3i5 
entomologists  of  the  Territorial  government  to  find  a way  of 
fighting  this  fearful  pest,  which  had  it  continued  would  have  com- 
pelled them  to  relinguish  the  most  remunerative  industry  of  the 
islands. 
Fortunately  Koebele  and  also  Perkins  were  there,  both  en- 
thusiastic for  the  natural  method  of  control  and  the  only  one  they 
could  consider  in  the  present  case. 
Koebele  having  heard  from  Prof.  L.  O.  Howard  of  the  presence 
of  parasites  of  Fulgoridae  in  Ohio  went  there  in  1903  collecting 
many  species,  of  which  he  succeeded  in  raising  in  cages,  using 
Perkinsiella  as  host,,  two  Hymenoptera  of  the  family  Dryinidae 
( Hoplogonatopus  mexicanus  and  Pseudo gonatopus,  sp.). 
These  were  liberated  in  the  cane  fields  but  no  specimens  were 
observed  subsequently. 
In  the  meantime  Perkins  sought  to  ascertain  the  original  home 
of  Perkinsiella,  convinced  that  it  was  a recent  introduction.  At 
first  he  suspected  that  it  was  a species  existing  in  Java  ( Dicrano - 
tropis  vastatrix) , but,  with  the  help  of  Kirkaldy  who  could  obtain 
specimens  of  that  species,  he  established  the  fact  that  such  was 
not  the  case.  He  repeatedly  applied  to  his  correspondents  in  Aus- 
tralia and  finally,  about  the  beginning  of  1903,  he  received  from 
Queensland  several  specimens  of  a Hemipteron  which  lived  there 
on  sugar  cane,  and  which  were  exactly  identical  with  those  of  the 
Hawaiian  Islands. 
Having  therefore  ascertained  that  Perkinsiella  saccharicida  was 
of  Australian  origin,  the  Sugar  Planters’  Association  did  not  heji- 
tate  to  accept  the  proposition  to  send  to  Australia  in  search  of 
parasites  of  Perkinsiella  and  entrusted  this  task  to  Perkins  and 
Koebele. 
They  arrived  in  Australia  in  May,  1904,  and  Perkins  returned 
to  Honolulu  about  the  end  of  the  same  year  after  having  visited 
together  several  parts  of  Queensland  where  they  made  very  rich 
collections.  Koebele  went  for  another  short  time  to  the  Fiji 
Islands  in  order  to  continue  the  collection,  specially  of  Fulgoridae 
and  their  parasites. 
Perkins  and  Koebele  gave  themselves  entirely  to  the  collections 
of  Cicadoidea  and  Fulgoridea  and  their  parasites,  of  all  the  species 
they  could  find,  sending  the  largest  possible  number  of  specimens 
alive  to  Honolulu,  where  Craw  took  most  diligent  care  of  them. 
They  collected  more  than  one  hundred  species  of  parasites,  of 
which  the  following  became  acclimated  in  Hawaii : Anagrus 
(two  species  or  two  races  of  the  same  species),  Par  anagrus  (two 
species,  P.  optabilis  and  P.  perforator) , Ootetrastichus  beatus. 
These  species  are  all  of  prime  importance  because  they  are  para- 
sitic on  the  eggs  of  Perkinsiella  and  show  their  activity  also  in 
quite  distinct  parts  of  the  leaf,  thus  Paranagrus  prefers  to 
parasitise  the  eggs  deposited  in  the  mid  rib  at  the  base  of  the  leaf, 
Ootetrastrichus  also  those  of  the  mid  rib  but  in  the  high  part  of  the 
leaf,  and  Anagrus  the  eggs  in  the  leaf  proper  adjacent  to  the  mid 
