OTHER  APPLICATIONS  OF  INSECTS  IN  AGRI- 
CULTURE. 
So  far  I have  spoken  of  insects  used  for  the  destruction  of  in- 
sects injurious  to  agriculture  and  cattle,  but  I think  it  would  be 
well  to  record  in  conclusion  the  other  experiments  which  have 
been  made  up  to  now  to  utilize  insects  in  the  fecundation  of  plants 
and  in  the  destruction  of  harmful  plants. 
BOMBUS. 
Red  clover  is  one  of  the  plants  which  in  order  to  give  complete 
fructification,  needs  the  intervention  of  insects  (bees).  In  fact 
since  the  observations  published  by  Darwin  it  has  been  observed 
that  blossoms  visited  by  bees  produce  five  or  six  times  as  many 
seeds  as  those  which  are  protected. 
This  plant  was  introduced  in  New  Zealand  during  the  first  half 
of  the  last  century,  but  as  it  only  produced  few  seeds  several 
species  of  Bombus  ( B . terrestris  var.  virginalis  Kirby,  B.  hor- 
torum  L.,  B.  hortorum  var.  hctrrisellus  Kirby)  had  to  be  intro- 
duced from  England ; these  became  acclimated  and  multiplied 
greatly  helping  the  work  of  the  bees  ( Apis  melliilca  L.  and  A. 
ligiistica  Spin.)  in  fecundating  the  flowers  of  red  clover.  As 
a result  of  the  introduction  of  these  insects  as  good  and  abundant 
seeds  are  produced  in  New  Zealand  as  in  Europe. 
Several  years  ago  the  cultivation  of  red  clover  was  also  begun 
in  the  Philippine  Islands  where  it  produces  few  seeds  on  account 
of  the  lack  of  insects  fitted  for  the  fecundation  of  the  flowers. 
The  United  States  are  now  about  to  increase  the  seed  production 
there  by  sending  species  of  North  x\merican  Bombus. 
BLASTOPHAGA  GROSSORUM  GRAVEN. 
California,  the  promised  land  of  the  fruit  grower,  never  let 
an  occasion  pass  to  introduce  every  possible  variety  of  fruit  and 
even  created  under  the  ingenous  impulse  of  Burbank  a great 
number  of  new  ones,  but  it  is  to  a small  insect,  the  Hymenopteron 
of  captification,  that  they  owe  one  of  the  best  qualities  of  figs  of 
Europe. 
About  1880  there  were  introduced  in  California  by  Julian  P. 
Rixford  three  varieties  of  Smyrna  figs  and  one  capri  fig.  In  1885 
fig  seeds  from  Smyrna  were  planted  and  from  them  came  beautiful 
green  trees,  which  in  1889  had  trunks  to  to  15  centimetres  in  dia- 
meter. 
In  1890  the  Division  of  Pomology  of  the  United  States  Depart- 
ment of  Agriculture  imported  branches  of  capri  fig  from  Smyrna 
and  distributed  them  in  many  States,  including  California.  But 
notwithstanding  every  care,  the  Smyrna  figs  failed  to  mature  and 
fell  off.  Then  the  importation  of  Blastophaga  was  decided  on  at 
the  suggestion  of  G.  Eisen,  who  was  familiar  with  all  the  studies 
