133 
I  saw  a  fly  with  a  typical  egg  cluster  on  the 
left  side  of  its  abdomen.  It  hovered  around 
the  horses  and  the  people  and  was  finaly 
caught.  It  proved  to  be  a  small  male  of  Syn- 
tliesiomyia  brasiliana  BR.  &  BERO.  and  car¬ 
ried  ten  eggs  stuck  on  solidly,  lid  downwards. 
This  fly  was  put  into  a  small  glass  tube  with 
a  piece  of  banana,  but  it  died  on  the  morrow. 
It  was  then  pinned  on  a  piece  of  pith  of 
Fatsia  papyrifera  so  that  the  eggs  might  be 
observed  and  brought  near  the  skin  of 
any  animal.  They  were  examined  every  day 
and  breathed  upon  so  as  to  imitate  the  con¬ 
ditions  found  near  the  skin  of  a  warm  blooded 
animal,  or  approached  to  the  human  skin. 
On  the  11th  the  darkening  colour,  and 
the  more  distinct  lid  of  the  eggs,  indicated 
the  development  of  the  larvae.  On  the  12th, 
the  fly  was  examined  under  low  power,  after 
having  been  breathed  npon  ;  an  open  lid  and 
the  head  of  an  emerging  larva  was  seen.  It 
was  brought  near  the  skin  of  my  forearm 
and  after  some  hesitation,  passed  on  to  it, 
where  it  was  observed  by  a  binocular  micros¬ 
cope.  It  moved  about  rather  rapidly  without 
showing  any  inclination  to  burrow.  The  an¬ 
terior  3h  ths  were  densely  covered  with  large 
and  small  thorns,  the  posterior  4/7  ths  were 
bare.  It  had  the  typical  form  of  a  Dermato- 
bia  larva  already.  The  fly  was  then  put  near 
to  the  arm  of  another  person  and  a  second 
larva  emerged,  and  tried  to  burrow  in  the 
skin.  Much  later,  another  larva  was  induced 
to  pass  on  to  the  arm  of  a  third  person,  but 
it  began  to  dry  up  before  penetrating. 
I  then  transferred  the  two  first  larva  to 
the  shaven  dorsal  skin  of  a  dog,  and  put 
the  fly  in  the  vicinity  of  the  same  ;  four 
or  five  other  larvae  emerged  almost  entirely 
from  the  eggs  and  soon  passed  on  to  the 
skin  where  they  remained  for  some  time, 
being  unable  to  penetrate  at  once.  Some 
time  afterwards  they  had  all  disappeared. 
This  experience  tends  to  prove  that  the 
non  perspiring  skin  of  the  dog  has  more  at¬ 
traction  for  the  larvae  than  the  human  skin 
in  the  same  condition. 
Partly  emerged  larvae  may  retire  into 
their  eggshells  again  and  their  lids  close  down 
over  them. 
Of  the  two  Dermatobia  1  had  caught, 
one  died  at  once  ;  the  other  one  was  impri¬ 
soned  with  a  fly  which  it  caught  several 
times,  failing  to  deposit  eggs  on  it.  It  seemed 
already  rather  weak  and  died  soon  after.  I 
found  many  rather  developed  eggs  in  both 
of  them. 
At  four  o’clock  of  the  same  day,  I  allow¬ 
ed  another  larva  to  get  on  my  skin,  but  it 
did  not  burrow;  it  was  remored  and  used 
for  a  microscopic  preparation  later  on. 
On  the  fol loving  day,  at  half-past  eight 
a.  m.  there  was  still  one  egg  with  a  larva 
in  it  which  on  being  brought  near  my  arm, 
passed  on  it  at  once  and  moved  about  fcr  a 
long  time,  almost  like  a  geometrid  larva,  with¬ 
out  trying  to  burrow.  These  movements  were 
not  felt.  On  dyubling  the  skin  over  it,  a 
slight  irritation  was  felt  and  the  larva  was 
seen  to  burrow  in  an  almost  horizontal  direc¬ 
tion.  It  took  a  long  time  to  introduce  its 
first  articles  and  an  hour  to  penetrate  up  to 
its  last  fourth,  which  remained  horizontal 
and  visible  from  the  outside,  being  only  co¬ 
vered  by  the  corneous  layer.  The  penetrati¬ 
on  of  the  larva  caused  a  slight  caustic  pain, 
unlike  that  of  a  sting.  When  the  burrow¬ 
ing  was  finished,  I  felt  nothing  more. 
On  the  next  day,  there  was  no  altera¬ 
tion  in  the  dogs  skin.  My  arm  showed  some 
redness  at  the  point  of  penetration  where  the 
last  fourth  of  the  larval  skin  still  appeared; 
it  was  apparently  empty  and  suggested  a 
moult.  From  noon  to  evening  1  felt  a  slight 
itching. 
Next  morning,  the  dog  showed  no 
signs  of  infection.  On  my  arm,  was  a  dry 
scab  at  the  site  of  penetration.  When  this 
was  removed,  there  appeared  an  extremely 
fine  orifice,  from  which  a  drop  of  serum 
could  be  expressed.  Under  the  microscope 
the  moximents  of  the  posterior  end  of  the 
larva  could  be  seen  but  it  was  retracted 
when  the  serum  was  removed.  In  the  af¬ 
ternoon  the  same  phenomena  were  even 
more  distinct.  After  being  carefully  shaved, 
the  skin  of  the  dog  showed  several  orifices 
from  which  serum  exsuded  ;  it  sometimes  con- 
