86 
Culicinae.  We  found  Stegomyia  (the  i 
transmissor  of  yellow  fever)  in  Baurú  and  I 
also  in  large  numbers  in  Tres  Lagoas  (Matto 
Grosso),  the  first  station  on  the  Corumbá  ¡ 
railway.  If  the  other  stations  on  the  same 
line  are  not  already  invaded  by  Stegomyia, 
it  is  safe  to  say  that  they  will  soon  be, 
as  this  mosquito  is  easily  spread  by  railway. 
In  the  ports  Tibiriçá,  Mojoli,  Mendes  and 
in  Iguassil  we  found  no  Stegomyiae.  They  are 
only  seen  when  imported,  as  they  are  not 
natives  of  that  region.  I  saw  them  again 
in  Encarnación,  Assuncion  and  San  Bernardi¬ 
no  and  on  the  earlier  part  of  the  journey. 
Stegomyia  is  found  in  Buenos- Aires,  La 
Plata  and  Montevideo.  I  am  not  sure  whether  ! 
it  occurs  in  Rio  Grande  or  not.  Only  once 
during  my  stay  did  I  see  a  mosquito  flying 
in  the  peculiar  way  which  characterises  the 
male  Stegomyia. 
The  most  troublesome  Culicidae  met 
with  on  the  journey  were  : 
Culex  fatigans  (nowadays  quinqués- 
triatus) 
Culex  confirmatus  (nowadays  scapula- 
ris) 
Culex  albofasciatus  MACQ. 
lanthinosoma  Arribalzagae 
Manso  nia  titillons 
The  common  night-mosquito,  C.  fatigans 
WIED.,  is  so  ubiquitous  that  is  hardly  seems  | 
worih  mentioning  in  which  places  we 
found  it. 
C.  scapularis  ROND.,  more  known  ¡ 
as  C.  confirmatus,  is  very  common  on 
the  Upper  Paraná.  In  houses  or  boats  in  i 
motion  it  is  not  numeousr,  but  as  soon  as 
the  latter  come  alongside  the  bank,  C.  sca- 
oularis  invades  them,  together  with  /.  Árri-  1 
balzagae.  It  is  however  only  when  one  pene¬ 
trates  into  the  depths  of  the  thickets  on  the  | 
shore,  that  the  former  becomes  really  unbear¬ 
able.  Strange  to  say,  the  larvae  of  this  spe¬ 
cies  are  seldom  found.  This  fact  and  the  fre-  | 
quent  occurence  of  rubbed  specimens  lead 
me  to  believe  that  C-  scapularis  enjoys  a 
long  life.  We  did  not  find  a  single  breeding  1 
place  of  the  larvae  of  this  species,  during 
the  whole  of  the  journey. 
From  Iguassú  to  Encarnación,  mosquitos 
are,  generally  speaking,  more  rare  ;  C.  scapu¬ 
laris  is  however  frequently  found  in  Para¬ 
guay  and  in  the  Argentine,  where  there  are 
trees. 
C.  albifasciatus  ressembles  C.  scapularis 
in  many  ways.  It  atacks  in  day-time,  even  in 
full  sun-light  and  its  bite  is  rather  painful. 
When  attracted  by  artificial  light,  it  enters 
houses  and  boats  in  great  numbers;  yet  it 
can  hardly  be  considered  a  house  mosquito. 
The  first  specimens  were  found  below  Corri¬ 
entes  ;  while  crossing  a  marshy  region  below 
Paraná,  the  boat  was  completely  invaded  by 
C.  albifasciatus.  Until  a  short  while  ago,  this 
species  was  only  known  from  the  Argentine, 
but  I  found  it  very  abundant  in  the  harbour 
of  Rio  Grande  where  it  came  on  board.  I 
caught  several  females,  some  of  which  were 
gorged  with  blood  ;  others  1  allowed  to  sting. 
The  eggs  obtained  from  them  were  laid  se¬ 
parately  and  of  the  same  shape  as  those 
of  Stegomyia.  They  sink  easily,  but  de¬ 
velop  even  under  water,  though  less  quickly. 
The  larvae  take  at  least  five  days  to  develop; 
they  have  a  short  and  stout  respiratory  tube 
and,  after  the  last  moult,  about  fourteen 
curved  compound  spines  on  each  comb.  These 
are  generally  almost  equal  but  the  basal  one 
is  shorter  and  the  two  last  ones  longer  ; 
the  tuft  corresponding  to  each  comb  is  com¬ 
posed  of  nine  bristles  and  is  nearer  to  the 
apex.  The  antennae  are  short  and  have  no 
bristles.  The  larval  stage  lasts  about  two 
weeks;  many  of  our  larvae  died,  problably 
because  the  conditions  under  which  they 
were  raised  were  defective  and  different 
to  the  normal  ones.  The  nymphal  period  is 
a  litle  less  than  three  days. 
We  found  regular  swarms  of  lanthino¬ 
soma  Arribalzagae.  It  is  not  wanting  on  the 
Lower  Paraná  and  in  Paraguay,  while  on 
the  upper  river  and  its  aflluents,  above 
Porto  Mojoli,  it  formed  a  real  line  of  defen¬ 
se,  attacking  all  the  people  who  went  on  shore 
and  invading  the  boats  lying  alongside,  fn 
some  places  the  number  of  fern  des  settling 
on  the  travellers’  clothes  surpassed  anything  I 
had  hitherto  seen,  but  luckily  only  a  few  of 
