasps  were  on  the  nest 
when  the  hunter  (A)  returned  with  a  mashed-up  insect 
in  her  mandibles.  This  she  gave  to  B,  who  appeared  to 
mince  it  up  further  and  then  shared  it  with  C,  each 
going  to  one  of  the  larger  larvae  in  the  cells  and  holding 
the  mass  to  its  mouth.  The  larvae  could  be  seen  eating 
it.  A  afterwards  went  round  and  fed  the  larvae  with 
fluid  regurgitated  :  this  process  was  accompanied  by  a 
kind  of  violent  shuddering  motion.  I  could  see  the 
drop  of  fluid  appearing  between  the  wasp's  mandibles, 
to  be  slowly  sucked  up  by  the  larva. 

Caterpillars  are  not  the  only  prey  of  Belonogaster, 
for  one  frequently  sees  them  capturing  and  pulping 
small  brown  Acraea  butterflies,  which  is  of  interest 
when  considering  the  enemies  of  protected  insects.  The 
Belonogaster  itself  may  be  considered  a  typical  pro- 
tected insect,  but  I  have  found  it  in  the  stomach  of  a 
Bee-eater  {Merops  superciliosus).  This  subject  is  discussed 
elsewhere. 

Belonogaster  has  all  the  characteristics  of  a  protected 
species,  and  serves  as  a  model  for  a  most  interesting 
Neuropterous  insect,  Mantispa,  which  has  been  elsewhere 
described. 

Although  it  is  not  considered  too  formidable  by  the 
Bee-eater,  which  seems  to  be  specially  adapted  to  feed 
on  stinging  insects,  there  are  probably  few  other  birds, 
and  certainly  no  mammals,  that  would  dare  to  catch 
it,   so   that   its   enemies   must   be   mainly   other   insects. 


286  HYMENOPTERA 

There  are  often  to  be  seen  in  empty  cells  of  the  nest  the  . 
pupa  cases  of  flies,  one  to  a  cell,  probably  Tachinidae, 
but  I  have  not  actually  seen  a  fly  depositing  its  egg  on 
the  wasp  larva.  These  wasps  belong  to  the  Diploptera, 
or  true  wasps,  whose  wings  are  doubled  up  longi- 
tudinally when  not  in  use,  giving  them  a  very  narrow 
appearance. 

In  the  group  of  wasp-like  insects  now  to  be  discussed, 
known  as  the  Fossores,  the  wings  are  not  folded.  While 
some  of  them,  such  as  Bembex,  have  a  certain  resemblance 
to  a  true  wasp,  most  of  them  are  readily  distinguished. 

The  group  is  remarkable  from  the  habits  whence  the 
name  Fossores,  which  means  "  diggers,"  is  derived  ; 
they  are  also  called  "  Sand  wasps."  The  wasp  Belonogaster 
has  been  described  above  as  feeding  its  young  on  insects 
which  it  has  first  killed  and  pulped.  It  is  obvious  that 
meat  of  such  kind  must  be  troublesome  to  prepare,  and 
must  be  supplied  fresh  at  frequent  intervals. 

Some  other  wasps,  which  are  of  solitary  habits  (Odynerus, 
etc.),  do  not  pulp  the  prey,  but  store  them  up  whole  in 
their  burrow.  But  if  one  examines  the  store  that  has 
been  laid  up  for  the  larva  to  feed  upon,  one  finds  that 
in  the  case  of  small  geometrid  caterpillars,  some  of  them 
shrivel  and  dry  up,  and  are  not  in  very  good  condition  to 
form  food. 

One  family  of  fossors,  the  Bembecidae,  has  slightly 
improved  upon  this  method.  They  feed  their  larvae 
almost  entirely  upon  whole  flies,  which  they  do  not 
kill,  but  sting  so  that  they  remain  alive  and  juicy  but 
cannot  move,  since  the  central  nervous  system  has  been 
paralysed  ;  probably,  therefore,  they  are  insensitive  as 
well.  Regular  supplies  of  these  paralysed  flies  are  taken 
down  into  the  burrow  by  the  mother  Bembex. 

A  further  step  in  the  saving  of  trouble  is  exemplified 
by  other  fossors  of  the  families  Sphegidae  and  Pompilidae. 
These  lay  up  in  a  burrow  a   store    of  paralysed  insects 


FOSSORS  287 

sufficient  to  feed  one  grub  for  the  whole  period  of  its 
growth.  Having  stocked  the  burrow,  the  mother  lays 
an  egg,  affixing  it  to  one  of  the  living  but  helpless  prey, 
and  having  sealed  up  the  burrow  for  good  and  all,  she 
goes  off  to  make  another.  Sometimes  this  process  in- 
volves very  heavy  labour,  for  the  inert  grasshopper, 
caterpillar  or  spider  has  to  be  taken  to  the  burrow. 
Usually  it  is  too  heavy  to  be  carried  in  flight  ;  some- 
times it  can  be  carried  walking,  but  often  it  has  to  be 
dragged  along  the  ground.  In  the  latter  case  the  fossor 
first  finds  and  stings  the  prey,  and  then  excavates  the 
burrow  in  a  suitable  spot  in  the  neighbourhood  ;  but  if 
she  can  carry  her  prey  the  burrow  is  excavated  first  and 
the  prey  carried  back  to  it,  gripped  by  the  mandibles 
and  carried  between  the  legs.  It  is  wonderful  with  what 
accuracy  the  mother  will  find  her  way  over  sticks,  stones, 
bare  patches  of  sand,  or  through  thick  grass,  until  the 
burrow  is  reached ;  sometimes  she  travels  backwards 
with  her  load  ! 

It  is  an  obvious  saving  of  this  labour  to  find  the  prey 
first,  and  then  excavate  the  burrow  where  it  lies. 

Another  family,  however,  the  Scoliidae,  has  economized 
labour  even  further.  The  larvae  of  these  fossors  feed 
upon  the  subterranean  larvae  of  large  Lamellicorn  beetles. 
The  mother  burrows  down  to  them  and  merely  lays  her 
egg  upon  them  in  situ,  presumably  stinging  them  first 
to  render  them  inert,  as  is  the  custom  in  the  Fossores. 

Lastly,  there  are  the  peculiar  Mutillidae,  whose  wingless 
females,  as  they  run  swiftly  over  the  ground,  look  like 
brightly  coloured  ants.  These  are  mainly  parasitic  upon 
other  Hymenoptera,  and  do  not  burrow,  but  pierce  through 
the  walls  of  the  nest  and  lay  their  egg  upon  the  larva 
inside,  just  as  the  typically  parasitic  "  Ichneumon  "  fly 
lays  its  egg  upon  a  caterpillar.  Thus  one  can  trace  all 
stages  between  the  somewhat  crude  method  of  the 
Belonogaster  wasp  down  to  the  labour  saving  parasitism 


288  HYMENOPTERA 

of  the  Mutilla  and  the  well  known  "  Ichneumon  "  fly, 
parasites  of  caterpillars. 

It  may  be  remarked  here  that  "  parasite "  hardly 
seems  the  correct  term  for  an  Ichneumon  larva,  whose 
activities  necessarily  result  in  the  death  of  its  host,  which 
is  devoured  as  completely  as  an  antelope  is  by  a  lion. 

The  only  difference  is  that  at  first  the  young  Ichneumon 
larva  feeds  only  upon  the  juices  of  its  prey,  and  the 
essential  tissues  are  not  devoured  until  the  larva  is  full 
grown,  when  it  has  nothing  to  fear  in  the  death  of  its 
unwilling  host. 

It  does  occasionally  happen,  however,  if  the  dispro- 
portion in  size  is  great  between  the  host  and  the  parasite, 
or  if  the  number  of  parasites  is  very  small,  that  the  host 
is  not  killed.  I  once  reared  an  Arctiid  moth  and  a  single 
parasitic  Tachinid  fly  from  the  same  caterpillar  ! 

The  habits  of  Bembecidae  are,  like  those  of  other  fossors, 
of  absorbing  interest.  As  has  been  pointed  out,  these 
feed  their  larvae  on  flies, ^  but  they  do  not  lay  up  one  store 
for  good  and  all  as  do  the  Sphegidae  and  Pompilidae. 
Perhaps  the  reason  is  that  the  flies,  not  being  large-bodied, 
fleshy  insects,  might  dry  up  before  the  Bembex  larva 
had  eaten  them  all.  So  the  mother  attends  to  her  larva, 
bringing  to  it  freshly  stung  flies  at  frequent  intervals. 

Since  this  necessitates  constant  work  opening  and 
closing  the  burrow,  it  is  dug  in  localities  where  the 
soil  is  very  loose  and  light,  such  as  a  sandy  shore  on  the 
lake,  and  I  have  found  thriving  colonies  of  Bembex  in 
such  situations. 

The  first  that  I  met  with  was  on  a  dazzlingly  white 
beach  of  fine  sand  on  the  south  coast  of  Nsadzi  Island, 
in  March  1911,  when  I  found  numbers  of  B.  forcipata 
flying  about  over  the  hot  sand,  and  busily  excavating 
their  burrows,   and  spent    many  hours   watching    them, 

^  Occasionally  on  other  insects.  I  have  watched  one  catch  a  "  Skipper" 
butterfly.     See  Proc.  Ent.  Soc,  1917,  p.  xli. 


BEMBEX  289 

for  I  soon  saw  that  they  were  catching  Tse-tse  fly. 
A  Bembex  would  alight  on  the  sand  at  a  spot  which 
she  evidently  knew,  although  it  was  indistinguishable 
from  the  surrounding  bare  area,  and  commence  to  dig 
away  the  loose  sand  with  her  powerful  toothed  fore  limbs, 
specially  adapted  for  this  work  by  a  fringe  of  stiff  hairs. 
So  rapidly  does  she  work  that  the  sand  is  thrown  behind 
her  in  a  continuous  stream,  passing  underneath  her  body 
and  falling  a  couple  of  inches  behind. 

Without  a  pause  she  persists,  and  soon  lays  bare  the 
mouth  of  a  pre-existing  tunnel,  at  the  bottom  of  which 
lies  her  grub,  hungrily  devouring  flies.  As  she  works 
in  the  loose  sand  it  constantly  trickles  down  from  above, 
but  she  removes  it  at  such  speed  that  it  is  thrown  out 
faster  than  it  falls,  and  presently  the  burrow  is  clear  and 
she  disappears  from  sight  into  it. 

Sometimes  she  throws  up  behind  her  enough  sand  to 
block  the  entrance  ;  if  she  does  this  she  usually  remains 
below  for  some  time,  but  what  she  does  down  there  I 
know  not. 

Presently  up  she  comes,  and,  if  she  is  careful,  turns 
away  from  the  mouth  of  the  burrow  and  throws  enough 
sand  back  into  it  to  block  the  entrance.  The  reason  for 
this  will  be  given  later. 

But  quite  often  the  careless  worker  flies  away  without 
closing  the  burrow,  leaving  the  helpless  grub  at  the  mercy 
of  any   marauder  that  discovers   the  opening. 

Now  the  busy  mother  has  to  seek  food  for  her  young, 
and  she  flies  round  and  round  me  as  I  sit  on  the  sand, 
apparently  looking  for  a  nice  fat  Tse-tse  fly  full  of  blood  ! 
Naturally  she  finds  none,  and  has  to  take  the  next  best, 
but  searches  very  carefully,  coming  within  an  inch  of 
my  face  and  under  the  brim  of  my  hat.  Sometimes  a 
Tse-tse  that  has  been  sitting  on  my  clothes  takes  alarm 
and  darts  away,  but  not  quickly  enough  to  escape  its 
enemy,  who  pounces  on  it  in  a  flash, 

20 


290  HYMENOPTERA 

There  is  a  shrill  buzz,  like  a  scream,  from  the  fly  as 
it  is  caught  and  stung,  and  then  the  Bembex  is  seen  to 
be  holding  the  fly  closely  to  her  abdomen  between  the 
thighs  of  her  hind  legs,  and  darts  away  to  her  burrow. 

Sometimes  the  Bembex  pounces  on  a  fly  as  it  sits  on 
my  clothes,  and  I  am  able  actually  to  see  her  sting  it. 

Arriving  at  her  burrow,  Bembex  alights  at  the  exact 
spot,  and  without  a  moment's  hesitation,  still  holding 
her  prey  between  her  legs,  opens  up  the  burrow  and 
passes  in. 

Almost  immediately  she  emerges  again  and  repeats 
the  chase.  On  March  13th  I  thus  watched  one  worker 
for  three  and  a  quarter  hours,  during  which  she  caught 
twenty-nine  Tse-tse  and  two  other  flies.  The  last  four 
Tse-tse  had  been  caught  and  carried  into  the  burrow  in 
five  minutes.  After  this  she  finally  closed  the  burrow 
and  flew  away,  and  I,  with  great  difficulty  in  the  loose 
sand,  found  the  chamber  at  the  end  of  the  burrow  and 
took  out  all  the  flies  that  had  been  collected,  and  the 
legless  white  grub,    full   grown. 

There  were  thirty-one  Tse-tse  flies  and  one  other  fly. 
About  half  a  dozen  of  them  were  dried  and  some  partially 
eaten.  Twenty-one  were  males  and  ten  females,  eight 
of  which  were  fat  ones  containing  a  larva  ;  this  is  a  very 
high  percentage  of  pregnant  flies,  for  out  of  ninety-six 
female  flies  that  had  been  caught  by  my  boys  that 
morning  only  22  per  cent,  contained  large  larvae. 
So  that  the  Bembex  had  definitely  selected  the  fattest 
flies  she  could  find  in  default  of  full  fed  individuals,  which 
are  heavier  on  the  wing  and  easier  to  catch. 

Another  specimen  was  seen  to  catch  six  Tse-tse  and 
several  other  flies  in  an  hour  ;  if,  after  close  examination, 
8he  found  no  suitable  Tse-tse  on  me,  she  would  fly  away 
and  return  with  other  flies,  though  once  she  came  with 
a  Tse-tse  caught  elsewhere. 

The  burrow  of  another  that  was  dug  up,  about  eight 


BEMBEX  291 

inches  deep,  contained  a  nearly  full  grown  larva  and 
twenty  freshly  caught  flies,  one  of  which  was  as  large 
as  a  "  blue-bottle,"  but  the  rest  were  all  about  the  size 
of  the  common  house  fly,  and  appeared  to  be  of  several 
species — three  of  one  species,  nine  of  another,  one  of 
another,  two  of  another,  one  of  another,  and  three  of 
another. 

It  is  a  curious  fact  that  the  mother  does  not  know 
when  to  cease  provisioning  the  burrow,  and  gives  her- 
self much  unnecessary  labour.  Thus,  in  the  first  case 
described  above,  the  larva  was  full  grown  and  com- 
menced spinning  its  pear  shaped  cocoon  at  once.  On 
another  occasion  I  found  that  the  Bembex  had  taken  down 
flies  to  a  larva  that  had  already  begun  to  spin  its  oval 
cocoon  !  This  is  formed  of  silk,  with  grains  of  sand 
attached  on  the  outer  side,  and  measures  about  an  inch 
in  length. 

The  mother  Bemhex  appears  to  pass  the  night  in  the 
burrow  underground,  for  quite  often,  if  one  visits  the 
colony  early  in  the  morning,  a  Bembex  will  suddenly 
emerge  from  the  ground  at  a  spot  where  the  soil  has  not 
yet  been  disturbed  that  morning  ;  and  also  late  in  the 
evening  they  may  be  seen  going  down  into  the  burrows 
and  closing  them  behind  them.  The  male  spends  an 
idle  life  basking  on  the  hot  sand  or  darting  about  in  chase 
of  the  females,  or  sipping  honey  from  neighbouring  flower 
heads. 

The  Bembex  is  a  most  delightful  insect  to  watch,  as 
she  works  at  such  high  pressure,  and  so  efficiently  and 
quietly. 

She  has  her  enemies,  for  wherever  a  colony  is  found 
there  can  be  seen  numbers  of  little  brown  insignificant 
flies,  by  name  Idia,  who  await  a  chance  to  go  down  the 
burrow  and  deposit  their  own  eggs  on  the  flies  laid  up 
as  store  by  the  Bembex  for  her  own  offspring. 

As  was  pointed  out,  the  Bembex  may  close  her  burrow 


292  HYMENOPTERA 

when  she  leaves  it.  The  moment  she  has  gone,  up  hurries 
one  of  the  Idia  flies  and  attempts  to  get  through  the 
barrier.  Sitting  ahnost  upright  on  the  end  of  the  abdo- 
men, the  little  fly  throws  the  sand  forwards  with  quick 
movements  of  its  legs,  as  if  trying  to  burrow  backwards 
through  the  barrier.  But  I  have  never  seen  one  accom- 
plish more  than  making  a  slight  dimple  in  the  loose  sand. 
But  quite  often  the  careless  Bembex  has  gone  away  leaving 
the  burrow  open,  and  then  the  Idia  has  its  chance.  It 
hurries  up  with  such  eagerness  to  get  down  the  burrow 
that  it  may  be  seen  literally  to  tumble  head  over  heels 
as  it  scrambles  down.  There  is  need  for  hurry,  for  how 
can  it  tell  when  the  rightful  owner  will  come  back,  and 
then  it  may  meet  with  very  rough  treatment  !  But  as 
a  matter  of  fact  I  have  never  seen  Bemhex  take  any 
notice  of  the  mean  little  intruder,  though  it  may  some- 
times actually  be  met  at  the  mouth  of  the  hole  by  the 
returning  huntress.  Yet  sometimes  it  does  fall  a  victim 
to  the  sharp  sting,  for  among  flies  dug  up  from  a  burrow 
I  have  found  specimens  of  Idia. 

Small  pink  dipterous  larvae  that  are  found  in  the 
burrows  are  probably  Idia,  though  I  was  unsuccess- 
ful in  rearing  them.  It  is,  of  course,  possible  that 
they  are  not  strictly  enemies  of  Bemhex,  even  in  an 
indirect  manner,  by  devouring  the  larva's  food  ;  they 
may  merely  feed  on  debris  of  legs  and  portions  of  bodies 
left  by  the  more  fastidious  Bembex  larva. 

Every  colony  of  Bembex,  of  those  species  that  I  have 
seen,  has  had  these  little  brown  flies  in  attendance.  Some 
were  sent  to  the  British  Museum,  and  I  was  informed 
that  the  species  was  a  new  one,  and  this  habit  had  not 
previously  been  recorded  for  the  genus. 

The  first  Bembex  that  I  ever  saw  at  work  was  B.  cap- 
ensis,  which  I  found  at  Jinja  in  1910.  One  was  seen 
going  into  the  burrow  carrying  a  full  fed  Tse-tse,  whose 
shining  red,   bloated  abdomen  full  of  blood  was   quite 


BACK    OF    HOUSE   ON    KOME    ISLE,    I9I4. 


FRONT    OF    KOME    HOUSE. 


To  face  p.  292, 


BEMBEX  293 

unmistakable.  Another  burrow  that  was  opened  up 
was  found  to  contain  the  remains  of  several  small  flies 
and  of  the  Tabanid  Chrysops  brucei,  besides  two  Tahanus 
thoracinus.  The  fact  that  Bembecidae  prey  upon  Tabanidae 
is  well  known,  but  not,  I  think,  that  they  prey  upon 
Glossina,  the  Tse-tse  fly. 

In  March  1912,  I  saw  the  following  curious  incident 
on  Bugalla  Isle,  where  I  had  found  a  colony  of  Bembex 
ugandensis.  One  was  seen  to  come  out  of  her  burrow, 
and  soon  returned  with  a  small  fly,  went  down,  quickly 
came  out  and  flew  away,  leaving  the  burrow  open. 

There  now  appeared  on  the  scene  a  medium  sized 
fossor  of  quite  a  different  type,  with  the  black  and  orange 
"  Lycoid  "  colouring.  To  my  great  surprise  the  stranger, 
after  hunting  about,  found  the  burrow  and  went  straight 
down  !  Then  she  came  out  again  and  stood  waiting  at 
the  mouth  on  the  heap  of  loose  sand,  but  soon  went  in 
again  and  stood  with  her  head  blocking  up  the  entrance. 

The  Bembex  now  came  back  carrying  a  fly  of  some 
kind,  and  attempted  to  go  down  the  burrow,  but  on 
meeting  the  intruder  flew  off  in  a  great  fluster,  dropping 
her  prey.  She  soon  came  back,  tried  again,  and  again 
flew  off,  nonplussed.  The  third  time  she  managed  to 
get  in,  and  I  listened  for  the  sound  of  an  underground 
battle,  but  heard  nothing. 

However,  in  a  few  seconds  the  stranger  came  out, 
not  at  all  hurriedly,  and  flew  away,  but  soon  came  back 
and  went  in  again  while  the  Bembex  was  still  there, 
then  came  out  again  and  stood  at  the  mouth.  I  then 
incautiously  frightened  it  away  by  moving. 

The  Bembex  now  came  out  and  flew  away,  and  the 
intruder  came  back  and  stood  inside  the  burrow  again 
with  its  head  at  the  entrance.  After  a  while  it  flew 
away,  but  again  came  back  and  stood  on  the  heap  of 
loose  sand  outside  the  entrance,  then  buzzed  round  for 
a  while  and  finally  flew  away. 


294  HYMENOPTERA 

I  tried  to  dig  up  the  contents  of  the  burrow,  but  failed, 
and  am  at  a  loss  to  know  what  is  the  explanation  of  the 
intrusion.  Unfortunately  the  Lycoid  fossor  was  not 
caught  for  identification. 

Another  family  of  Fossores  is  the  Sphegidae,  which 
contains  insects  of  very  varied  size  and  habits,  although 
they  all  agree  in  storing  up  paralysed  insects  or  spiders 
for  their  young.  The  species  of  prey  chosen  by  Sphegids 
differ  greatly  ;  some  choose  spiders,  many  more  grass- 
hoppers or  crickets,  and  many  others  the  smooth  bodied 
caterpillars  of  Noctuid  or  Geometrid  moths,  but  never 
hairy  caterpillars  such  as  those  of  Arctiidae  or  Lymantridae, 
though  I  have  seen  one  species  taking  a  pilose  Lycaenid 
caterpillar  into  its  burrow.  If  the  species  selected  is  of 
small  size,  a  number  must  be  collected,  but  very  often 
a  single  individual  furnishes  all  the  food  that  a  Sphegid 
larva  requires. 

Although  they  all  belong  to  the  natural  group  Fossores, 
the  Sphegidae  do  not  all  dig  in  the  ground. 

A  dead  bough  that  contained  a  nest  of  a  large  Carpenter 
bee  was  also  used  by  a  large  black  Sphegid  for  its  brood. 
A  tunnel  about  half  an  inch  in  diameter  had  been  exca- 
vated, and  the  mouth  was  stopped  up  by  little  pieces 
of  wood  and  lichen.  It  penetrated  perpendicularly  into 
the  wood  for  about  an  inch  and  then  turned  sharply  to 
the  right  and  ran  longitudinally  about  four  inches.  At 
the  end  was  a  collection  of  the  remains  of  some  half- 
dozen  small  Locustidae,  and  a  cocoon  about  an  inch  and 
a  half  long,  formed  of  an  outer  silky  and  an  inner  papery 
layer.  Inside  the  cocoon  was  the  larva,  and  six  small 
larvae,  probably  Diptera,  which  were  presumably  indirect 
parasites  like  Idia.  Beyond  the  cocoon  the  passage  was 
directed  towards  the  centre  of  the  bough,  then  turned 
to  the  left  for  two  inches,  and  eventually  opened  to  the 
exterior  below  the  original  opening.  This  second  orifice 
was   not   stoppered.     It   is   much   to   be   regretted   that 


SPHEGIDAE  295 

the  species  was  not  identified,  since  this  method  of  nesting 
is  very  unusual  for  a  fossor. 

Another  very  unusual  nesting  place  was  found  to  be 
used  by  a  specimen  of  Sphex  (Isodonta)  pelopaeiformis. 
This  was  in  the  open  end  of  the  hollow  stem  of  a  broken 
reed.  The  Sphex  was  seen  going  there  carrying  a  small 
piece  of  wood,  and  I  found  she  had  finished  provisioning 
her  nest  and  was  stopping  the  hole  at  the  end  of  the  stem. 
There  were  two  collections  of  stored  up  Locustidae,  belong- 
ing to  species  of  very  different  types  ;  all  were  young, 
and  in  some  the  wings  had  not  begun  to  grow.  There 
were  nine  in  one  chamber  and  six  in  the  other,  the  two 
being  separated  by  a  partition  partly  of  earth,  partly 
of  some  soft  brown  substance  of  almost  woolly  texture 
whose  origin  was  unknown.  One  Locustid  of  each  col- 
lection had  the  Sphex's  egg  affixed  to  it  on  the  under 
surface  close  behind  the  head.  It  is  very  interesting  that 
this  fossor,  while  abjuring  the  earth  as  a  nesting  place, 
still  made  use  of  it  as  material  wherewith  to  form  a 
partition  between  the  two  collections  of  prey. 

Another  Sphegid  with  nesting  habits  unusual  among 
this  group  is  the  extremely  common  and  widespread 
Sceliphron  spirifex,  familiar  in  every  house  ;  it  is  even 
found  in  South  Europe. 

This  rather  elegant  black  and  canary-yellow  species, 
with  long  limbs  and  narrow  pedicle  to  the  abdomen,  is 
classed  as  a  "  Mud  wasp  "  by  the  annoyed  housewife, 
from  its  habit  of  building  a  collection  of  earthen  cells 
in  any  convenient  nook,  such  as  the  fold  of  a  curtain, 
the  corners  of  open  boxes,  the  back  of  a  book,  and  such- 
like places.  Like  most  Sphegidae,  this  energetic  worker 
emits  a  curious  note  when  working — a  quavering,  high- 
pitched  buzz  rising  and  falling  slightly  that  is  presumably 
made  by  quick  vibrations  of  the  wings  as  they  lie  upon 
the  back.  There  are  few  houses  in  which  this  sound 
cannot  be  heard  coming  from  some  obscure  corner.     The 


296  HYI^IENOPTERA 

completed  cell  is  about  an  inch  and  a  half  long,  thick 
walled  and  smooth,  with  an  internal  calibre  of  an  ordinary 
lead  pencil.  It  is  stuffed  full  of  small  paralysed  spiders, 
on  one  of  which  the  elongated  egg  has  been  deposited. 

The  Sceliphron  obtains  its  building  material  from  a 
spot  where  the  earth  is  damp,  such  as  the  edge  of  the 
lake,  and  gathers  up  in  her  mandibles  a  pellet  about  the 
size  of  a  sweet-pea  seed.  With  this  she  at  once  flies  back 
to  the  chosen  spot,  and  plasters  it  on  to  one  end  of  the 
commenced  cell,  smoothing  it  with  her  mandibles  very 
deftly,  singing  the  while  her  high-pitched  working  song. 

No  sooner  has  she  used  up  the  pellet  than  back  she 
goes  for  another,  until  the  cell  is  completed,  save  for  the 
closing  of  one  end,  which  is  done  when  the  stock  of  spiders 
has  been  brought. 

On  Kerenge  Isle,  where  spiders  were  exceedingly 
abundant,  Sceliphron  was  also  plentiful,  and  my  grass 
hut  was  a  very  favourite  nesting  place,  so  that  the  high- 
pitched  song  of  the  worker  was  heard  all  day  long.  While 
sitting  writing  one  morning  I  timed  the  journeys  of  one 
individual,  noting  the  moment  when  she  reappeared  with 
a  fresh  pellet  of  moist  building  material,  which  she  applied 
without  waste  of  time,  flying  away  again  immediately  to 
bring  another  pellet. 

The  following  are  the  times  noted  :  8- 45,  8- 48,  8- 50^, 
8-57i  91,  9-6,  9-8i,  912J,  917,  923^  927,  930,  9-33J, 
9-36^  9-39^  9-41J,  944^,  9-47.  After  this  she  did 
not  reappear  for  half  an  hour,  and  I  went  out. 

The  average  time  taken  to  fly  from  the  nest  to  the 
lake  shore,  collect  a  mud  pellet,  bring  it  back,  and  build 
it  on  to  the  nest  was  36  minutes,  the  shortest  being  two 
minutes,  the  longest  seven. 

Although  the  cells  are  often  built  singly,  they  may 
be  aggregated,  being  built  one  alongside  the  other,  so 
that  a  single  mass  the  size  of  a  small  fist  may  be  formed, 
comprising  eight  or  ten  cells,  each  stuffed  with  spiders. 


SCELIPHRON  AND   ITS  PREY 


297 


It  is  quite  extraordinary  to  think  that  all  that  material, 
weighing  perhaps  half  a  pound,  has  been  brought  by 
one  insect. 

The  destruction  of  spiders  wrought  by  one  Sceliphron 
in  providing  for  a  future  generation  is  also  surprising. 

On  Kerenge  Isle  I  counted  the  number  taken  from 
twenty -nine  cells.  In  the  following  table  a  cell  is  indi- 
cated by  a  serial  number,  and  all  cells  found  attached 
together,  i.e.  built  by  one  individual,  are  indicated  by 
the  same  letter. 


lA 
2A 
3A 
4B 
6B 
6C 
7C 
SD 
9D 
lOD 


} 


..       6 

IID 

8 

21G 

7 

12E 

.      12 

22G 

8 

13E 

8 

23H 

. .     25 

14F 

8 

24H 

16F 

8 

25K 

1 

16F 

5 

26K 

7 

17F 

4 

27K 

5 

18F 

6 

28K 

..12 

19 

.      12 

29K 

..      14 

20 

.        5 

7 
9 
11 
14 
12 
15 
11 
11 
19 


The  average  number  of  spiders  in  a  cell  was  9-3,  the 
minimum  one,  the  maximum  nineteen.  The  variation 
in  the  amount  of  food  stored  up  is  considerable,  even  in 
cells  constructed  by  one  Sceliphron.  Thus  No.  6  had  only 
a  single  spider,  very  little  larger  than  one  of  the  seven 
in  cell  No.  7.  The  spiders  are  usually  of  a  number  of 
different  species,  but  the  twelve  in  cell  No.  19  appeared 
to  be  the  same. 

The  destruction  of  spiders  by  Sceliphron  must  be  con- 
siderable. Supposing  that  ten  cells  are  completed  during 
the  lifetime  of  one  individual,  it  will  have  accounted  for 
about  ninety  spiders. 

Sceliphron  itself,  however,  is  victimized  by  a  large 
"  Ichneumon  "  fly  of  the  same  black  and  canary -yellow 
hues  presenting  a  remarkable  likeness  to  its  victim, 
especially  when  seen  on  the  wing  at  a  little  distance. 
Two- winged  flies   (Tachinidae)  can  also  be  reared    from 


298  HYMENOPTERA 

Sceliphron  cells,  but  they  are  probably  indirect  parasites, 
their  larvae  feeding  upon  the  spiders  and  not  upon  the 
Sceliphron  larvae,  which  thus  die  of  hunger. 

A  smaller  species  of  Sceliphron  makes  cells  somewhat 
similar  to  the  mud  nests  built  by  S.  spirifex,  but  they 
are  placed  upon  grass  stems  and  are  of  more  delicate 
structure,  being  composed  of  some  light  friable  material 
mixed  with  fibrous  substance.  These  nests  were  common 
also  on  Kerenge  Isle,  and  were  filled  with  spiders. 

The  great  majority  of  Sphegidae,  however,  are  true 
fossors — that  is,  they  excavate  burrows  into  which  the 
paralysed  prey  is  put. 

Since  a  Sphegid  having  once  stocked  the  burrow  pays 
no  more  attention  to  it,  there  is  no  need  for  it  to  work 
like  Bembex  in  loose  light  soil ;  indeed,  the  firmer  it  is 
the  better  they  seem  to  like  it,  and  often  may  be  seen 
working  on  the  hard  surface  of  a  trodden  pathway. 

The  methods  of  a  Sphegid  differ  somewhat  from  those 
of  a  Bembex.  The  earth  cannot  be  removed  by  mere 
scratching,  but  needs  to  be  excavated  by  "  tooth  and 
nail." 

An  Ammophila,  for  instance,  having  found  a  suitable 
site,  commences  to  scrape  together  a  little  of  the  loose 
soil  on  top,  which  she  holds  between  her  front  feet  and 
head  and,  having  walked  backwards  a  few  inches,  deposits 
it  with  a  little  buzz  of  satisfaction  and  returns  for  another 
armful.  Presently  the  soil  is  found  firmer,  and  she  sets 
to  work  with  her  powerful  mandibles  to  loosen  it,  some- 
times bringing  up  portions  in  her  jaws.  The  work  pro- 
ceeds with  rapidity  until  the  hole  descends  vertically  to 
such  a  depth  that  she  disappears  from  view. 

She  seems  to  be  on  springs,  so  full  of  life  and  energy 
is  she  ;  it  is  often  extremely  curious  to  note  how  rapidly 
she  shoots  out  from  the  burrow  backwards,  drops  her 
load,  and  plunges  headlong  down  the  hole  again  as  if 
drawn  by  a  piece  of  elastic  attached  to  the  bottom  thereof. 


AMMOPHILA  299 

Occasionally  a  piece  of  stone  defies  removal,  and  a  pro- 
longed and  angry  buzzing  from  beneath  the  surface 
attests  her  efforts  to  dislodge  it  with  her  mandibles,  but 
presently  she  works  it  loose  and  comes  up  with  it. 

At  last  all  is  ready,  and  she  proceeds  to  cover  the  mouth 
of  the  burrow  before  going  off  to  seek  the  prey  where- 
with to  fill  it.  Pieces  of  stone  of  small  size  are  selected 
and  wedged  together  so  as  to  block  the  entrance,  and 
with  her  back  to  it  she  scratches  a  little  loose  earth  over 
the  stones  and,  after  a  final  careful  examination,  flies 
away. 

Now  you  may  see  her  quartering  the  ground  for  the 
caterpillar,  grasshopper  or  other  insect  which  she  needs  ; 
wings  flicking  and  antennae  quivering,  she  runs  about 
eagerly  searching  until — pounce  ! — she  has  found  one 
and  stung  it,  and  it  lies  helpless  on  the  ground,  with 
limbs  slightly  twitching. 

Picking  it  up  by  her  mandibles,  unless  it  is  too 
large,  she  walks  with  it  back  to  her  hole,  keeping  a 
marvellously  straight  course  over  all  kinds  of  obstacles, 
even  climbing  with  it  up  perpendicular  rock  faces,  until 
after  much  effort  she  arrives  at  the  site  of  the  burrow. 
This  is  quite  indistinguishable  from  the  surrounding  soil, 
but  she  knows  it,  for  did  she  not  herself  take  pains  to 
conceal  it  before  she  left  it  ?  The  precious  burden  is 
put  down,  and  the  barricade  that  closes  the  burrow  is 
removed.  Down  she  goes  head  first,  and  presumably, 
after  making  sure  that  all  is  well,  turns  round  in  the 
chamber  at  the  bottom,  for  almost  immediately  her 
head  reappears  and  she  seizes  the  prey  and  drags  it  down. 
After  a  very  brief  interval,  during  which  the  egg  is  laid, 
she  reappears  and  at  once  sets  to  work  to  fill  up  the 
burrow.  Standing  with  her  head  away  from  the  open 
mouth,  she  vigorously  scratches  the  loose  earth  back- 
wards into  it  with  sure  aim.  But  to  make  a  good  job 
of  it  something  more  is  required,  so  she  picks  up  pieces 


800  HYMENOPTERA 

of  stone  and  puts  them  down  the  hole,  and  then  proceeds 
to  ram  it  all  down  in  a  most  workmanlike  manner. 

Firmly  gripping  the  lips  of  the  hole  with  her  middle 
and  hind  legs,  she  launches  herself  with  great  force  against 
the  loose  earth,  using  the  front  of  her  broad  head  as  a 
battering  ram,  and  making  the  loud  buzz  wherewith  a 
great  effort  is  signalized.  At  length  the  burrow  is  filled 
up  flush  with  the  surface,  and  it  only  remains  to  con- 
ceal the  fact  that  the  spot  is  in  any  way  different  from 
the  surrounding  terrain.  Small  stones  are  scattered  over 
the  surface,  a  little  loose  dust  is  scratched  about,  and 
the  energetic  Ammophila  flies  off  to  refresh  herself  on 
a  neighbouring  flower  head  before  commencing  to  excavate 
a  fresh  burrow  elsewhere.  Unlike  the  Bembex,  she  will 
never  visit  her  burrow  again  ;  it  has  been  adequately 
stocked  with  food  once  and  for  all. 

The  above  is  a  general  description  of  the  methods 
adopted  by  the  majority  of  Sphegidae,  and  we  will  turn 
now  to  another  great  family  of  fossors,  the  Pompilidae, 
which  is  broadly  characterized  by  rather  longer  limbs, 
and  by  the  fact  that  they  hunt  spiders  only.  In  essentials 
they  work  in  the  same  manner  as  the  Sphegidae,  but  so 
far  as  I  can  remember  they  work  quietly,  and  never 
make  the  excited  buzzing  so  characteristic  of  Sceliphron 
spirifex  and  other  Sphegidae. 

But  when  it  comes  to  the  filling  up  of  the  stocked 
burrow  there  is  an  important  difference  in  the  manner 
of  working,  which  I  do  not  think  has  been  sufficiently 
appreciated. 

As  described  above,  a  Sphegid  uses  the  front  of  her 
broad  head  as  a  battering  ram  wherewith  to  press  down 
the  loose  earth  ;  but  Pompilidae  invariably  use  the  end 
of   the  abdomen. 

Sometimes  the  insect  stands  in  the  mouth  of  the  hole 
and  quietly  presses  down  the  soil  in  the  burrow,  but  one 
specimen  that  I  saw  threw  her  body  into  such  quickly 


POMPILIDAE  301 

repeated  movements  that  her  outline  became  blurred, 
and  she  reminded  one  of  the  rapid  oscillations  of  a 
pneumatic  hammer.^ 

Perhaps  Pompilidae  do  not  use  the  front  of  the  head 
because  it  is  less  broad  and  flat  than  in  Sphegidae,  and 
therefore  does  not  form  such  an  efficient  rammer  ;  but 
the  difference  is  extremely  remarkable. 

The  Pompilidae  are  most  typically  aposematic  insects. 
Many  are  of  intense  blue-black  with  shining  bluish  or 
greenish  black  wings,  often  set  off  by  canary-yellow 
antennae.  The  sting  inflicts  a  very  painful  wound,  but 
they  do  not  use  it  unless  molested,  and  may  be  watched  with 
perfect  immunity  so  long  as  they  are  not  roughly  handled. 

It  is  difficult  to  conceive  a  more  conspicuous  insect 
than  one  of  these  fine  creatures  as  it  sails  through  the 
air  with  its  long  legs  hanging  down.  Yet  according  to 
some  of  the  American  naturalists  these  insects  are  con- 
cealed by  resemblance  to  their  surroundings. 

In  that  case  it  is  difficult  to  explain  one  of  the  most 
striking  characteristics  of  these  large  Pompilidae,  namely, 
the  extraordinarily  noisy  flight,  which  is  often  a  loud 
rattling  or  clicking  noise  audible  before  the  insect  is  seen, 
and  reminding  one  of  a  badly  made  piece  of  clockwork. 

If  a  Pompilid  is  really  concealed,  what  is  the  meaning 
of  this  noise  which  at  once  directs  attention  to  it  ? 

If,  on  the  other  hand,  these  insects  are  really  highly 
conspicuous,  as  I  think,  the  loud  noise  is  merely  an 
adjunct  to  their  aposematic  colouration,  and  serves  still 
further  to  advertise  their  owner's  unpleasantness. 

Many  times  have  I  seen  my  pet  monkeys'  attention 
caught  by  the  noise  of  one  of  these  formidable  insects 
on  the  wing,  and  they  would  turn  their  heads  to  the 
direction  from  which  it  came,  and  watch  the  Pompilid 
when  it  came  into  sight  with  the  most  careful  attention, 
being  evidently  anxious  to  avoid  it  when  it  drew  near. 

^  Batozonus  fuUginosus.     See  Proc.  Ent.  Soc.  Lond.,  1917,  p.  Ix, 


302  HYMENOPTERA 

This  *'  aposematic  noise  "  is  entirely  in  keeping  with, 
and  explicable  by  the  same  means  as,  the  conspicuous 
appearance  of  the  insect,  which  is  thus  enabled  to  appeal 
to  more  senses  than  one.  But  if  the  Pompilid  is  con- 
cealed, then  one  explanation  is  required  for  its  colour 
and  another  for  its  noisy  flight,  though  it  is  difficult  to 
imagine  what  explanation  of  the  latter  could  be  given. 
I  have  suggested  elsewhere  ^  that  there  is  an  analogous 
example  among  birds  in  the  case  of  the  large  black  and 
white  "  E'nga-nga  "  hornbill,  whose  wings  make  an  extra- 
ordinary roaring  noise  as  it  beats  them,  or  sails  with 
them  outspread  through  the  air,  often  at  the  same  time 
calling  attention  to  itself  by  its  loud  raucous  cry. 

It  has  been  mentioned  in  the  case  of  the  Bembecidae 
that  they  have  enemies  in  certain  flies,  and  the  same 
holds  good  with  Sphegidae  and  Pompilidae. 

The  golden  moment  for  the  enemies  of  these  fossors  is 
when  they  have  arrived  with  their  burden  at  the  mouth 
of  the  burrow  and  leave  it  outside  while  they  go  down. 
The  attendant  fly  can  then  dart  down  and  deposit  its 
own  egg  up'on  the  prey  while  the  fossor  is  busy,  and  that 
it  does  so  is  evidenced  by  the  fact  that  on  grasshoppers 
taken  out  of  the  burrows  of  the  little  Sphex  marginatus 
I  found  dipterous  larvae  which  became  flies  of  a  species 
unknown  to  the  British  Museum,  but  alUed  to  the  Milto- 
gramma  described  by  Fabre.  It  is  rather  interesting 
that  whereas  most  fossors  seem  to  take  little  notice  of 
other  insects  while  they  are  at  work,  Sphex  marginatus 
is  extremely  suspicious  of  any  intruders  on  its  privacy, 
and  charges  fiercely  with  open  mandibles  at  even  the 
smallest  ant  that  draws  near  to  its  burrow,  much  to  the 
dismay  of  the  quite  inoffensive  ant  !  If  the  trespasser 
does  not  at  once  withdraw,  the  Sphex  makes  threatening 
movements  as  if  about  to  sting,  turning  the  tip  of  her 
abdomen  forwards  between  her  legs. 

»  p.  168. 


MUTILLIDAE  BEES  303 

Another  family  of  fossors,  the  Scoliidae,  has  been  men- 
tioned because  they  save  themselves  a  great  deal  of 
labour  by  searching  out  the  food  for  their  larvae  and 
laying  an  egg  on  it  in  situ. 

They  are  interesting  also  from  another  point  of  view, 
because,  of  all  Hymenoptera,  they  have  the  quietest  flight  ; 
even  the  largest  specimens  produce  a  barely  audible  hum, 
thus  contrasting  greatly  with  Pompilidae.  They  are 
usually  rather  solidly  built,  hairy  insects,  sometimes 
black,  sometimes  reddish  or  yellowish  in  colour. 

Lastly,  there  are  the  Mutillidae,  which  will  only  be 
mentioned  on  account  of  their  scarcity  on  the  islands. 
It  seems  that  forested  country  and  a  damp  climate  are 
not  so  suitable  to  them  as  the  more  open  bush  country 
with  regular  dry  seasons  such  as  occurs  in  much  of  ex- 
German  East  Africa,  where  I  found  Mutillidae  far  more 
abundant  than  on  the  islands.  They  are  remarkable 
among  Hymenoptera  for  the  complete  absence  of  wings 
in  the  females,  which  are  often  mistaken  for  ants  as  they 
run  quickly  over  the  ground.  A  species  of  Methoca  was 
obtained  which  was  not  in  the  British  Museum  collection  : 
the  few  African  species  that  are  known  of  this  genus 
had  previously  only  been  obtained  from  south  of  the 
river  Limpopo. 

Regarding  Bees  I  have  little  to  say.  The  very  hand- 
some large  "  Carpenter  bees  "  {Xylocopidae) , .  which  in 
the  tropics  take  the  place  of  our  "  Bumble  bees  " 
at  home,  are  plentiful  enough,  and  may  often  be  seen 
visiting  the  large  yellow  flowers  of  ambatch  trees.  A 
particularly  handsome  large  one  is  covered  with  bright 
golden  brown  hair  ;  this  is  the  male  of  a  species  whose 
female  is  black  and  white.  Their  burrows  in  dead 
trees  are  commonly  seen.  The  natives  call  them 
"  Buvumira,"  which  is  quite  descriptive  of  a  large 
buzzing  insect. 

A  smaller  bee  {Crocisa  meripes)  presents  a  great  con- 


304  HYMENOPTERA 

trast  to  these  furry  fellows,  as  its  integument  is  hairless, 
and  brightly  coloured  sky  blue  and  black, 

I  do  not  know  where  Crocisa  nests,  but  it  has  a  remark- 
able habit  of  passing  the  night  in  the  open  on  a  grass 
stem,  its  mandibles  firmly  clasped  round  the  stem,  and 
its  legs  tucked  up  against  the  body,  so  that  the  insect, 
supported  only  by  the  grasp  of  its  mandibles,  projects 
obliquely  from  the  stem.  They  may  often  be  found  dead 
in  this  position. 

Sometimes  several  will  affix  themselves  thus,  one 
below  the  other,  and  the  stem  may  be  picked  and  carried 
about  without  disturbing  the  bees.  Another  species 
{Coeliaxis  carinata)  has  the  same  resting  habit.  The 
islands  are  singularly  blest  in  the  absence  of  minute, 
stingless,  but  very  annoying  bees  (Melipona),  commonly 
known  as  "  Sweat  bees,"  from  their  habit  of  settling  on 
one's  bare  skin  and  licking  up  the  perspiration.  If  they 
would  only  settle  quickly  one  would  not  object  so  strongly, 
but  they  spend  a  long  time  dancing  about  in  front  of 
one's  face  under  the  brim  of  one's  hat ;  when  they  do 
settle  they  cause  an  intolerable  tickling. 

Though  they  have  lost  their  sting  they  are  very  possibly 
still  protected,  for  if  one  is  squashed  by  a  blow  it  has 
an  unpleasant  acrid  odour.  I  first  made  their  acquaint- 
ance on  active  service,  and  soon  learnt  to  give  thanks 
that  the  islands  did  not  support  them  ! 

Like  the  Mutillidae  they  seem  to  prefer  more  open, 
drier  country ;  hence  the  thirst  which  leads  them  so 
eagerly  to  suck  up  moisture  from  one's  skin. 


P'LY    BOYS     CAMP   ON    KOME    ISLE,    I9I4. 


SERVANTS'    HUTS    ON    KOME    ISLE,    I9I4. 


To  face  p.  304, 


CHAPTER  XIII 
SUNDRY  INSECTS 

COLEOPTERA. 

Beetles  were  not  systematically  collected  on  the  islands, 
so  that  there  is  not  so  much  to  be  said  about  them  as 
about  Lepidoptera. 

The  first  interesting  specimen  that  was  met  with  on 
the  lake  shore  was  a  new  species  of  Coprid,  which  Mr. 
Arrow  informed  me  was  quite  unlike  anything  in  the 
British  Museum.  I  was  watching  a  column  of  the 
"  Safari "  ant  (Dorylus)  moving  from  one  camp  to 
another,  carrying  their  pupae  with  them,  and  saw  this 
flat,  black,  highly  polished  beetle  running  in  the  column 
among  the  ants,  who  took  not  the  slightest  notice  of  it. 
That  it  did  not  belong  to  them  was  improbable,  for  it 
took  the  greatest  care  to  remain  in  the  column,  and 
these  ferocious  ants  most  strongly  resent  the  presence 
of  any  stranger  among  them.  It  is  interesting  to  find 
that  these  dread  hunters  have  their  familiars.  Possibly 
the  larva  acts  as  a  useful  scavenger  in  their  nests,  as  does 
the  larva  of  the  Rose  beetle  in  nests  of  other  ants. 

While  at  Jinja  in  1910,  I  watched  with  interest  the 
behaviour  of  some  large  polished  green  Coprids  engaged 
in  making  their  balls  from  the  recent  droppings  of  some 
grazing  animal. 

When  I  first  came  up  one  had  almost  finished 
making  its  ball.     When  it  was  finished  the  beetle  pressed 

21  30» 


806  SUNDRY   INSECTS 

the  material  together  with  its  front  legs  and  then  very 
cleverly  rotated  it  on  one  spot,  lying  almost  underneath 
it,  so  as  to  get  a  firm  coating  of  earth  on  it  ;  it  then 
trundled  the  ball  away.  Soon  other  beetles  arrived  on 
the  wing,  dropping  quite  near  to  their  objective  and 
eventually  crawling  to  it,  obviously  guided  by  smell. 
If  one  happened  to  meet  another  when  both  were  search- 
ing for  the  dropping,  one  always  fell  in  and  followed 
behind  as  if  quite  certain  that  the  other  must  know  the 
way  !  I  watched  No.  2  make  its  ball.  The  desired 
portion  of  the  dropping  was  the  outer  part  which  had 
hardened  somewhat.  The  beetle  stays  at  one  spot  and 
reaches  towards  it  with  its  powerful  forelegs  enough 
to  make  a  ball  about  the  size  of  a  very  large  cherry. 
It  frees  it  below  by  insinuating  the  sharp  front  margin 
of  the  head  between  the  ball  and  the  mass,  and  making 
powerful  lifting  movements  of  its  head. 

No.  2,  after  making  the  ball,  did  not  for  a  long  time 
push  it  away,  but  kept  pressing  it  together  and  patting 
it,  and  finally  gave  it  a  very  smooth  coating  of  fine 
earth,  and  then  sat  resting  on  it. 

Meanwhile  others  had  arrived  (ten  altogether  came 
while  I  watched),  some  smaller  in  size.  One  of  them. 
No.  3,  apparently  desired  a  share  in  No.  2's  ball,  but 
was  driven  off,  hurled  away  by  jerks  of  the  strong  front 
legs.  Eventually  it  joined  with  another  small  one, 
No.  4,  and  these  two  very  quickly  made  a  rather  ill- 
constructed  ball  and  trundled  it  off,  No.  2  still  patting 
at  its  own. 

There  were  numerous  fights  between  the  workers,  who 
sometimes  got  mixed  and  each  took  the  other's  ball. 

These  beetles  are  eaten  by  a  species  of  Roller,  one 
of  which  when  shot  was  found  to  have  several  of  them 
inTits  stomach.  Presumably  its  powerful  bill  enables  it 
to. feed  on  such  horny  beetles,  whose  large  size  and  hard 
coat  of  mail  must  deter  smaller  birds.     Of  the  carnivorous 


BEETLES  307 

ground  beetles  I  saw  little  on  the  islands,  but  two  species 
of  Cicindelidue  (Tiger  beetles)  were  found,  which  were 
very  acceptable  to  the  British  Museum.  One,  a  pretty- 
green  species,  not  unlike  the  English  G.  campestris,  but 
larger,  was  found  abundantly  running  over  termite  hills 
on  Nsadzi  Island.  The  other  was  a  mottled  grey  species, 
found,  but  very  difficult  to  see,  on  a  stretch  of  sand  on 
Bugalla  that  had  at  one  time  obviously  been  the  lake 
shore.  The  huge  black  Cardbidae,^  common  in  Africa, 
were  never  seen  on  the  islands  ;  though  I  do  not  assert 
that  they  were  not  there,  it  seems  curious  that  they 
should  never  have  been  met  with. 

Carnivorous  water  beetles  {Dytiscidae,  Gyrinidae,  etc.) 
were  of  course  abundant  in  the  weedy  shallow  waters. 
The  readiness  with  which  they  take  to  the  wing  is  well 
known  ;  but  it  was  quite  amusing  to  note  how,  during 
a  storm  of  rain,  several  Gyrinidae  appeared  in  the  trench 
which  led  away  the  rainfall  from  the  roof  and  solemnly 
executed  their  well  known  whirligig  manoeuvres  so  long 
as  the  water  lasted,  and  when  the  storm  was  over  they 
vanished.  Large  Dytiscidae  several  times  dropped  on 
to  a  shiny  patch  of  wet  ground  during  heavy  rains, 
evidently  misled  into  thinking  it  was  a  pool. 

The  beautiful  Longicorn  beetles  were  often  met  with, 
and  one  very  abundant  green  species  of  medium  size  ^ 
had  a  very  rank  aromatic  odour,  and  my  pet  monkey 
would  not  eat  it. 

The  most  interesting  Longicorns  are  the  mimetic 
species,  and  a  very  fine  one  ^  was  abundant  on  the 
flowering  shrub  Haronga,  where  it  was  associated  with 
the  large  Lycidae  which  it  so  much  resembled.  Other 
Longicorns  mimic  the  parasitic  Hymenoptera  of  the  family 
Braconidae,  many  of  which  are  typically  aposematic  in 
appearance,  and  have  a  powerful,  rank  odour. 

^  Genus  Anthia.  ^  Phrosyne  brevicornis. 

'  Amphidesmus  analis. 


308  SUNDRY  INSECTS 

A  common  colour  scheme  for  large  Braconids  is  orange 
and  black,  and  on  Bugalla  a  Longicorn  ^  beautifully 
mimetic  of  these  was  found.  Being  long  and  narrow, 
the  beetle  has  a  shape  which  affords  a  good  basis  for 
the  resemblance.  The  orange  abdomen,  however,  does 
not  show  the  narrow  waist  of  the  Hymenopterous  model, 
to  which  the  resemblance  is  produced  by  a  portion  of 
the  side  of  the  base  of  the  abdomen  being  of  a  glistening 
white,  contrasting  strongly  with  the  remainder,  so  that 
that  part  in  a  high  light  suggests  that  it  has  been,  to 
use  Professor  Poulton's  phrase,  "  painted  out."  The 
first  specimen  that  I  found  was  a  male  which  when 
handled  strongly  curved  the  tip  of  the  abdomen  in  such 
a  way  as  to  suggest  it  was  about  to  sting,  and  actually 
protruded  a  flexible  white  viscus  which  it  moved  about 
like  a  sting.  Of  course  Braconidae  are  not  strictly 
stinging  insects,  yet  when  handled  they  will  use  the 
ovipositor  as  such.  The  Hymenopteroid  appearance  of 
the  beetle  with  its  false  sting  was  so  very  striking  that 
although  reason  told  me  it  was  a  beetle,  instinct  was 
so  strong  that  misgivings  almost  prevented  me  handling 
it,  and  I  feel  certain  the  very  great  majority  of  people 
would  have  dropped  the  beetle  in  a  panic.  On  the 
wing  the  resemblance  is  much  greater ;  both  insects 
have  a  slow,  steady  flight,  and  the  long  antennae  are 
extremely  conspicuous.  The  wings  of  the  beetle  are 
transparent  and  invisible  during  flight,  but  the  orange, 
black-tipped,  wing  covers  reproduce  the  appearance  of 
the  similarly  coloured  wings  of  the  Braconid.  Several 
smaller  species  of  Longicorns  also  very  closely  resemble 
smaller  black  and  yellow  Braconids,  so  that  even  after 
several  years  of  field  work  one  is  still  deceived  and, 
catching  an  insect  which  one  has  thought  to  be  a  Braconid, 
finds  a  beetle  in  the  net.* 

*  Dirphya,  species  near  pHnceps. 

'  This  happened  to  me  repeatedly  in   1917  in  Gennftn  East  Africa. 
See  Proo.  Ent.  Soc,  1918,  pp.  cxxxviii-cxlii. 


BEETLES  309 

Many  Braconids  are  coral  pink  and  black,  and  they 
also  are  mimicked  by  small  Longicorns.  On  Bugalla 
I  obtained  model  ^  and  mimic  ^  at  the  same  spot  and 
time,  and  also  a  small  Capsid  bug,'  equally  mimetic. 

Fireflies  are  interesting  beetles,  but,  having  read  much 
about  the  wonder  of  tropical  fireflies,  I  was  much  dis- 
appointed on  the  islands  ;  only  a  few  were  seen  at  a 
time,  belonging  to  a  species  looking  much  like  the  male 
of  the  English  glow-worm,  and  I  have  seen  a  much  better 
display  in  the  spring  on  the  Riviera. 

Wood-boring  beetles  are  a  great  nuisance  in  a  house 
constructed  of  freshly  cut  boughs  and  stems  of  trees  ; 
the  rafters  are  soon  penetrated  in  every  direction  by 
tunnels,  from  the  open  mouths  of  which  a  continuous 
stream  of  the  finest  sawdust  falls  and  soon  covers  any- 
thing left  lying  for  long  in  one  place. 

Quite  the  most  remarkable  beetle  met  with  on  the 
islands  belongs  to  the  aberrant  family  Lymexylonidae,^ 
it  several  times  appeared  in  my  hut  in  the  evening, 
flying  with  sonorous  buzz,  and  the  first  time  I  saw  it 
puzzled  me  not  a  little,  for  it  was  like  no  beetle  I  had 
ever  seen  or  heard  of  at  that  time. 

The  very  long,  thin  body  was  quite  soft  and  flexible, 
and  a  very  short  pair  of  wing  covers  entirely  failed  to 
cover  a  long  pair  of  wings  with  stout  longitudinal 
rays  so  that  they  folded  like  the  wings  of  a  grass- 
hopper, but  then  projected  far  behind  the  covers.  The 
legs  were  long  and  thin,  and  the  antennae  short,  with 
broad  flat  segments. 

Neuroptera. 

Dragon  flies  are,  of  course,  abundant  on  the  lake  shore, 
but  I  do  not  think  they  are  any  more  noteworthy  than 

^  Not  yet  identified. 

•  Dirphya,  species  near  pascoei,  Lamiidae. 

•  KolopeUis  bergrothi.  *  Atractocervs  brevicornis. 


310  SUNDRY  INSECTS 

our  beautiful  English  species.  One  fine,  abundant  species 
is  blood  red,  and  another  is  vividly  coloured  with  cobalt 
blue  and  red,  but  there  are  many  dull  species.  One  of 
these,^  the  commonest  of  all,  may  be  seen  on  the  wing 
before  sunrise  and  after  sunset,  and  on  one  occasion  on 
Kerenge  Island  I  saw  a  host  of  them  about  sunrise, 
dancing  up  and  down  in  the  air  just  as  Mayflies  do 
in  England. 

The  large  species  of  Dragon  flies  often  prey  on  the 
smaller,  as  well  as  on  bees  and  other  protected  insects. 
I  have  seen  Cacergates  preying  on  Glossina,  and  since 
both  large  and  small  Dragon  flies  are  favourite  articles 
of  food  of  the  bee-eater  Merops  super ciliosus,  the 
bionomic  relation  of  this  bird  to  the  Tse-tse  fly  is  rather 
a  complicated  one  ! 

A  curious  Neuropterous  insect  named  Bittacus  was 
attracted  to  light  several  times  on  the  islands  ;  it  is  a 
slender  light  brown  species  with  narrow  wings  and  very 
long  slender  legs.  On  the  first  occasion  I  thought  it 
was  a  Tipulid,  and  did  not  take  much  notice  until  some- 
thing about  it  made  me  look  more  closely,  and  I  saw  it 
was  not  a   "  Daddy  longlegs,"  but  had  four  wings. 

If  there  was  any  reason  for  supposing  the  TipuUdae 
to  be  protected  one  might  consider  the  Bittacus  to  mimic 
the  fly  ;  but  there  seems  no  reason  for  supposing  that 
a  resemblance  to  a  "  Daddy  longlegs  "  would  be  of  any 
benefit. 

A  remarkable  genus  of  Neuroptera  is  named  Mantispa. 
These  insects  resemble  Mantidae,  and  have  the  fore  limbs 
modified  in  the  same  manner  for  holding  the  prey,  which 
they  devour  alive.  Several  of  them  very  deceptively 
resemble  Hymenopterous  insects.  On  Kome,  one  day, 
I  saw  on  a  twig  an  insect  that  at  first  appeared  to  be 
one  of  the  abundant,  conspicuous  and  fiercely  stinging 
wasps  of   the  genus  Belonogaster.     It   was   munching   at 

^  Cacergates  leucosticta. 


MANTISPA  311 

some  insect  it  had  caught  precisely  as  the  wasp  chews 
up  caterpillars  into  pulp,  and  when  disturbed  flew  with 
it  on  to  a  neighbouring  branch.  But  the  thickness  of 
the  abdomen  caught  my  attention,  and  disclosed  the 
true  nature  of  the  insect.  The  question  may  well  be 
asked.  How  was  it  that  the  broad  wings  of  a  Neuropterous 
insect  did  not  attract  attention,  as  differing  from  the 
narrow  folded   dark  wings  of   the  wasp  ? 

When  the  Mantispa  was  at  rest  the  fore  wings 
lay  above  the  posterior  wings  and  concealed  them. 
Their  greater  part  was  absolutely  transparent  and 
hardly  noticeable,  but  the  appearance  of  the  narrow 
wings  of  the  wasps  was  produced  by  a  darkening  of  a 
narrow  strip  along  the  anterior  margin  of  the  fdre  wings, 
which  dark  strip  roughly  resembled  in  shape  the  whole 
of  the  folded  wings  of  the  wasp.^  The  Mantispa  at  rest 
held  its  wings  directed  backwards  as  does  the  wasp, 
but  not  quite  parallel  to  the  body,  so  that  they  made  a 
slightly  greater  angle  with  each  other  than  did  the 
wasp's  wings. 

In  colour  the  Mantispa  very  closely  resembled  Belono- 
gaster,  and  the  resemblance,  probably  pseudaposematic 
or  true  mimicry,  was  extraordinary,  and  would  not  be 
believed  if  one  had  only  seen  the  specimens  in  the  cabinet. ^ 

Orthoptera. 

Mantidae. — One  species,  Pseudocreobotra  ocellata,  has 
already  been  alluded  to  as  an  instance  of  Anticryptio 
colouring ;  other  equally  cryptic  grass  green  species 
were  particularly  abundant  on  certain  islands,  an  account 
of  which  was  given  in  Chapter  VI.  Sometimes  the 
curious  egg  clusters  were  very  abundant  ;  the  eggs  are 
embedded  in  a  substance  somewhat  resembling  the  crust 

1  See  also  Trans.  Ent.  Soc.  Lond.,   1902,  Part  III,  pp.  528-9. 

8  Cp.  G.  A.  K.  Marshall,  Tratis.  Ent.  Soc,  1902,  Part  III,  pp.  636-7. 


312  SUNDRY  INSECTS 

of  a  meringue,  covered  by  a  substance  resembling  parch- 
ment in  texture,  but  produced  by  the  Mantis  as  foam 
at  the  time  of  oviposition.  These  egg  masses  vary  much 
in  shape,  size  and  texture  according  to  the  species — some 
are  pure  white,  spherical,  and  about  the  size  of  a  bantam's 
egg  ;  others,  no  larger  than  a  hazel  nut,  have  an  amber 
coloured,  almost  transparent  covering,  with  a  ridge  along 
one  side  looking  like  a  seam  where  two  halves  meet. 
These  are  very  conspicuou^s,  and  may  be  seen  at  the  tips 
of  twigs,  etc.  ;  but  there  are  other  very  cryptic  forms 
of  egg  masses,  laid  along  a  twig  and  closely  adherent  to 
it,  with  rough  opaque  brown  surface.  The  freshly  hatched 
Mantids  may  sometimes  be  found  hanging  from  the 
egg  clusters  by  slender  threads,  but  I  do  not  know 
for  how  long  they  remain  thus.  Very  young  specimens 
are  often  black,  and  look  extremely  ant-like  as  they  run 
about. 

Phasmidae. — Stick  insects  found  on  the  islands  are 
small  and  not  remarkable  :  "  grass  insects  "  would  be 
a  better  name,  because  they  are  found  in  long  grass,  the 
stems  of  which  their  slender  wingless  bodies  resemble 
in  size  and  colour.  They  frequently  betray  themselves 
by  a  curious  swaying  from  side  to  side,  for  which  it  is 
difficult  to  account,  for  were  they  to  remain  quite  still 
they  would  certainly  be  invisible. 

Locustidae. — The  most  noticeable  insect  of  this  family 
was  a  slender  active  grasshopper  known  to  the  natives 
as  "  Ensenene  "  ;  about  two  inches  long,  usually  grass 
green  but  sometimes  light  brown.  These  grasshoppers 
used  to  appear  suddenly  in  great  numbers  and  could 
be  heard  faintly  chirping  in  the  grass.  As  one  walked 
along  they  took  to  the  wing  in  clouds,  and  their 
pearly  wings  flashing  in  the  sun  produced  a  curious 
resemblance  to  driven  snowflakes.  At  these  times  the 
natives  would  go  out  and  catch  large  numbers  for  eating, 
walking   through  the  long  grass  and  whistling  through 


ORTHOPTERA  313 

their  teeth  to  make  a  sibilant  noise.  They  were  prepared 
for  food  by  frying.  My  pet  monkeys  were  also  exces- 
sively fond  of  them,  and  would  eat  them  for  as  long  as 
they  were  offered,  even  until  the  overloaded  stomach 
rejected  them. 

A  ghoulish  species  of  Ephippigeridde  was  a  great 
nuisance  in  my  hut  on  Damba,  as  it  found  its  way  into 
every  box  of  food  and  quite  replaced  the  kitchen  cock- 
roach as  a  pest.  It  has  a  rotund  short  body  with  im- 
mensely long  limbs  and  antennae,  and  is  offensively 
familiar !  It  would  come  on  to  the  table  while  I  was 
dining  in  the  evening  and  stand  with  the  filamentous 
antennae  waving  in  the  air,  and  was  so  quick  that  I 
could  never  catch  it  before  it  leapt  away.  As  it 
was  a  great  nuisance  I  was  glad  to  find  that  the  egg 
cases,  like  little  portmanteaux,  were  attacked  by  a 
Chalcid  parasite,  which  laid  its  own  eggs  inside  the  case. 
One  such,  when  opened,  was  found  packed  with  rows 
and  rows  of  the  minute  white  pupae  of  the  parasite,  white, 
with  shining  black  eyes,  looking  for  all  the  world  like 
neatly  arranged  mummies.  The  male  of  this  species  has 
imperfect  wings,  and  has  not  been  heard  to  make  a 
noise. 

Another  very  large  burrowing  species  during  the  rains 
sits  at  the  mouth  of  its  burrow  making  a  continuous 
'*  shrilling  "  noise  which,  if  at  all  close,  is  quite  un- 
bearable, as  it  seems  to  make  one's  whole  head  vibrate 
in  sympathy. 

Another  Locustid  worthy  of  notice,  of  the  same  section, 
is  known  to  the  natives  as  "  Semukutu."  It  is  disliked 
very  much  by  them,  for  they  say  it  bites  and  makes  sore 
places,  and  often  show  sores  which  they  say  were  caused 
by  a  Semukutu.  When  handled  this  insect  ejects  with 
some  force  from  the  side  of  the  thorax  a  stream  of 
clear,  yellow  fluid  with  an  acrid  smell,  but  though  I  have 
handled  a  large  number  in  the  endeavour  to  collect  a 


314  SUNDRY  INSECTS 

quantity  of  the  fluid  I  have  never  suffered  in  any  way 
from  it.  No  doubt  it  would  be  excessively  unpleasant 
in  the  mouth  or  eyes  of  an  enemy.  The  Semukutu  is 
a  large,  fat,  bloated  creature  destitute  of  any  trace  of 
wings,  and  with  spiny  thorax.  Young  specimens  are 
often  greenish,  but  the  adult  is  dull  brownish  grey.  It 
is  a  very  sluggish  insect,  and  freely  exposes  itself  as  it 
crawls  heavily  about. 

Acrididae. — Large  and  powerful  grasshoppers  of  this 
family,  species  of  Cyrtacanthacris,  are  known  as  "  Ama- 
jansi  "  to  the  Baganda.  Some  of  them  are  several  inches 
long,  and  were  apparently  much  esteemed  as  food  by 
the  monkeys.  They  were  not  noticeably  abundant  on 
aU  the  small  islands  visited,  but  seemed  to  be  so  on 
Kerenge,  where  the  beautiful  bright  blue  kingfisher  that 
feeds  on  them  was  much  in  evidence. 

Blattidae. — Cockroaches  of  many  species  were  common 
among  dead  leaves  in  the  forest,  but  one  saw  little  of 
them  except  when  the  "  Safari  ant  "  was  out  hunting. 
Then  the  unfortunate  cockroaches,  driven  from  their 
lairs,  rushed  hither  and  thither  in  frantic  desperation, 
and  in  such  a  state  of  panic  that  they  often  tumbled 
head  over  heels,  and  the  more  easily  fell  a  prey  to  the 
host  of  ants,  which  at  once  tore  them  to  pieces.  Some 
curious  species  may  be  found  half  buried  in  loose  dry 
earth  at  the  base  of  trees  ;  absolutely  wingless,  they 
look  much  like  huge  woodlice. 

Dermaptera. 

The  earwig  family  was  not  at  all  well  represented  on 
the  islands,  much  to  my  surprise,  for  there  seemed  to 
be  ideal  conditions  for  them.  I  thought  at  the  time 
that  perhaps  this  was  the  rule  in  equatorial  Africa,  but 
later  modified  this  view  when  on  active  service  in  German 
East  Africa,   where  earwigs  were  found  extraordinarily 


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; 

cook's  uut  (left)  and  kitchen  on  bugalla. 
Cook  on  right.     The  water  boy  on  the  left  developed  sleeping  sickness. 


HEAD    KoV    (A    SWAIIII  II    A  Nl  >    ^I-.i;(jN1i    liuV    (mL'GANDA)    ON    RIGHT. 
Their  wires  had  come  out  for  a  brief  visit. 


To  face  p.  314. 


FLIES  315 

abundant  in  some  parts  of  the   country.     So   that  the 
islands  would  appear  to  be  unfavourable  to  them. 

One  large  species  was  found  on  Damba  under  a  stone 
at  the  very  water's  edge,  so  that  the  tiniest  ripple  must 
have  surrounded  it. 

DiPTERA. 

The  most  important  fly  on  the  islands,  namely  Glossina 
palpalis,  has  had  a  chapter  to  itself.  Other  biting  flies 
{Tabanidae)  were  less  common  on  the  islands  than  on 
the  mainland,  but  T.  variabilis  a  small  black  and  white 
species,  and  Chrysops  brucei  were  occasionally  seen,  with 
one  or  two  species  of  Hcematopota. 

Mosquitoes,  of  course,  were  to  be  reckoned  with,  and 
they  were  particularly  abundant  on  Damba  Island, 
perhaps  because  it  was  covered  with  low  lying  forest. 
But  the  Anophelines,  carriers  of  malaria,  were  so 
scarce  that  the  numbers  of  times  one  was  seen  could 
be  counted  on  the  fingers,  so  that  the  health  of  the  party 
was  excellent.  The  Simuliidae,  or  "  Buffalo  gnats,"  have 
been  alluded  to  as  particularly  troublesome  on  certain 
islands  when  rain  was  threatening  ;  they  frequent  rocky 
open  shores,  and  when  abundant  render  such  spots  un- 
approachable. The  species  found  on  the  islands  was 
not  the  same  as  the  one  I  had  previously  met  at  Jinja, 
S.  damnosum,  called  "  Embwa  "  by  the  natives ;  the 
island  Simulium  is  smaller  and  rather  prettily  coloured 
with  golden  pubescence.  Both  leave  a  severe  burning 
and  itching  sensation,  but  whereas  S.  damnosum  attacks 
particularly  the  lower  extremities,  the  island  species 
makes  for  one's  head  and  neck,  and  especially  the  ears. 

The  parasitic  Tachinidae,  which  lay  their  eggs  on  the 
surface  of  living  insects,  have  been  briefly  alluded  to  as 
enemies  of  "  protected  "  insects. 

On  one  occasion  a  species  was  observed  in  the  act  of 
oviposition. 


316  SUNDRY  INSECTS 

On  the  minute  island  Lula,  several  colonies  of  very 
hairy  caterpillars,  of  the  family  Eupterotidae,  were  seen 
on  trunks  of  trees.  Near  one  colony  was  a  large  Tachinid 
fly,  and  the  caterpillars,  close  together,  seemed  to  be 
aware  of  her  presence,  for  they  moved  uneasily  ;  but 
the  fly  moved  as  they  moved,  sidling  about  in  a  very 
amusing  manner  so  as  always  to  face  the  caterpillars. 
She  endeavoured  to  find  one  that  was  not  moving, 
and  then  approached  the  head  from  in  front.  The  long 
hairs  of  the  caterpillar  projected  from  all  parts  except 
the  head,  so  as  to  form  a  chevaux  de  frise,  but  opposite 
the  head  there  was  a  small  gap  in  the  barrier.  The  fly, 
having  approached  as  close  as  she  could,  raised  herself 
up  on  her  anterior  legs  and  protruded  forwards,  beneath 
herself,  an  enormous  ovipositor  whose  tip  projected  in 
front  of  her  head.  The  egg  was  laid  in  a  very  brief  instant 
on  or  near  the  head  of  the  caterpillar,  but  sometimes 
the  fly  was  unable  to  reach  its  head,  and  then  had  to 
wait  until  the  larva  was  near  enough  for  her  ovipositor 
to  reach  between  the  long  hairs  so  as  to  deposit  an  egg 
on  the  flank  of  the  larva. 

It  was  a  most  interesting  and  instructive  proceeding, 
illustrative  of  the  adaptation  of  one  enemy  (the  fly)  to 
meet  a  condition  in  its  victim  probably  directed  against 
other  enemies  (birds).  It  was  noted  that  the  fly  laid 
its  eggs  fortuitously  on  any  larva  that  presented  itself, 
so  that  one  received  many  eggs  but  others  none.  This 
might  quite  well  lead  to  some  of  the  offspring  of  the  fly 
receiving  insufficient  nourishment  and  being  stunted  in 
growth  or  failing  to  develop.  One  sometimes  meets  the 
opposite  condition,  when  too  few  ova  have  been  deposited, 
and  the  parasites  have  not  damaged  the  vital  parts 
of  their  host.  I  once  reared  a  single  Tachinid  fly  from 
an  Arctiid  larva  which  eventually  produced  a  perfect 
moth  ! 

Asilidae  or  Robber  flies  were  often  met  with  at  the  very 


FLIES  817 

margin  of  the  forest  where  it  abuts  on  open  grass  land  ; 
others  in  the  forest,  and  others  on  the  grass  land.  Robber 
flies  seems  a  poor  name  for  these  powerful,  hairy,  pre- 
daceous  flies,  with  long  narrow  bodies  and  strong  legs. 
Hawk  flies  would  be  a  better  name,  seeing  how  they 
pounce  upon  their  prey  ;  in  some  six  years  of  work  in 
the  field  I  can  only  once  remember  seeing  an  Asilid 
pounce  on  its  prey  sitting. 

Emphasis  has  already  been  laid  upon  the  importance 
to  the  theory  of  mimicry  of  noting  the  prey  of  Asilidae. 
It  is,  I  think,  quite  certain  that  the  fly  injects  poison 
into  the  victim  the  moment  it  has  been  captured  and 
the  proboscis  has  been  plunged  into  it.  The  prey  seems 
to  succumb  at  once  before  it  can  have  been  sucked  dry, 
and  if  one  actually  witnesses  the  capture  and  at  once 
catches  both  insects  the  prey  is  almost  always  found 
to  be  dead,  or  feebly  moving  its  legs  only.  Only  once 
have  I  met  with  an  exception  to  this.  An  Asilid  was 
seen  to  catch  a  bug,  and  I  struck  at  it  with  the  net.  The 
fly  escaped,  but  dropped  the  bug,  which  was  found  to  be 
apparently  unharmed. 

Another  family  of  Diptera,  Chironomidae  or  "  gnats,"  is 
worth  mentioning  here,  owing  to  the  abundance  in  which 
they  appear  over  the  lake  during  and  shortly  before  the 
rainy  season,  resembling  clouds  of  smoke  from  distant 
steamers.  I  have  seen,  on  a  calm  day,  a  large  area  of 
water  covered  by  the  pupal  skins  of  these  flies,  the  pupae 
having  come  up  irom  quite  deep  water,  and  the  flies 
rising  in  a  cloud  from  the  surface,  which  was  of  a  brown 
tint  from  the  myriads  of  empty  skins.  When  these  flies, 
called  "E'sami"  by  the  natives,  and  looking  more  or  less 
like  mosquitoes  without  the  sucking  proboscis,  have 
drifted  in  a  cloud  on  to  some  land  they  find  shelter  from 
the  wind  on  the  lee  side  of  trees  and  bushes,  where  they 
may  be  seen  hovering  in  a  cluster,  the  end  of  which, 
furthest  from  the  tree,  is  strung  out  and  torn  by  the  wind. 


318  SUNDRY  INSECTS 

On  a  very  calm  and  damp  clouded  day  the  air  is  filled 
with  the  high  piping  of  the  Sami,  hovering  in  myriads 
in  the  shelter  of  bushes,  and  a  sudden  noise  will  cause 
them  all  to  rise  suddenly  upwards.  It  was  very  amusing 
to  sing  a  scale,  for  one  note  appeared  especially  to  upset 
the  Sami,  and  when  it  was  reached  every  member  of 
the  hovering  cloud  would  simultaneously  leap  an  inch  or 
so  upwards.  The  natives  catch  large  numbers  in  baskets 
like  strawberry  baskets  made  of  plaited  grass  through 
which  a  stick  is  passed  ;  the  whole  is  vigorously  waved 
about  in  a  cloud  of  Sami,  the  basket  rotating  around  the 
stick,  which  passes  across  its  diameter.  The  catch  is 
compressed  into  a  cake,  but  I  do  not  know  how  it  is 
prepared  for  food. 

Sami  have  an  odour  of  the  lake  which  it  is  difficult 
to  describe — a  smell  like  weeds  and  fish  from  a  muddy 
pool  ;  it  is  a  common  saying  at  Entebbe  that  the  arrival 
of  clouds  of  these  gnats  produces  an  outbreak  of  nasal 
catarrh  among  the  white  inhabitants  ;  possibly  this  is 
of  the  nature  of  "  hay  fever." 

Spiders. 

The  most  noticeable  fact  about  spiders  on  the  islands 
has  been  already  recorded  in  the  account  of  the  tour 
in  1914,  namely,  the  extraordinary  abundance  on  certain 
islands  of  the  huge  Nephila,  and  the  sheets  of  their  webs. 
It  was  noteworthy  that  on  some  of  the  islands  the  spider 
was  present  in  normal  numbers  only,  as  on  Kibibi.  Spiders, 
generally,  are  called  "  Nabubi  "  by  the  Baganda.  A 
curious  habit  has  been  noticed  in  the  case  of  a  species, 
making  the  typical  "  orb  web."  Over  part  of  the  web 
it  would  spin  a  piece  of  very  conspicuous,  opaque,  glisten- 
ing white  silk,  which  was  visible  from  some  distance 
away.  The  design  in  the  same  web  would  be  changed 
from   time   to   time,   for  sometimes    there   would  be    an 


SPIDERS  319 

opaque  bar  right  across  the  diameter  of  the  web,  or  at 
others  a  zig-zag  between  two  of  the  radii  only.  The 
reason  for  this  is  obscure  ;  I  can  only  suggest  that  it 
is  analogous  to  the  trapper's  artifice  of  putting  an  object 
across  the  track  of  some  animal  which,  making  a  detour 
to  avoid  what  it  imagines  to  be  a  trap,  falls  into  the  real 
trap  set  at' the  side.  An  insect  on  the  wing,  supposedly, 
sees  the  conspicuous  part  of  the  web,  takes  care  to  fly 
past  the  side  of  it,  and  is  caught  in  the  inconspicuous 
part  which  it  has  not  seen. 

On  an  earlier  page  attention  was  directed  to  silver 
markings  on  insects  ;  a  spider  found  on  Dwaji  Isle  in 
1919  was  notable.  It  was  of  fair  size  and  spun  its  web 
among  heads  of  dry  grass  ;  the  colour  of  the  cephalo -thorax 
and  front  part  of  the  abdomen  was  pure  silver,  the  rest 
of  the  abdomen  was  dark,  but  speckled  with  yellow  and 
with  a  series  of  silver  bands  ;  the  legs  were  banded  alter- 
nately dark  and  speckled-yellow. 

Of  the  smaller  members  of  Arachnida,  Ticks  call  for 
notice,  but  only  on  account  of  their  great  scarcity  on 
the  islands.  This  is  presumably  associated  with  the 
absence  of  cattle  and  all  buck  except  the  Situtunga  ; 
and  if  the  islands  could  be  again  inhabited  it  should  be 
possible  to  keep  cattle  there  free  from  ticks  and  therefore 
from  the  diseases  carried  by  them. 

The  Varanus  often  has  numbers  of  ticks  on  it,  but 
these  are  not  of  the  species  which  feed  on  cattle  ; 
prettily  decorated  ticks  ^  have  also  been  found  on  the 
Horned  Puff  Adder.  The  islands  are  also  singularly 
blest  in  the  absence  of  Scorpions,  which  were  not  met 
with  ;  possibly  the  climate  is  too  continuously  humid 
for  them. 

The  great  group  of  Myriapoda  calls  for  passing 
notice,  firstly  because  of  the  absence  of  the  huge 
centipedes  found  in  some  parts  of  Africa,  and  secondly 

^  Aponomma  Iceve. 


820  SUNDRY  INSECTS 

on  account  of  the  great  abundance  of  giant  Millipedes 
("  E'gongolo ").  These  fine  creatures,  with  cylindrical 
bodies  some  six  to  eight  inches  long,  as  thick  as  one's 
finger,  clothed  in  rings  of  polished  black  armour  with 
reddish  legs,  are  really  extremely  handsome.  They  may 
often  be  seen  on  the  sandy  beach  feeding  on  decaying 
rubbish  cast  up  by  the  waves,  and  are  especially  notice- 
able when  rain  is  coming.  They  were  not  met  with  on 
certain  of  the  smaller  islets,  which  were  yet  of  suflBcient 
size  to  be  expected  to  support  them. 

I  think  that  they  are  occasionally  devoured  by  the 
Enswa-swa,  for  rings  of  their  armour  may  be  seen  in  dried 
excrement  believed  to  be  of  that  reptile.  But  I  am 
quite  unaware  what  are  the  main  checks  on  the  increase 
of  these  millipedes  ;  possibly  the  greatest  loss  is  caused 
by  enemies  that  devour  the  eggs,  or  parasites  of  the  eggs. 
It  is  a  curious  fact  that  I  cannot  remember  having  seen 
a  specimen  less  than  half  grown. 

Crustacea. 

Small  crabs  are  one  of  the  factors  of  the  lacustrine 
fauna  which  suggest  the  sea,  and  they  are  abundant  in 
shallow  water.  Superficially  they  much  resemble  crabs 
of  a  couple  of  inches  in  diameter  that  one  finds  in 
seaside  pools.  The  natives  call  them  "  Enjaba.^'  One 
was  found  under  a  stone  among  damp  debris  about 
twenty  yards  away  from  the  water,  a  young  and  lively 
specimen. 

Crayfish  were  never  met  with,  but  shrimps,  looking 
much  like  the  common  marine  species,  abounded  in 
shallow  weed  grown  waters. 

The  natives  call  them  "  Obuduli,"  and  use  them  as 
bait  for  fish,  but  I  do  not  think  they  eat  them. 

Fish  lice,  of  two  species,  were  met  with  on  the  "  Mamba  " 
and  "  Mal§  "  fish  already  described,  and  specimens  sent 


i 


MOLLUSCS  321 

to  the  British  Museum  proved  to  be  of  some  value  and 
interest.! 

Woodlice,  like  other  creatures  such  as  earwigs,  scor- 
pions and  centipedes,  usually  regarded  as  objectionable, 
were  exceptionally  scarce  on  the  islands,  and  this  was 
very  surprising,  for  one  would  have  expected  a  com- 
paratively equable,  damp  climate  to  afford  favourable 
conditions. 

Molluscs. 

The  lake  shore  abounded  with  univalves  and  bivalves 
which  had  quite  a  marine  appearance  ;  securely  fastened 
to  rocks  was  a  species  resembling  the  common  oyster. 
Besides  these  were  others  very  closely  resembling  our 
English  genera  of  fresh-water  snails  and  mussels. 

A  curious  slug,  that  had  very  short  tentacles 
and  seemed  to  have  no  "  mantle  "  at  all,  was  found 
slowly  crawling  on  wet  sand,  where  also  the  large  Ampul- 
laria  were  occasionally  thrown  up  by  waves.  Shells  of 
these  large  molluscs  may  be  found  on  the  lake  shore, 
apparently  battered  to  pieces  on  a  stone  as  our  garden 
snails  are  by  thrushes.  I  strongly  suspect  this  to  be 
the  work  of  the  "  open-bill  "  stork. 

On  Damba  Island  there  was  found  quite  commonly  a 
snail  of  the  type  of  our  English  Vitrina,  but  very  much 
larger,  with  a  thin  fragile  shell  practically  enveloped  by 
extensions  from  the  mantle.  This  was  easily  procured  in 
numbers  when  the  "  Ensanafu  "  ant  had  been  hunting,  for 
its  only  means  of  escape  was  to  crawl  upwards.  Should 
it  happen  to  come  to  the  top  of  a  stem  it  was  unable  to 
descend  again  and  face  the  ants,  so  defended  itself  by  emit- 
ting bubbles  to  form  a  mass  of  foani  completely  surround- 
ing itself,  which  the  ants  could  not  penetrate,  and  if  they 
bit  into  it  they  could  reach  nothing  solid.  These  white 
masses    of    foam,    like    "  Cuckoo    spit,"    were    very    con- 

^  Dolops  ranarum   and   Argulus  ajricanus. 
22 


322  SUNDRY  INSECTS 

spicuous  in  the  forest  after  a  raid  by  the  Ensanafu.  Speci- 
mens sent  to  England  were  found  by  Lieutenant-Colonel 
Godwin- Austen,  F.R.S.,  to  be  a  species  hitherto  un- 
described.  On  Tavu  Island,  among  dead  leaves,  I  once 
found  a  minute  snail  like  a  Vertigo,  but  lost  it  again. 

A  very  large  snail  {Achatina)  with  pointed  shell  of 
brown  colour,  the  mouth  tinted  with  purple,  was  common 
on  Damba,  and  I  once  disturbed  an  Enswa-swa  which 
had  apparently  been  much  interested  in  one  that  was 
laying  its  eggs  in  the  ground.  It  is  possible  that  the 
eggs  were  the  attraction  and  not  the  snail  ;  they  were 
a  little  larger  than  a  pea,  but  not  spherical,  with  a  firm 
shell  of  canary-yellow  colour. 

The  general  name  for  a  snail  in  Luganda  seems  to 
be  "  E'sonko:' 


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INDEX 


Abdimia  abdimii,  155 

Achatina,  97,  822 

Acraea,  prey  of  Belongaster,  285 

alciope,  variations  in,  235,  240,  241 

egina,  103,  120,  205 
as  model,  233,  238 

encedon,  109,  110,  112,  120 

jodutta,  as  mimic,  233 

nataliea,  courtsliip  of,  224 
pseudegina,  120 

pentapolis,  104 

perentia,  205 
as  mimic,  233 
larvae  of,  prey  of  bug,  219 

terpsichore  and  Syntomid  moth,  222 

zetes,  116,  120,  205 
parasites  of,  220 
as  model,  233 
Acraeinae   (see    also    Acraea,   Planema), 
103-5,   109,   110,   112-5,    120,   125, 
205 

emit  distasteful  fluid,  210 

toughness  of,  225,  213 

courtship  of,  224 

nuptial  flight  of,  225 

as  models  and  mimics,  233,  242 
Acrididae,  136,  314 

aposematic,  209-12,  215 
ActophUus  africanus,  153 
/Sna,  159 
Agamidae,  185 

("  Akalerwe  ")  (see  Hydrochelidon),  146 
("  Akamunyi  ")  (see  Milvus),  161 
("  Akasalu  ")  (see  Galactochrysea),  150 
"  Akasonzi,"  141,  194 
("  Akatassa  ")  (see  Lily  Trotter),  153 
("  Akawundo  ")  (see  Bat),  143 
Albert,  Lake,  68 
(Akkornea)  (see  "  Oluzibaziba  "),  70 
Aletis  erici,  larvae  of,  214 

evidence  of  insularity,  103,  106 
Aloe,  evidence  of  insularity,  116 
("  Amajansi  ")  (see  Cyrtacaiitfiacris),  314 
Amauris,  as  models,   242,   268,   273 

Mendelian  relationship  in,  268-9 
Amauris  echeria,  114 

evidence  of  relative  inedibility  of,  238 

niavius,  103,  114,  222 

psyttalea,  114 
courtship  of,  222 
Ambatch,  70,  9ft-8,  108,  111,  117, 121, 122, 
147,  158,  176,  194,  303 

flowers,  165,  303 
Ammophila,  298-300 
Amoeba,  11 

Amphidesmus  analis,  307 
Ampullaria,  154,  184,  321 
Anal  tufts  of  Amauris,  in  courtship,  222 
Anastomus  lamelligerus,  97,  109,  146,  164 

323 


Andronymus  leander,  110 
Anhinga  rufa,  148 

Ant  (see  alsoDorylus,  Megaponera,  '  Obusa- 
jisaji,"  (Ecophylla,  Paltotkyreus),  97, 
108,  207,  276-84 

enemies  of,  172,  185,  282 
(Antelope),  and  Trypanosomes  (see  Bush- 
buck,  Keedbuck,  Situtunga,  Water- 
buck) 
Anthia  absent  from  islands,  307 
Ant  lion,  and  Glossina,  52 
"  Anyamberege,"  70,  116 
Aphnaeus  orcas,  124,  199 
Apodidae,  larvae  of,  213,  220 
Aponomma  laeve,  319 

Aposeme  (see  also  Colouration,  aposematic), 
206 

implies  unpleasant  not  necessarily  dis- 
tasteful quaUty,  207,  213 

must  be  simple,  206,  235 

combined  with  procrypsis,  206-7 

displayed  when  necessary,  206,  210-2 

proved  to  be  of  value,  212 

of  larva,  used  by  pupa,  216-7 

Lycid,  231-2 

of     Planema-Pseudacraea     association, 
246-9,  251-3 
Arachnidu,  318-9 

mimetic,  227,  233 
Arctiidae,  aposematic,  210-1 

hairy  larvae  of,  213 
Ardea  melanocephala,  158 

purpurea,  156 
Argulus  africanus,  321 
Arum,  110 
Asilidae,  316-7 

and  Mantidae,  120,  124 

prey  of,  54,  97,  317 

poison  injected  by,  317 
Aslauga  purpurascens,  106 
Aspidomorpka,  insular  abundance  of,  120-1 
Atella,  238 
Aterica  galene,  102 
Atractocerus  brevicornis,  309 
Attitude  of  caterpillars,  200-1,  214 

terrifying,  221 

importance    of,   for    procrypsis,    196-8 
216 
for  mimicry,  227,  311 
Atjsten,  E.  E.,  on  name  "  Tse-tse,"  19 

Bacilli  and  Trypanosomes  in  Glossina,  40, 

41 
Bagshawe,  Dr.  A.  G.,  54 
Baker,  Dr.,  23 
Balceniceps  rex,  155 
Balance  of  nature,  102,  105,  110,  120,  124, 

171,  176.  213-20,  316 
Balantidium,  11 


324 


INDEX 


BdUarica  regulorum,  152 

booming  noise  of,  77 
("  Balwa  ")  (see  Ardea  purpurea),  156 
Banda  Isle,  89 
Barbatula  leucolaima,  167 

Barbel,  194  .,,,„, 

Barbet,  scarce  on  islands,  167 

B\TES,  H.  W.,  195,  205,  225,  229-30,  235, 
281 

Bats,  98,  112,143-4 

Bees,  117,  121,303-4 

prey  of  Bee-eaters,  1<  2,  23o 

not  intrinsically  cUstasteful,  207 

Carpenter,  (see  Xylocopidae),  108 

Rpe-eater    97,   102,  115,  120,  171-3 
food  of,'  172,  173,'  218,'235,  237   282,  285 
Drongos     &     Rollers,     interchangeable 
function  with,  171,  176 

Beetle,  305-9  ^  .  ,  .^  -.oi  199 
as  evidence  of  insularity,  121,  122 
distasteful  to  monkey  eaten  by  Boiler, 

218,  306 
mimetic,  231-2,  308-9 
wood-boring,  309 
BELCHER,  C.  F.,  145,  162,  177 
Belenois,  120 

attacked  by  bu-ds,  237-8 
courtship  of,  223 
seasonal  forms  of,  202 
Belong  aster,  284-6 
prey  of,  97,  108,  285 
eaten  by  Bee-eater,  172,  285 
as  model,  285,  310,  311 
enemies  of,  286 
compared  with  Fossors,  287 
Bembex,  95,  286,  288-93 
and  Glossina,  53,  288-93 
enemies  of,  291-293 
capensis,  292-3 
forcipata,  288-92 

ugandensis,  293  .        j.      mo 

Bird-droppings  resembled  by  insects,  198, 

199,  204,  216 
Birds  and  fflossiua,  37,  53  . 

of  islands,  compared  with  mainland,  145, 

164,  166-7,  171,  173,  17a-7,  1<9 

local  races  on  islands,  275       ^    ,,  ,„„ 

iniectivorous,  on  "  Spider  islands,    102, 

105,  120,  124 

attacks  of,  on  butterflies,  111,  173, 

208,  225,  235-8.  267-8 
attacks  of,  on  butterflies,  selective,  238 
species  of,  interchangeable  function  of, 
171,  176 
Bitis  arietans,  188 

nasicornis,-Q6,  187-8 
Bittacus,  310 
Blattidae,  314 

hunted  by  Dorylus,  2^9-80 
(Blind  worm)  (see  Slow  Worm) 
Boomslang,  191 
(Bottle-bird)  (see  Coucal) 
Bracken,  116 
Braconidae,  220 

as  models,  233,  307,  308-9 
Lycoid,  232  ^ 

BRUCE,  SIR  David,  7,  14,  22,  24,  26,  54 

BUBEMBE   ISLE,  89,  92 
Bubo  lacteus,  163       _  „r    r , 

Buffalo  and  0.  morsitans,  35,  54 
(Buffalo-gnat)  (see  Simuliidae) 
Buff  tip  moth,  198 

i^^iLLAK,'l9.  114.  145,  149   166,  180, 
215,  219,  221-2,  283,  308-9 
local  races  on,  139,  174,  176.  275 
Breeding  places  of  Olossma  on.  57 
Pgeudacraea  eurytug  on,  268-9 


(Bug)  (see  Eemiptera) 
BUGUYE  Isle,  90 
BuLAGO  Isle,  94-5,  182-4 

Glossina  on,  47 

Breeding  place  of  Olossina  on,  69 

butterflies  on,  125 
Bul-bul,  105,  117 
Bunaea  phaedusa,  201 
BUNYAMA  Isle,  89,  93,  143 
(Burnet  moth)  (see  Zygaenidae) 
Bushbuck  and  T.  gambiense,  27 

compared  with  Situtunga,  133 
BusiRi  Isle,  183 

(Bustard)  (see  Otis)  ^ 

Butterflies,  attacked  by  bnds.   111,   173. 
208,  225,  235-8,  267-8 

courtship  of,  221-5  ,     ,  ^r 

numbers  on  different  islands,  125 

mimetic,  less  shy  in  absence  of  insectiv- 
orous birds,  102 
BuvuMA  Isle,  size  of,  67 

mortality  from  Sleeping  Sickness  on,  7-» 
("  Buvumira  ")  (see  Xylocopidae),  303 
Buzzard  and  Chamteleon,  163 
BwiGGi  Isle,  93 
Byblia,  119 

courtship  of,  223-4 
Bycanistes  suboiUniricus,  168 

an  aposematic  bird.  302 

cry  of.  77,  81 

Caeergates  leucosticta,  310 

preys  on  Olossina,  53,  54 
Camoephaga  nigra,   attacking   ButterHies, 

237 
Cane,  70.  96,  98,  110,  111,   118 
Canoe,  description  of,  and  names  of  parts, 

84-7 
Caprimulgus,  cry  of.  81,  173 
{Capsidae,  mimetic)  (see  Eolopeltis,  Xene- 

tomorpha) 
(Carabidae)  (see  Anthia)  . 

Carpenter,  Dr.  G.  D.  H.,  on  inheritance 

of  small  variations,  241 
(Cassididae)  (see  AspidomorpM) 
Castalius  isis,  119 
Castellani,  Dr. -A..  23 
Caternillar  199 
insular  abundance  of,  100,  101,  103,  104, 

106,  116 
enemies  pf,  101,  172,  220,  288,  316 
instincts  of,  200  , ,  ,  , 

procryptic,      resembbng     bird-dropping, 

199-  216  ,.      ^  ,,    „,. 

rarely  becomes  aposematic  adult,  tin 
with  special  defence,  206 
aposematic,  becomes    aposematic    adult, 
214,  239  ^.       ,   ,. 

if  hairy,  may  become  procryptic  adult, 
213 
hairy,  irritant  hairs  of,  213-4 

enemies  of,  166,  218,  294,  316 
very  large,  but  concealed,  201 
Catopsilia,  120 

Caves,  98,  108  .     ^,      ■       r-r 

not  good  breeding  places  for  Gtlossma,  57 

Centipede,  large,  absent  from  islands,  319, 

321 
Centropidae,  102,  110,  116,  120,  165-6 

(food  of,  see  Ceuthmochares) 
Cerambycidae,  121,  307-9 

mimetic,  232,  233,  239,  307-9 
(Cercopithecus)  (see  Monkey) 
Ceroplesis  signata,  121 
Ceryle  maxima,  169 

rudis,  169 
Cetoniidae,  121,  232 
Ceuthmochares  oeneus,  166 


INDEX 


325 


Chagas,  Dr.,  14 
Chakididae,  51,  52,  220,  313 
Chanipeleon  and  buzzard,  163 
Charaxes,  97,  103,  106,  11-1 
directive  markings,  208 
etheodes,  transitional  forms,  241 
Chenalopex  wgyptiacus,  81,  96,  146,  149 
nest  of,  150 
and  mongoose,  142 
Chironomidae,  79,  317-8 
food  of  CEcophylla,  283 
Chrysididae,  prey  of  Bee-eater,  172 
Chrysococcyx,  167 
Chrysomelidae,  insular  abundance  of,  122 

Lycoid,  232 
ChrysophyUum,  98,  215,  259,  263 
Chrysops  brucei,  315 
enemies  of,  97,  293 
Chrysopsyche  varia,  cocoon  of,  217 

caterpillars  of,  200,  216 
Cicada,   insular   abimdance   of,    118 
Cicindelidae,  307 
Ciconia  nigra,  155 
Cilix  glaucata,  198 
Cirphis,  196 
Clegg,  18,  20 

Climate  of  islands  and  mainland  compared, 
44,  72 
storms,  73-5 

effect  upon  G.  palpatio,  42-6 
Clouds,  75,  101 
Coccidae,  116 

(Cockroach)  (see  Blatiidae) 
Coeliaxis  carinata,  304 
Coincidence,  and  detailed  mimicry,  234-5, 

310 
Colias,  nuptial  flight  of,  224 
CoUidae,  absent  from  islands,  167 
Colouration,  classified,  195 
held  to  be  always  concealing,  204,  238 
and  habit  associated  variables,  239 
anticryptic,  203-4 
apatetic,  195,  234 

aposematic   (see   also    Aposeme),  204-6, 
209-16 
and  noisy  flight,  168 
versus  Thayerism,  204-5 
and  bold  demeanour,  209-12 
proof  of  value  of,  210-2 
and  resistance  to  injury,  212-3,  226 
effect  increased  by  massing,  215 
carried  through  all  stages,  214 
cryptic,  195 
epigamic,  195 
procryptio,  196^202,  312 

combined  with  special  aposeme,  206-7 
general,  196,  199 
special,  196,  197-9,  216 

analogous  to  mimicry,  234 
effect  increased  by  massing,  216 
pseudaposematic,  229 
pseudosematic,  195 
synaposematic,  230-1 
Concealment   of   all   creatirres,    theory   of 
(see  Longley,  Thayer) 
by  breaking  up  large  area,  200-1 
(Copper-smith)  (see  Barbatula) 
Copridae,  305-6 

eaten  by  Roller,  218 
Conorhinus,  18 
Cook,  Dr.  A.,  7 

Cormorant,  96,  97,  117,  121,  122,  146-8 
nesting  places,  147,  158 
robbed  by  gull,  146 
Cossypha,  178-9 
(Coucal)  (see  Centropidae) 
Courtship  of  butterflies,  221-5 
(Crane,  crowned)  (see  Balearica) 


Crayfish,  not  met  with  in  lake,  320 
Creepers,  72 

make  shelter  for  Glossina  pupae,  58,  64 
Crickets,  80 
Crithidia,  12 
Crocisa  meripes,  303-4 
Crocodile,  180-2      ■ 

abundance  on  different  islands,  94,  96, 
99,  104,  111-3,  115,  118-9,  122, 
124 

relations  with  Varanus,  183-5 

as  food  for  O.  palpalis,  38,  39,  181 

Trypanosome  of,  40 

basking  place  of,  180 

nest  of,  90,  98,  115,  122,  181,  182 
Crotalaria  striata,  108 
Crow,  114 
Crustacean,  320-1 

Ostracod,  found  in  gut  of  Glossina,  42 
Cuckoo,  102, 166,  167 

feeds  on  hairy  caterpillars,  218 

(bronze)  (see  Chrysococcyx) 
(Cuckoo  shrike)  (see  Campephaga) 
Cuculus  solitarius,  166,  167 
CuMjiiNG,  Gordon,  20 
Cycle,  in  life  history  of  Protozoa,  17,  25,  26 
Cynthia  cardui,  106 
Cyrtacanthacris,  105,  170,  314 

Bamarius  splendidulus ,  219 
Damba  Isle,  8,  68,  114,  119 

notes  on  fauna  of,  131,  142-3,  145-6, 
158,  165,  176,  188,  197,  200,  227 
279,  280,  283,  315 

Glossina  on,  51,  58 

Ps.  eurytus  on,  256-9 
Danaida  chrysippus,  114,  120 

crossing  water,  100 

as  model,  242-3 

flight  of,  243 
Danaida  plerippus,  flight  of,  243 
Danainae   (see   also   Amauris,    Danaida) 
103,  114,  120,  125 

as  models,  106,  233,  242 

and  birds,  225,  235,  238 

toughness  of,  213 
Daniels  and  Newham,  ou  acute  Trypano- 
somiasis, 10 
Darter,  96,  97,  146,  14Y,  148,  158 
Darwin,  18,  224,  225 
Darwinism,  and  the  Mutation  theory,  195, 

198,  241,  262,  268-9,  270-2 
Depopulation  of  islands,  a  measure  against 
Sleeping  Sickness,  7,  8,  28 

eft'ect  on  fauna  and  flora,  29,  71,  139,  184 
Dermaptera,  314-5,  321 
Dicruriiae,  237  , 

absent  from  islands,  176 
Dictyophora  laticincta,  209-10 
Diloba  caeruleoccphala,  caterpillar  of,  239 
Diploptera,  286 

Diptera  (see  also  Chironomidae,  Glossina, 
Simuliidae,  Tahanidae),  315-8 

parasitic    (see    also     Jdia,     Stylogaster, 
Tachinidae),  294,  302 
Dirphya,  233,  308-9 

Disease,  a  disturbance  of  equilibrium,  16 
Distasteful  species,  reqiiire  to  advertise,  206 
DiXEY,  Dr.  F.  a.,  on  chance  resemblances, 
234 

on  Mullerian  mimics  of  second  degree,  248 
Dolops  ranarum,  321 
Domestic  animals  and  Trypanosoraes,  16 
Dorylus,  97,  186,  276-81 

male  comes  to  light,  80 
Dourine,  14,  18 
Dove,  159 
Dragon  fly,  309-10 


326 


INDEX 


Dragon  fiy,  prey  of  Bee-eater,  172 

bionomic  relations  with  Glossina,  53-4, 
310 
(Dronco)  (see  Dicruridae) 
Duck,  149 

Duke,  Dr.  H.  L.,  15,  27,  41,  185 
DUTTON,  Dr  ,  6,  23 
DwAji  Isle,  319 
DWANGA  Mkuutj  Isle,  104-5 

butterflies  on,  125 
DWANGA  Mto  Isle,  105-6 

butterflies  on,  125 
DwASENDWE  Isle,  106-7 

butterflies  on,  125 
Dyavodemu  Isle,  119-121 

butterflies  on,  125 
Dysentery,  11 
njjtisndae,  307 

Eagle  (Bateleur)  (see  Tfc^otarsus) 

(Crested)  (see  Snizaetus) 

Fish  (see  also  Haliaetiis),  160-1 
(Earwig)  (see  Fermaptera) 
East  Africa,   British,   Ps.  eurytus  in, 
245-6,   249,   252-4,   263 

Ex-German,   149,    152,    155,   173,   176, 
238,  282,  302-3,  303 

Portuguese,  9,  283 
Eciton,  281 

("  Egongolo  ")  (see  Millipede),  320 
("  E'gonya  ")  (see  Crocodile),  180 
(Egret)  (see  Egretta) 

Egretta,  81,  96,  97,  117,  120,  124,  146,  158 
("  E'jansi  ")  (see  Cyrlacanthacris),  105 
"  Ekinsambwe,"  70,  117,  122 
("  Ekinyira  ")  (see  Flying  Fox) 
("  Ekirikiti  ")  (see  Erythrina) 
("  Ekisagazi ")  (see  Elephant  grass)] 
("  Ekisinja  ")  (see  Barbel) 
"  E'konkomi,"  185 
Elanus  cceruleus,  162 
Elephant  grass,  105,  117 
Elgon,  Mt.,  Ps.  eurytus  on,  250 
Elminia  longicauda,  175 
Eltringham,  Dr.  H.,  222,  242,  244 
("  E'male  ")  (see  Mud-fish),  79,  193 
"  E'mamba  ")  see  Lung-iish),  193 
("  Embata  ")  (see  Goose),  149 
"  Embegede,"  194 

("  Empavana  ")  see  Ibis,  hagedash),  153 
("  Empungu  ")  (see  Eagle,  Ush),  160 
("  Empunya  ")  (see  Plover),  152 
("  Endegeya  ")  (see  Weaver  bird),  176 
("  Enfuflu  ")  (see  Tortoise),  186 
"  Engabi,"  138,  183 
("  Engadala  ")  (see  Cormorant),  147 
("  Engali  ")  (see  Crowned  Crane),  153 
("  Enga-nga  ")  (see  Horntaill),  168 
("  Enjaba  ")  (see  Crab),  320 
("  Enjobe  ")  (sec  Situtunga),  137 
("  Enkazalugya  ")  (see  Passer),  177 
"  Enkeie,"  194 

("  Enkobyokobyo  ")  (see  Gull),  146 
("  Enkolokoto  ")  (see  Megaponcra),  282 
('■  Enkonaiuasonko ")    (see    Stork,    open- 
billed),  154 
Enkusa  Isle,  108 
("  Ensanafu  ")  (sec  Doryhis),  276 
"  Ensenene,"  312 
"  Ensoga,"  104 

("  Ensogwe  ")  (see  Cormorant),  147 
("  Enswa-swa  ")  (see  Varanus),  182 
Entamoeba,  11 

Entebbe,   birds   at,   164,   167,    171,    175, 
177,  179 

Ps.  eurytus  at,  250-1,  258-9,  262,  266 
("  E'numba  ")  (see  Belonogaster),  284 
("  E'uunda  ")  (sec  Stork),  155 


("  Envubu  ")  (see  Hippopotamus),  126 
Enyaliopsis,  211 

emits  Irritant  fluid,  313 
("  Enyange  ")  (see  Egretta),  158 
("  Enyonza  ")  (see  Cossypha),  178 
Ephemeridae,  79,  80 
Ephippigeridae,  313 
Ephippiorhynchus  senegalensis,  155 
Epigamic  colouration,  195 
Epinephele  janira ,  nuptial  flight  of,  224 
Epitoxis  albicimta  and  Acraea,  222-3 
Erlangea  tomentosa,  107,  113,  117 

attractive  to  butterflies,  205 
("  Eryato  ")  (see  Canoe),  84 
Erythrina  tomentosa,  110,  112,  205 
("  E'salambwa  ")  (see  Bitis),  188 
(    E'sami  ")  (see  Chironomidae),  317 
"  E'sonko,"  322 
("  E'timba  ")  (sec  Python),  188 
•'  E'tungulu,"  71,  96,  118 
Eucoma  atricosta,  evidence  of  insularity,  116 
Euphorbiaceae  and  Protozoa,  13 
Eupterotidae,  caterpillars  of,  200,  316 

evidence  of  insularity,  l()3-4 
Euralia,  97,  102,  104,  114,  124 

dinarcha,  103 

dubia,  103,  105,  106 
Mendelian  relationship  in,  268-9,  272 

Factor,  Mendelian,  270,  272 

Fantham  and  Porter,  on  Herpetomotuis,  16 

Ferns,  104-7,  115-7 

Fig  trees,  71,  113,  115,  117,  159 

Finches  (see  Friiigillidae) 

Bishop  and  Widow,  absent  from  islands, 
176-7 
Fireflies,  309 
Fire,  spontaneous,  76-7 
Fish  (see  also  E'male,  E'mamba),  193-4 

as  weather  prophets,  78-9 
Fish  lice,  320-1 
FiSKE,  W.  F.,  51,  71,  101,  108,  110,  115 

121,  123,  124,  127,  140 
Flagella,  11 

Flagellates,  relation  with  insects,  16 
Flamingoes,  absent  from  Lake,  156 
Fliglit,  aposematic,  168,  301-2 

of  model  and  mimic,  ^43,  252,  308 
Flowers,  70-2 
Fluid,  emitted  by  distasteful  insects,  210, 

211,  231,  313 
Fly  beach,  69 

Flycatcher  (see  also  TcMtrea),  96,  97,  102, 
104,  109,  112,  120,  173-5 

niglitingale-like,   107-8,    113,    115,   117, 
121-3 
Flying  fox,  143-4 
FORDE,  Dr.,  23 
Forest,  abrupt  edge  of,  71 
Formicidae,  233 
Fossor,  53,  95,  286-303 

enemies  of  (see  also  Idia),  302 

different  stages  in  methods,  286-7 

Lycoid,  232,  293 
FoUNTAlNE,  Miss,  on  Pseudacraea  eurytus, 

259 
Fowls,  and  aposematic  grasshopper,  212 
Francolin,  forest,  159,  160 

call  of,  81 
Fraser,  a.  D.,  54 
Friiigillidae,  177 
Frogs,  noises  of,  80 

as  weather  prophets,  78 

Tree,  190 

and  snakes,  190-3 
Fryer,  J.  C.  F.,  269 
("  Fulungu  ")  (see  Musophaga),  165 
FUMVB  Isle,  89,  92 


INDEX 


327 


Gaboon,  Pseudacraea  eurylus  from,  248 
Galactochrysea  emini,  146,  160 
(Gamboge  tree)  (see  Haronga) 
Game,    Glossina   and   Trvpanosomes  (see 

also  Situtunsa),  15,  25,  26,  35 
Game  birds,  scarce  on  islands,  159-60 
Gamia  biwholzi,  106,  110 
Gecko,  absent  from  islands,  186 
Genet,  142 

Geographical  distribution,  of  models  and 
niimics,  235,  241,  247,  250-1,  264, 
262 
Geometridae,  caterpillars  of,  214,  239 

moths,  199,  233 
GlossiiM  (see  also  Tse-Tse),  81 

geograpliical  distribution  of  genus,  19 
number  of  species,  19 
life  history,  22,  50,  54 
brevipalpis,  comes  to  light,  35 
morsitans,  early  accounts  of,  19-21 
and  buffalo,  35,  54 
breeding  places,  65 
enemies  of,  51 
and  Trypanosomes,  9,  23 
palpalis,  21 

distribution  of,  9,  24 
numbers  of,  30 

and  crocodiles,  48-9 
proportions  of  sexes,  31-2,  45,  47-8 
length  of  life,  42-4 
effects  of  climate  upon,  42-6 
dependant  upon  shade,  21,  32-4,  45 
does    not    cross    open    water    unless 

carried,  34,  48 
birth  of  larva  of,  50   ■ 
emergence  from  puparium,  22,  52 
time  and  method  of  feeding,  34-5,  45 
proved  to  carry  Sleeping  Sickness,  2 

4,  7 
no  inheritance  of  Trypanosomes,  25 
duration  of  infectivity  of  one  fly,  26 
infective  in  absence  of  mankind,  42 
breeding  places  of,  first  discovered,  54 
characteristics  of,  56-60 
ideal,  58,  63 
"  Loci,"  57 

searched  for  by  female,  56,  63 
destruction    of,  not   possible  by   only 
clearing  breeding  grounds,  60 
by  artificial  breeding  grounds,  62-5 
enemies,  of  larva,  49,  50 
of  pupa,  50-2 
of  fly,  52-4 
lood  of,  36-42 
mammalian,  36 
non-mammalian,  36-9 
vegetable,  41 
water,  42 

endurance  of  starvation,  42 
larvae  and  pupae  of,  requirements  of, 
55-60,  62 
resistance  to  adverse  conditions,  46-7 
numbers  on  different  islands,  96-8, 

100,   102-11,   113-8,   120-3 
numbers    of    pupae    on    different 
islands,  57,  58,  111,  119,  122 
tachinoides,    the    only    species    outside 
Africa,  19 
(Goatsucker)  (see  Nightiar) 
Gold  markings  on  insects,  199 
(Goose,  Egjptian)  (see  Chenalopex) 
(Pigmy)  (see  Nettopus) 
(Spur  wing)  (see  Plectropterus) 
Grasshopper,  as  evidence  of  insularity,  105, 
110 
aposematic,  209-12,  215 
Gregariousness,  increases  conspicuousness, 
215 


Gregariousness,  rare  in  procryptic  species, 

215-6 
Gull,  78,  81,  117, 145, 146 
Gyrindae,  307 

Haematopota,  97,  315 

Hairs,  of  caterpillars,  206,  213 

Halcyon  chelicuti,  171 

senegalensis  (see  also  Kingfisher),  170 
Haliaetus  vocifer,  160-1 

cry  of,  78 

and  prey,  193 

and  Goliath  heron,  156-7 
(Hammer  head)  (see  Scopm) 
Haronqa    madayascariensi-s,    attractive    to 

insects,  232,  237,  244,  307 
Heliconinae,  243 
Helotarsus  ecaudatus,  164 
Hemiptera  (see  also  Capsidae) 

carrier  of  disease,  18 

anticryptic,  204 

prey  of,  204,  219 

aposematic,  215 

mimetic,  228,  231,  309 

disliked  by  Dorylus,  280 
Heredity  of  small  variations,  271-2 

in  Papiho,  241,  269 
Herodias  alba,  146,  158 
Herons,  96,  107,  109,  122,  156-8 

Buff  backed,  146,  158,  159 

GoUath,  96,  99,  109,  117,  146,  156-8 
and  Fish-eagle,  156-7 

(Great  White)  (see  Herodias) 
Herpetomonas,  12,  13 

of  water  scorpion  pathogenic  to  mouse,  16 
Hesperidae  (see  also  Andronymus,  Gamia, 
RhopalocamjHa),  106,  112,  114,  118, 
120,  125 

prey  of  Bembex,  288 
Hippopotamus,  95,  110,  112,  118,126-31, 

grazing  ground,  98,  130 

noises  of,  80,  89,  127 

pathways,  118,  126,  128 

sleeping  places,  124,  126,  127 

wallows,  128 
(Hornbill)  (see  Bycanistes,  Lophoceros) 
Humidity,  on  islands  and  mainland,  44 

effects  upon  Glossina,  44,  46 
Hydrochelidon  leucoptera,  78,  146 
Hymenoptera,  prey  of  Bee-eaters,  172,  218, 
235,  282,  285 

not  always  intrinsically  distasteful,  207 

parasitic,  220,  313 

syn-aposematic,  231-2 

as  models,  233,  308-311 
Hypertely,  196-7 
Hypolimnas  misippus,  106 
Hypsidae,  214 

Ibis  aethiopica,  154 
hagedash,  97,  146, 153-4 

cry  of,  81,  130 
sacred,  96,  99,  146,  154 
Ichneumon  flies,  49,  51,  101,  287-8,  297 
Idia,  291-2 
Infusoria,  11 
Insects,  as  weather  prophets,  79-80 

parasitic,  49,  51,  52,  101,  219,  220,  297-8, 

288,  313,  316 
predaceous,  prey  of,  204,  219,  310 
protected,  217 

enemies  of,  218-220,  235,  285,  315 
immunity  only  relative,  217 
Instinct,  limitations  of,  200 

in  accordance  with  colouration,  196,  198, 
209,  216,  227,  228,  308 
Insularity,  faunal,  100-6,  109,  110,  116-9, 
120-2,  124,  174-5,  275 


328 


INDEX 


Insularity,  floral,  105,  107,  108,  110,  113, 

116-7 
Ipomaea,  64,  70,  107,  117,  121 
Irrisorinae,  absent  from  islands,  173 
ISENTWA  Isle,  111,  128,  l83 

butterflies  on,  125 
Islands,  68,  69,  72,  89,  90,  108,  114 

largest,  67 

of  Rome  and  Kerenge  groups  compared, 
108-9 

derivation  of  fauna  and  flora,  109,  119 

smallest  on  which  Glossina  breeds,  122 

with  monlveys,  131 

with  Situtunga,  101,  117,  139-40 

faunal  peculiarities  (see  also  Insularity), 
145,    159,    164-7,    171,   173-7,    179, 
237,  304,  319,  321 
Ispidina,  169 

of  evil  omen,  170 
Ithomiinae,  243 

Jennings,  Prof.,  272 

JINJA,  126,  161,  162,  164,  167,  171,  175, 

177,  184,  196,  218,  315 
Jordan,  Dr.  Karl,  on  Ps.  eurytus,  244-5, 

255 

Kagera,  R.,  67-8,  137 

barrier  to  Megaponera,  282 
Kakindu,  Ps.  eurytus  at,  274 
"  Kala-azar,"  13,  16 
Kallima,  221 

("  Kasimagizi  ")  (see  Kingfisher),  169 
Kawaga  Islet,  122 
Kerenge  Isle,  161,  170,  109-10,  314 

butterflies  on,  125 

Sceliphro7i  on,  297-8 
KiBiBi  Isle,  119,  179,  318 

leopard  on,  141 
"  Kibo,"  70,  105 

KiKUYU  Escarpment,  P.  dardanus  on,  271 
("  Kimbala  ")  (see  Heron,  Goliath),  156 
KIMMI  Isle,  97-9,  182-3,  188,  194,  201 

Glossina  on,  32,  47-9,  98 
breeding  places  for,  58,  60 

Ps.  eurytus  on,  273-5 

butterflies  on,  125 
Kingfisher,  110,  169-71 

cry  of,  78 
("  Kirimululu  ")  (see  Chrysococcyx),  167 
KiRUGu  Isle,  89 
Kisigalla  Isle,  92,  103 

butterflies  on,  125 
Kites,  96,  161-3 
Kiuwa  Isle,  68,  108,  111-2,  116,  179 

Olossina  on,  119 

butterflies  on,  113,  125 
Kizima  Isle,   95-6,   123,   154,   162,   175, 
179,  182 

butterflies  on,  125 
Kleine,  Dr.,  25 
KolopeUis  hergrothi,  309 
KOMB  Isle,  notes  on  fauna,  131,  140,  142, 
152,  275,  310 

Ps.  eurytus  on,  266-8,  274-5 
("  Kunguvu  ")  (see  Tchitrea) 
KuYE  Isle,  90 
KYAGWB  coast,  167,  176,  245,  251 

Lacertidae,  185 

Lachnocnema  bibulus,  109,  1 1 1 
Lamborn,  Dr.  W.  a.,  66,  273 
Lamiidae,  121,  233 
Laninrius  erytkrogaster,  175 
Laphyima   frugiperda,    evidence    of   insu- 
larity, 101 
Larus,  146 
Lasiocampidae,  199,  200,  206,  213,  216 


Lasioeampidae,  evidence  of  insularity,  103 

(Leaf  butterfly)  (see  Kallima) 

Leech,  18 

Leishmania,  13 

Leopard,  141 

Leptaletis  forbesi,  233 

(Leptomonas)  (see  Herpetomo)ms) 

Libythm,  115,  125 

(Lily  Trotter)  (see  Actophilus),  153 

Limenitis,  243 

(Limnotragus)  (see  Tragelaphus) 

Lipteninae,  107,  233 

Lithosiidae,  232 

Livingstone,  20,  21,  137 

Lizard  (see  also  Gecko),  108, 120-1, 185, 190 

fed  upon  by  G.  palpalis,  37 

prey  of  hawk,  163 
Locustidae  (see  also  Enyaliopsis),  312-4 

enemies  of,  163,  294-5 
(Longicorn)  (see  Cerambycidae) 
LONGLEY,  Dr.  W.  H.,  theory  of  coloiu-a- 

tion,  238-9,  301 
Lophocero'i  melanoleiwus,  169 
Lukalu  Isle,  llO-l 

butterflies  on,  125 
LuKiusA  Isle,  91-2 
LuLA  Isle,  104 

faunal  characteristics,  316 

butterflies  on,  125 
Lung  fish,  88,  160,  193 

and  Glossina,  39 
("  Lunyonkante  ")  (see  Otis),  153 
Lycaenidae   (see   also    Castalius,   Lachnoc- 
nema,   Tarucus),    103,    104,    106-8, 
110-4,  117,  120,  124-5,  199,  204 

attacked  by  birds,  111,  208,  225,  238 

directive  markings  in,  208 

larva  stored  by  Sphegid,  294 

mimetic,  103,  233 

nuptial  flight  of,  225 
Lycidae,  and  mimics,  231-2,  239,  307 
Lymantridae,  cater|illlars  of,  116,  213,  294 
(Lymexylonidae)  (see  Atractocerus) 

Madagascar,  Pseudacraea  on,  242 

("  Ma'ga  ")  (see  Elanus),  162 

"  Makindu,"  70 

("  Makwanzi  ")  (see  Osprey),  161 

Malacodermidae,  231-2 

Malaria,  11,  17 

"  Mai  de  Cadcras,"  14 

Mantidae,  311-2 

on  spider  islands,  102,  105,  109,  110,  124 

and  Asilidae,  interchangeable  functions, 
120,  124 

enemies  of,  172,  203 

anticryptic,  203,  311 
Mantispa,  285,  310,  311 
Marida  Isle,  115,  182 

butterflies  on,  125 
Markings,  directive,  207-9 

terrifying,  220-1 
JLVRSHALL,  Dr.  C,  54 
Marshall,  Dr.  G.  A.  K.,  on  Hornbill,  168 

frog  and  snake,  192 

seasonal  variations,  201,  261 

relative  edibility,  217 

Lycoid  insects,  231-2 

birds  and  butterflies,  236 

Mantispa,  311 
Masovwi  Isle,  122 
Mastiqophora,  11,  12 
Maungwi;  Isle,  107-8,  113 
Megaponera  foetens,  absent  from  islands, 

282-3 
Meinertzhagen,     Maj.    E..,     on    island 

Situtunga,  92,  139 
Melinda  petivcrana,  106,  233 


INDEX 


329 


Melipotia,  absent  from  islands,  304 
Melittophagus  mendioimUs  (see  also  Bee- 
eater),  171-8,  237 
Mendelian  relationships,  Punnctt  on,  268-9 
in  Ps.  eurytus,  Poulton  on,  263 
and  intermediate  forms,  269-270 
Merops  supercilioxus  (see  also  Bee-eater), 
171-2 
Bionomic  relations  with  OlossiJia,  310 
Mesoplatys  ochroptera,  122 
Meteorology,  76,  91 
Methoca,  303 
Mfumbiro  Mts.,  68 
Millipede,  320 
MiUogramma,  302 
Milvus  aegyptius,  162 
Mimacraea  poultoni,  103 
Mimicry,  195,  225,  230 
examnles  of  (see  also  Ps.  eurytus),  227-8, 

231-3,  238,  307-11 
and  Natural  Selection,  226,  231-5,  266, 

268 
analogous  to  special  procrypsis,  234 
depends  upon  experimental  tasting,  230 
modifications  caused  by,  228 
imaginary  mammalian  case,  229 
Mimics,  225 

polymorphic,  242 

occur  with  models,  228,  250,  251 

numerical  relation  to  models,  226,  229, 

265 
variations  in  absence  of  model,  256-9, 

262,  273 
pattern,    not    species,    depends    upon 

model,  262-3,  273-5 
may    retain    ancestral    appearance    m 

parts  not  seen,  226-227 
behaviour  of,  102,  226,  243,  308 
disregarded  by  wagtail,  238 
origin  by  mutation  or  fluctuation,  241, 
270,  271 
Models,  225 
numerical   proportions   to   mimic,    226, 

266,  267 
behaviour  and  habits  of   226,  238   239, 
243 
Molluscs,  97,  103,  115,  184  321-2 

attacked  by  Dorylus,  279,  280,  321-2 
Mombasa,  Ps.  eurytus  at,  252-4 
Mongoose,  168 

tricked  by  goose,  142 
(Monitor)  (see  Varanus) 
Monkey.  114,  117, 131-7 
on  Nkosi  Isle,  92 
language,  132-3 
intelligence,  135 
imitativeness,  135 
and  Tortoise,  135 

and  grasshoppers,  mantis,  136,  203 
and  alarming  inse^^ts,  136,  221 
Mononyx  grandicollis,  204 
Moorhen,  111,  117,  122, 153 
Morgan,  T.  H.,  272 
Mosquitoes,  97,  119,  315 
Moth,     196-9,     207,     213-4,     220,     222, 

232-3,  239 
Mtiomu  Islet,  121-2 
Mud-flsh,  79,  193 

("  Mujolo  ")  (see  Bee-eater,  Kingfisher),  169 
MuLLER,  Fritz,  195 

on  Common  Warning  Colours,  229-30 
on  Scent  Scales,  222 
Muscicapidae  (see  also  Flycatcher),  173-5 
Musophaga  rossae,  119,  165 
(Mutation)  (see  Variation) 
Mutation  theory,  239-40 
diflaculties  of,  198,  240 
and  Darwinism,  198,  262,  268-72 


Mutation,  and  intermediates,  269-71 
mutations  should  not  retrogress,  241 
does  not  account  for  absence  of  pro- 
cryptic  mimics,  240 

Mutilla,  51,  287,  303 

Myriapoda,  319-20 

Myrmarachne  Joenissex,  233,  227-8 

("  Nabubi  ")  (see  spider),  318 
"  Nagana,"  9,  14,  18,  20,  21 

compared  with  Sleeping  Sickness,  24,  25 
("  Nakibengeyi  ")  (see  Fire),  77 
"  Namugoya,"  190 
Natal,  Ps.  eurytus  in  245-6,  249,  254, 

259   262—3 
Neave,  Dr.  sTa.,  247-52 
(Nectarhiiidae)  (see  Sun-bird) 
Nepa  cinerea,  protozoal  parasite  of,  patho- 
genic to  mouse,  16 
Nephila,  numbers  of,  on  islands,  102,  103, 

105,  107,  109-23,  318 
Neptidopsis,  114 
NeiHis,  105-6,  114 
Nest,  Ant's,  227,  276,  282 

Birds',  107,  150,  158,  161,  174 

Crocodile's,  90,  98,  115,  122,  181-2 

Fish's,  194 

Fossor's,-  288-90,  294-7 

Varanus',  98,  118,  183 

Wasp's,  284-6 
Nettopus  auritus,  150 

Neuro-muscular  system,  modifications  of, 
in    deceptive    resemblance,    196-8, 
226-8 
Neuroptera,  309-11 
Nga:\iba  Isle,  99-100,  143,  180-1,  188 

Olossina  on,  47,  100 

butterflies  on,  125 

Ps.  eurytus  on,  273-5 

Situtunga  on,  140 
(Nightjar)  (see  Caprimulgus) 
Nile,  R.,  67-8 
Nkosi  Isle,  90-92,  131 
Noctuidae,  101,  207 
{Notodontidae)  (see  Scalmicauda) 
NSADZi  Isle,  100-1,  204,  288,  307 

Olossina  on,  44 

breeding  places  of,  56 

Situtunga  on,  28-9 
Nuptial  flight  of  butterflies,  224-5 
Nyasaland,  Trypanosomiasis  in,  9 

Ps.  eurytus  in,  246,  249,  254 
Nymphalinae  (see  also  Pseudacraea),  103-6, 
110-2,  114,  116,  120,  125,  242 

as  mimics,  233 

courtship  and  nuptial  flight  of,  223-5 

attacked  by  birds,  225 

("  Obuduli  ")  (see  Shrimp),  320 

"  Obusaji-saji,"  100,  283-4 

("  Obutwa-twa  ")  (see  Erlangea),  107 

Odynerus,  286 

Qir.ophylla  smnragdina,  100,  283 

mimics  of,  233,  227-8 
(Oedicnemus)  (see  Stone  Curlew) 
"  Oluzibaziba,"  58,  70,  95,  117,  121,  122 

food  of  Situtunga,  99,  138 
("  Oniugalati  ")  (see  Chrysopkyllum),  98 
"  Omukene,"  194 
"  Omukoba,"  99 
"  Omukwakula,"  105 
"  Omululu,"  99 
"  Omusali,"  95 

("  Omusenene  ")  (see  Podo:arpus),  115 
("  Omusoke  ")  (see  Waterspout),  75 
("  Omutimwa  ")  (see  Stone  Curlew),  150 
"  Omuvuvumye,"  70,  122 
"  Omuziru,"  99 


330 


INDEX 


Onomatopoeia,  152-3, 166-168, 173,  303 

Ophiderea,  207 

Orthoptera,  311-4 

OsnoRN,  Prof.  H.  F.,  19 

Osprey,  161 

Otis  melanoyaster,  153 

Otter,  140-1 

Owl,  81,  163-4 

Pachnoda  sinuata,  121 

pactolicus,  239 

Palm,  70,  105 

Paltothyreus  tarsatus,  50,  172,  281-2 

Papilionidae,  98,  106,  125 

directive  markings  in,  208 

as  mimics,  233,  238 
Papilio  dardanus,  114 
form  diomjms,  273 
hippocoon,  222,  273 
trimeni,  271 
variation  in  absence  of  model,  273 
transitional  variations,  269,  271 
heredity  of  small  variations,  241 
(?  deceived  by  mimicry,  221-2 
S   ?    are  pseudaposematic,  240 
nuptial  flight,  225 

caterpillars   resemble   bird-droppings 
199 

demodocus,  120 

leonidas,  106,  114,  233 

polytes,  269 

rklleyanus,  238 

umndce,  114 
Papyrus,  69,  117,  118 
(Paradise  flycatcher)  (see  TcMtrea) 
Parle  land,  68,  119 
Parrot,  81,  92,  102,  164 
Passer  (/rUeus,  177 
Passeriformes,  173 
Pasteur,  21,  220 
Pelican,  149 

Penfatomodiae  (see  also  Damarius),  215 
Pentiki,  104 

Phalacrocorax  africanus  (see   Cormorant) 
147 

lucidus  (see  Cormorant),  146 
Phasmidae,  312 
Phrosyne  brevicornis,  307 
Phi/mateus  viridipes,  212 
Pierinne,  112,  114,  120,  125,  204,  208,  213 

attacked  by  birds,  225,  237-8 

courtship  and  nuptial  flight  of,  223,  224-5 

dry  season  forms,  202 

mimetic,  226-7 
Pigeon,  103,  159 
Pinacopleryx,  202,  223 
Plaintain  eater,  103,  110,  119, 165 
Plaiiema,  98,  206,  235 

boldness  of  demeanour,  209,  233-9 

resistance  to  poison,  213 

as  models,  233,  242,  245-9,  250-4,  256 

variation  in  numbers  on  Kome,  266-7 

on  sundry  islands,  274-5 

adraHa,  253-4 

agatiice,  245-7,  249,  253,  254 

aganice  montana,  95,  205,  253-4,  274 

alcinoe,  95,  114,  205,  274 

epaea,  245,  254 

epaeu  parayea,  252.  254,  257,  274 

excisa,  248 

macarista,  97,  114,  205,  247-8,  250,  254, 
256-7,  274-5 

macarista  pseudeuryta,  247,  254,  262 

poggei,  105,  114,  250,  254,  256-7,  274 

tellus,  233,  238-9,  251,  254,  257,  274 
Pkitysteira  jacksoni,  175,  275 
Plectropterus  gambensiD,  150 
Plover,  81, 150-2 


Plusia,  199 
Podocarpus,  115 
Pomatorrhynchus,  175-6 
PompiUdae,  232,  286-7,  300-2 
aposematic  flight  of,  301-2 
PONDOLAXD,  Ps.  eunitus  in,  253-4,  245-7 
(PORTER)  (see  Fantham  and  Porter) 
PouLTON.   Prof.   E.   B.,   classification  of 
colouring,  195-6,  206,  230,  234 
on  limitations  of  Natural  Selection,  197, 

226-7 
on  seasonal  variation,  202 
on  relative  edibility,  217 
on  enemies  of  protected  insects,  219 
on  terrifying  marks,  220 
on  scent  of  butterflies,  223 
on  same  effect  produced  by  different 

means,  231 
on  inheritance  of  small  variations,  241 
on  flight  of  Pseudacraea  and  Limenitis, 

243 
on  Mullerian  mimicry,  243,  248 
on  forms  of  Ps.  eurylus,  249-250 
on  relaxation  of  selection  in  absence  of 

model,  256-0,  262-3,  266.  273 
on  Mutation  theory  versus  Darwinism, 

262,  271 
on  Drosophila,  272 
on  "  painting  out,"  308 
(Pratincole)  (see  Galactochrysea) 
Precis,  seasonal  changes  of,  201-2 
courtship  of,  223-4 
archesia,  111,  120 
clelia.  111,  120 
sesamus,  201 
Problepsis  aegretta,  199 
Protomo)mdi)ia,  12 
Protopterus,  39,  88,  160, 193 
Protozoa,  classification  of,  11 

causing  disease,  11 
Pseudacraea,  allied  to  Limenitis,  243 
distastefulness  of,  243-4,  263 
distribution  of,  242 
flight  of,  243 
habits  of,  244 
boisduvalli,  114,  233 
deceptor,  242 

eurytus,  distribution  of,  235,  241,  245 
genital  armature  of,  255 
life  history  of,  259-61 
bred  families  of,  264 
polymorphism    of,    244-5,    255,    259, 

261-2 
transitional  forms  of  241,  245,  247-8. 

252,  254-9,  260-1,  267 
mimicry  deceptive,  242-3,   246,  252, 

255,  263 
never  mimetic  of  a  cryptic  species,  240 
l)artially  protected,  262-3 
aposeme  of,  246-9,  251-3 
Mendelian  relationships,  263 
form  eurytus,  244,  245,  247,  251,  253, 
254-5,  262 
the  ancestral  form.  257 
form  hobleyi,  103,  106,  114,  247,  249, 
250-2,  254-7,  262,  274 
a  stable  form,  264 
a  secondary  mimic  of  kuenowi,  248 
flirting  with  terra,  259 
lorm  imitator,  242,  245,  246,  247,  249, 
254-5 
a  fi.xed  form,  259,  262-3 
life  history  of,  259 
form  impleta.  252 

form  obscura,  104,  252,  254-7,  263,  274 
an  unstable  form,  252,  264 
inefficient  mimic,  252 
flirting  with  terra,  259 


INDEX 


331 


Pseudacraea  'eurtjtus,  lorm  poggeoides,  250, 
252,  254-5,  257,  262 
form  togersi,  249,  252,  253,  254-5,  263 
form  terra.    106,    245,  249,  251,  252-7, 
263,  274-5 
an  unstable  form,  264 
perfection  of  mimicry,  251 
flirting  with  hobleyi,  259 
behaviour  of,  239 
form  tlrikensis,  103,  114,  245,  247,  248-9, 
250,  254,  257,  262,  274 
a  stable  form,  264 
kuenowi,  245,  248 
lucretia,  104,  106,  114 

flight  like  that  of  Neptis,  105 
poggei,  flight  of,  243 
simulator,  242 
Pseudocreobotra  ocellata,  203,  311 
Psychidae,  evidence  of  insularity,  100,  106 
(Puff-adder)  (see  BUis) 
PuNNETT,  Prof.  R.  C,  on  "  Mimicry  in 
Butterflies,"  231 
on  birds  and  butterflies,  235 
on  Mutation  theory  versus  Darwinism, 

268-9 
on  Mendelian  heredity  and  intermediates, 
270-1 
Python,  116,  188-9 
source  of  food  for  G.  palpaUs,  39 

Quail,  160 

(Eace,  insular)  (see  Islands,  faunal  pecu- 
liarities) 
Rat,  abundant  on  certain  isles,  95,  112,  116 

Trypanosome  of,  13, 18 
Rails,  153 

Reedbuck  and  T.  ffambiense,  27 
Resuvu  Islet,  97 
Rhodesia,  Trypanosomiasis  in,  9 

Ps.  eurytus  scarce  In,  245 
Rhodogastria  leucoptera,  210-1 
Ehopalocampta  chalybe,  103,  106,  114 

forestan,  106 
Ridley,  H.  N.,  283 
Robertson,  Miss,  26,  61 
(Robin  chat)  (see  Cossypha) 
Roller,    functions    interchangeable    with 
Bee-eaters,  171 

absent  on  islands,  167 

eat  Copridae,  218,  306 
RuJiFUA  Isle,  123-4,  183 

butterflies  on,  125 

(Safari  ant)  (see  Dorylus) 

Salamis,  103-6,  114 

SaliUHca  egeria,  232 

Salivary  glands,  of  Glossina,  Trypanosomes 

in,  17,  26 
Sallicidae,  228,  233 
Salvia,  99.  105,  112,  119 
(Sandpiper)  (see  Tringoides) 
(Sand  wasp)  (see  Fossor),  286 
Sanga  Isle,  101-3,  164,  214 

Glosntia  absent  from,  34,  102 

butterflies  on,  125 
Sarcodina,  11 
Saturnidae,  caterpillars  of,  199,  201.  213 

terrifying  markings  of,  220 
Satyrinae,  103,  125,  213 

attacked  by  birds,  225 

directive  markings  of,  208 

nuptial  flight  of,  225 
Sealmicauda  niveiplaga,  197 
Sceliphron  spirifex,  295-8 
Scent,  produced  by  male  butterflies,  222-3 
Schizorhis,  165 
Schizotrypanum  cruzi,  14 


Scoliidae,  12 J,  231,  287,  303 

evidence  of  insularity,  103 
Scopus  umliretla,  155-6 
Scorpion,  scarce  on  islands,  321 
Sege  Isle,  116 

butterflies  on,  125 
Segregation,  270,  272 
("  Sekanyolya  ")  (see  Ardea  melanocephala), 

158 
("  Sekoko  ")  (see  Cuculm  solitarius),  166 
Selection,  Natural,  196,  241,  262 

produces  no  more  than  is  necessary, 

197,  202,  226-7 
produces    same    effect    by    different 

means,  231 
produces  more  detailed  likeness  than 

chance  can,  234-5 
originates  nothine,  231 
and  the  Mutation  theory,  262,  268-9 
of  mimic  relaxed  in  absence  of  model. 
256-9,  262,  266,  273 

Sexual,  209,  221-6 
SELOrs,  F.  C,  35,  236 
Sematic  colouration,  195 
("  Semirindi  ")  (see  Cormorant),  147 
("  Semukutu  ")  (see  Enyaliopsis),  313 
"  Semutundu,"  194 
Shelford,  R.  W.  C,  on  flying  snake,  189 

on  mimetic  spider,  227 

on  Lycoid  insects,  232 
Shrike,  175-6 
Shrimp,  320 

("  Siafu  ")  (see  Dorylus) 
SiDGWICK,  A.,  199 
Siluridae,  141,  193-4 
Silver,  markings,  199,  319 
Simuliidae,  80,  151 
Simulium  damnosum,  315 
SiNDiRO  Isle,  118,  183 
Situtunga,  88,  91-2,  101,  117,  137-40 

and  Trypanosomes,  15,  27-9,  41 

and  G.  palpalis,  28-9,  36,  61 

Meinertzhagen  on,  139 

Speke  on,  137-8 

swimming  powers,  61 

Food  of,  99 
(Skipper)  (see  Hesperidae) 
Sleeping    Sickness,    confined    to    tropical 
Africa,  1 

symptoms  of,  1-2 

closely  allied  to  animal  diseases,  2,  24-5 

earliest  account  of,  2-5 

enlarged  glands  in,  6 

first  associated  with  Trypanosome,  6,  23 

spread  of,  6-9 

Royal  Society  Commission  on,  7,  23 

cause  and  carrier  of,  7,  23-4 

checked  by  depopulation,  8 

in  absence  of  G.  palpalis,  9 

in  W.  Africa,  17 

eradication  of,  61-5 
Slow  worm,  190 
Slugs,  321 

as  evidence  of  insularity,  103,  115 

attacked  by  Dorylus,  279 
Snails,  attacked  bv  Dorylus,  279 
Snakes,  95-6,  116, 187-93 

danger  of,  187 

evolution  of  poison  of,  191-3 

as  food  of  G.  jmlpalis,  39,  188 
Snipe,  152 

("  Sombabyuma  ")  (see  Ciconia),  155 
Spalgis  pilos,  107 
(Sparrow)  (see  Passer) 
Speke,  J.  H.,  67,  137,  139 
Spheqidae,  286-7,  294-300 

enemies  of,  302 

noise  of,  when  working,  295,  298 


832 


INDEX 


Sphegidae,  methods  compared  with  Pom- 
pilidae,  300 

unusual  nesting  place  of,  295 

prey  of,  294 

Lycoid,  232 
Sphex  margiiiatus,  302 

pelopaeiformis,  295 
Sphinc/omorpha,  221 
Spider  (see  also  Nephila),  120,  318-9 

eaten  by  Sunbird,  177 

and  Dorylus,  279 

anticryptic,  203 

mimetic,  227-8 

stored  by  Sceliphron,  297 

curious  web  of,  318-9 
Spider  islands,  102,  105,  107,  109,  114-5, 
118,  120,  124 

scarcity  of  birds  on,  102,  103,  105,  120, 
124 

predaceous  insects  on,  108, 105, 109, 120 
124 
Spines  of  caterpillars,  213 
Spirochaetes,  18 
Spizdetus  coronatus,  164 
Sporozoa,  11 

Starling,  glossy,  absent  from  islands,  176 
(Stick  insect)  (see  Phasmidae) 
•  Stilt,  152 
(Sthik  ant)  (see  PaUothpreus) 
Stone  Curlew,  97, 160-1 
Stork,  146,  155 

Common,  155 

(open  bil'.ed)  (see  Anastomus) 

(saddle  billed)  (see  Epkippiorhynchus) 

(whale  headed)  (see  Balaeniceps) 
Storm,  73-5,  82-3,  91-2,  101,  123 
Stylogaster  and  Eciton,  281 
Sunbird,  103,  105,  111-3,  115, 121-2, 124 

caught  in  web  of  Nephila,  109 
Sunflower,  70,  122 
Surra,  14,  18 
Swallow,  108,  113,  117 
SWYNNERTON,    C.    F.    M.,   ou   blrds   and 
butterflies,  236-7 

on  relative  edibility,  217 
(Syntomidae  (see  Epitoxis) 
Syntomosphi/rum  glossince,  51-2 

Tabanidae   (see   also    Chrysops,  Tabanus), 

carriers  of  Trypanosomes,  18 
Tabanus  thoracinus,  293 

variabilis,  315 

variatus,  97 
Tachinidae,  220,  286,  288,  297-8,  315,  316 
Tarucus  telicanus.  111,  121,  124 
Tasting,  experimental,  212-3 
Tavu  isle,  96-7,  180,  182-4,  189 

Glossina  on,  32,  47-9 
breeding  places  of,  55 

butterflies  on,  125 
Tchitrea  emini.  102,  103, 105,  110,  115  116 
124,  171,174 

local  island  races  of,  275 

nest  of,  174 
Tdipna  nyanzfp,  233 
Teracolu^,  114 

seasonal  forms  of,  202 

bricht  colours  of,  208-9 
Terias,  114 

colouration  of,  204 

attacked  by  bee-e<atcr,  173,  237 
Termites.  80,  97,  162 

absent  from  some  'slands,  96,  112 

prey  of  Megavonpra,  283 
(Tern)  (-(ce  Ihidronhelidon) 
TiiAYER,  A.  H.,  on  colouration,  204,  238 
Thrush,  112,  119,  179 
Ticks,  scarce  on  islands,  319 


Tiger  moth,  213 

Tipulidae.  310 

ToKwi  Isle,  121-2 

Tortoise,  39,  135,  186 

(  Tragelaphus  spekei)  (see  Situtunga) 

Trees  (see  also  '"  Ekirikisi,"  Fig-tree,  Podo 

carpus\  70,  72,  95,  98-9,  104-5 
Trilncha  obliquissima,  caternillar  of,  215-6 
Trimen,  n..  195,  245,  253  " 
Thing  mu«eum.  Ps.  eurylus  in,  246,  249 

253-4 
Tringoides  hypoleucos ,  146, 151 
Trypanoplasma,  12,  13 
Trypanosoma,  12-14 
brucei,  14,  16 
becomes  rhodesiense  by  mutation,  17 
believed    to    be   mechanically   trans- 
mitted, 23,  25 
carripd  by  Q.  morsitam,  23 
natural  hosts  of,  26 
equiiium,  14 
eguiperdum,  14 
evansi,  14 
gambiense,  13, 14,  24 

possibly  carried  by  G.  warsitans,  9 
and  natural  hosts,  15,  26-9 
life  cycle,  25-6,  40 
still     pathogenic     on     depopulated 
islands,  28 
grayi,  40 
lew!  si,  13 
nigerienae,  15,  17 
rhodesiense,  10,  14,  17 
vivax,  13,  40 
Trypanosomes,  and  Sleeping  Sickness,  7,  24 
position  in  animil  kingdom,  11 
near  relations,  12 
general  appearance,  13 
human,  6,  9,  10,  14,  23 
do  not  always  cause  disease,  15 
hosts  of,  15-17 
life  cycle  of,  17,  25,  40 
and  bacilli,  in  gut  of  fly,  40-1 
carriers  of,  18 

compared  with  Spirochaetes,  18 
and  direct  inoculation,  23 
no  hereditary  transmission  of,  25 
Trypanosomiasis,  human,  2,  23 
in  Rra7il,  14,  18 
in  Nigeria,  15 
in  Rhodesia,  9,  10 
compared  with  Nagana,  24-5 
acriiiired  imranuity  in,  17 
Tse-tse  (sec  also  Olossina),  in  Uganda,  8 

origin  of  name,  19 
(Tsetse  fly  disease)  (sec  "  Nagana  ") 
(Tufted  Umbre)  (see  Scopus) 
TULLOCH,  Lt.,  7 
("  Tutuma  ")  (see  Coucal),  166 

Uganda,  Ps.  eurytus  in,  245,  247-8,  250-2, 
254-9,  262-3 
Sleeping  Sickness  in,  7,  8 
Ukerewe  Isle,  67 
Vranothauma,  110 
Usamhaka,  Ps.  eurytus  from,  254 

Van  Someren,  Dr.,  171 
Varanus,  182-5 

as  food  of  0.  palpalis,  37-8 

nesting  places,  98,  118,  183 

basking  places,  183 

food  of,  151,  184-5,  320 

relations  with  crocodile,  183 

numbers    on    different    isles,    96,    99 
109-113,  115,  116,  118-9,  122,  124 
Variations,  continuity  in,  270 

geographical,  235,  241,  247,  262 


INDEX 


333 


Variations,    heritable    fluctuations,    241, 
268,  271-2 
MutationB,  240-1,  268-9,  270-2 
of  mimic  in  absence  of  model,  256-9, 

262,  267,  273 
seasonal,  201-2 
Transitional   forms,     in     P.     dardanus, 
269-71 
absent  in  P.  pohjtes,  269 
in    Ps.    eurytus,     proportions    of,    in 

different  localities,  265 
survive  in  absence  of  models  (see  Ps. 

eurytus),  266,  273 
and  Mutation  theory,  268-271 
Vertigo,  322 

Victoria  Nyan.ta,  67,  69-71 
climate  of,  72 
fall  in  level  of,  69 
signs  of  weather  on,  76-80 
sounds  of  life  on,  80-81 
storms  on,  73-5,  82-3 
Vinago,  159 
Vitrina,  321 
Viverridae,  141-2 
Vulture,  absent  from  islands,  164 

Wagtail,  121 

attacks  on  butterflies,  111,  208,  238 
Waitwe  Isle,  116,  117 

faunal  characteristics,  116 

Glossina  on,  117 
("  Waka  ")  (see  Paltothyreus),  281 
Wallace,  195 

on  struggle  for  existence,  218 
Warbler,  102,  178 
Warning  colours,  195,  206,  230 
Wasps,  97,  108,  207,  284-6 

prey  of  Bee-eater,  172 

syn-aposematic,  230,  232 
Waterbuck  and  T.  gambiense,  27 
Water  lilies,  69,  101 


(Water  scorpion)  (see  Nepa) 
Waterspout,  75 
Wavuziwa  Isle,  115-6 

faunal  characteristics,  116 

Olossina  on,  115 

butterflies  on,  125 
Weather  prophets,  77-80 
Weaver    birds,    102-3,    108,    111-3,   115, 

117,  120-2, 176 
Weevil,  196 
Wema  Isle,  68, 113-5 

Olossina  on,  51,  57,  114 

butterflies  on,  114,  125 

monkeys  on,  131 
West  Africa,  Ps.  eurytus  in,  245,  247-8, 

251,  254,  262 
Wiggins,  C.  a.,  collection  of  Ps.  eurytus 

255,  259 
Wind  (see  also  storms),  76,  90 
("  Wonzi  ")  (see  Spizaetus),  164 
(Wood  hoopoe  (see  Irrisorinae) 
Woodlice,  321 
Woodpecker,  78 
Wood  swallow,  236 
Woolly  bear,  213 

Xenetomorpha  carpenteri,  228 
Xylocopidae,  303 

Yempata  Isle,  117-8 
accessory  isle,  117 
Glossina  on,  32,  118 
monkeys  on, 131 

Zeltus  antifaunus,  114 
ZiGUNGA  Isle,  113,  116 

faunal  characteristics,  113 
ZiRO  Isle,  108-9,  141 
Zonocerus  elegans,  215 
Zygaenidae,  213,  230,  232 


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WOKING  AND  LONDON