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various  species  of  Dactylopiids , not  to  speak  of  how  useful  proved 
also  in  the  Hawaiian  Islands  the  introduction  of  Coelophora 
inaequalis  in  destroying  the  numerous  aphids  which  destroyed 
many  plants. 
Such  examples  are  certainly  fine,  demonstrative,  but  also  ap- 
pear simple  and  their  solution  could  not  require  very  special 
ability  once  the  principle  was  recognized  of  the  possibility  of  find- 
ing useful  parasites  against  harmful  insects,  as  for  instance  Icerya 
in  their  home  country. 
In  the  case  of  Cryptolaemus,  Coelophora,  and  Platyomus  Koe- 
bele  demonstrated  also  how  it  is  possible  to  fight  with  insects 
parasitic  of  species  of  a certain  region  insects  of  related  species 
or  of  other  genera  native  of  other  countries,  and  therewith  in- 
stituted another  noteworthy  step  in  the  natural  method  of  control, 
but  still  he  had  to  prove  to  the  world  how  much  confidence  has  to 
be  placed  in  the  auxiliaries  offered  by  nature. 
In  this  new  case  he  needed  the  efficient  assistance  of  a profound 
connoisseur  of  insects  of  every  group,  of  a diligent  and  patient 
collector,  observer  and  breeder,  that  is  of  Dr.  C.  L.  Perkins,  as 
well  as  an  able  systematician  of  Hemiptera,  Kirkaldy. 
The  occasion  for  this  new  and  great  experiment,  which  to  relate 
gives  me  great  pleasure,  was  offered  by  Perkinsiella  saccharicida , 
Kirk.,  Hemipteron  of  the  family  Asiracidae  (Fulgoroidea). 
This  Perkinsiella  is  a small  insect  four  to  six  millimetres  long. 
It  deposits  its  eggs  in  or  near  the  mid  rib  of  the  leaf  and  also 
on  the  stem  of  sugar  cane.  The  larvae  and  adult  live  on  the 
juice  of  the  cane.  The  damage  it  does  is  direct  and  indirect;  the 
first  is  caused  by  the  deposition  of  the  eggs  and  the  subsequent 
openings  of  the  larva  which  has  to  work  its  way  through  the  epi- 
dermis, and  by  the  abstraction  of  nutritive  liquids  caused  by  the 
larvae  and  the  adult.  The  indirect  damage  is  due  to  the  smut 
and  other  fungi  which  develop  on  the  cane  plants  in  excrementa 
of  Perkinsiella,  which  contain  sugary  substances. 
In  the  case  of  serious  infection  if  the  cane  plants  are  small  they 
may  be  completely  destroyed,  if  they  are  well  enough  advanced 
they  lose  many  leaves,  do  not  reach  complete  development,  and 
yield  a crop  smaller  of  course  in  proportion  as  the  damage  is 
greater. 
Perkinsiella  saccharicida  was  seen  for  the  first  time  by  Perkins 
who  collected  several  specimens,  but  not  until  the  end  of  the  year 
1901  or  the  beginning  of  1902  was  it  found  harmful  to  sugar  cane 
on  the  islands  of  Oahu  and  Kauai.  In  the  month  of  November, 
1902,  Perkins  wrote:  “This  little  insect  is  very  injurious  to 
sugar  cane  and  its  destructive  activity  threatens  to  surpass  that 
of  the  insect  which  bores  galleries  in  the  cane  (S  phae  nop  horns) 
The  subsequent  events  happened  briefly  as  follows : On  all 
the  sugar  plantations  Perkinsiella  spread  rapidly  causing  such' 
enormous  damage  that  Van  Dine  calculated  it  in  1903  to  amount 
to  $3,000,000.  Rightly  alarmed  the  sugar  planters  pressed  the 
