29  3 
same  was  true  of  the  few  Frenchmen  with  the  exception  of 
Decaux. 
PROGRESS  IN  THE  NATURAL  METHOD  OF  WAREFARE  IN  THE 
UNITED  STATES. 
In  North  America  on  the  other  hand  the  new  era  for  agricul- 
tural entomology  was  initiated  about  1870  and  here  the  natural 
method  of  control  was  to  receive  its  greatest  impulse  and  was  to 
yield  its  first  surprising  results  not  only  to  the  country  which  had 
the  will  and  the  power  to  apply  it  on  a vast  scale,  but  also  to 
other  nations. 
I. — Advices  for  the  Utilization  of  Insects  Parasitic  on  Destruc- 
tive Insects  in  the  Same  Regions  in  Which  Both  are  Indigenous. 
It  has  been  seen  that  Boisgiraud  in  France  and  afterwards 
Villa  in  Italy  were  the  first  to  experiment  in  fighting  harmful 
insects  with  predatory  ones  and  that  many  authors  recognized 
also  the  great  importance  of  endophagous  parasites,  but  I believe 
that  the  American  entomologist  Riley  was  the  first  to  think  of 
protecting  the  latter  and  to  recommend  a method  by  which  the 
noxious  insects  could  be  killed  and  the  endophagi  set  free.  In 
fact  in  1871  4 in  regard  to  Mineola  indiginella,  Zell.,  an  insect 
which  attacks  apple  and  other  fruit  trees,  be  recommended  as  fol- 
lows: “The  orchadist  has  but  to  bear  in  mind  that  it  (Mineola 
indiginella)  is  single-brooded,  and  that  it  passes  the  winter  in  its 
case,  and  he  will  understand  that  by  collecting  and  destroying 
these  cases  (attached  to  branches)  in  the  dead  of  the  year  when 
the  tree  is  bare,  he  effectually  puts  a stop  to  its  increase.  If  this 
fact  were  more  generally  recognized,  we  should  see  fewer  of 
these  insects  in  our  orchards  and  nurseries.  Whether  collected 
in  the  winter  or  pulled  off  the  trees  during  the  spring  and  sum- 
mer, these  cases  should  always  be  thrown  into  some  small  ves- 
sel, and  deposited  in  the  center  of  a meadow,  or  field,  away  from 
any  fruit  trees.  Here  the  worms  will  wander  about  a few  yards 
and  soon  die  from  exhaustion  and  want  of  food ; while  such  para- 
sites, hereafter  mentioned,  as  are  well  developed  or  in  the  pupa 
state,  will  mature  and  eventually  fly  off.  In  this  manner,  as  did 
Spartacus  of  old,  we  swell  the  ranks  of  our  friends  while  de- 
feating our  foes.” 
“The  practical  value  of  this  suggestion,”  writes  Riley,  in  an- 
other place  in  1894,  “was  afterwards  completely  demonstrated 
specially  by  D.  B.  Wier,  who  at  a meeting  of  the  Horticultural 
Society  of  Illinois,  as  secretary  of  a committee  instructed  to  con- 
sider the  best  methods  to  assure  cooperation  in  the  fight  against 
insects  harmful  to  fruit-  trees,  announced  that  the  method  (of 
Riley)  gave  favorable  results.” 
4 Fourth  report,  Insects  of  Missouri,  1871,  page  4ft. 
