321 
From  Dipterous  parasites  of  the  family  Tachinidae  many  rear- 
ings  were  made  and  very  singular  habits  observed  by  Townsend ; 
it  may  be  affirmed  that  at  least  several  species  have  becomz 
acclimatized. 
The  practical  results  of  this  grand  experiment  with  the  natural 
method  of  struggle  undertaken  by  the  American  entomologists  is 
not  yet  evident  and  cannot  become  so  for  several  years  to  come, 
but  if  nature  conceals  no  new  weapons  of  offense  and 
defense  against  which  man  would  have  to  declare  himself 
o , t 
really  powerless,  the  result,  I repeat,  of  this  grand  experiment 
cannot  be  but  the  best.  The  introduction  of  so  many  parasites  of 
Lymantria  and  of  Euproctis  will  have  saved  North  American 
arboriculture,  will  have  saved  enormous  wealth  to  all  humanity. 
coleoptera:  dendroctonus  frontalis,  zimm. 
This  Scolytid  was  very  injurious  in  1889-1892  in  North 
America  and  especially  in  West  Virginia.  It  is  indigenous  of 
those  regions  and  is  fought  there  by  various  enemies,  but  Hop- 
kins, then  entomologist  of  West  Virginia,  having  learned,  that  in 
Europe  another  Coleopteron,  Clerus  formicarius  L.  was  a very 
active  enemy  in  fighting  the  Scolytids,  intended  to  try  its  intro- 
duction to  America.  Having  obtained  the  necessary  means,  he 
went  to  Germany  in  1892  where  he  collected  more  than  a thousand 
specimens  of  Clerus,  which  he  took  with  him  to  the  United  States 
and  distributed  in  various  localities  infested  by  Dendroctonus.  I11 
the  year  following  this  insect  disappeared  almost  entirely  from 
other  causes ; of  C.  formicarius  nothing  more  has  been  heard  sub- 
sequently, and  thus  this  experiment  seems  to  have  been  a com- 
plete failure. 
galerucella  luteola  mull. 
This  Coleopteron,  which  eats  the  leaves  of  the  elm  tree,  seems 
to  have  been  imported  from  Europe  to  America  about  1837  in  the 
neighborhood  of  Baltimore ; since  then  it  has  spread  in  the  East 
from  Boston  to  North  Carolina,  has  crossed  the  chain  of  the 
Alleghany  mountains  and  continues  spreading  westward.  Not  hav- 
ing any  special  enemies  to  attack  it  in  North  America,  except  in 
some  years  the  atmospheric  condition  and  perhaps  some  bacterial 
malady,  its  damage  has  been  almost  continuous  in  the  regions  it 
occupies,  damage  easily  noticed,  consisting  in  first  skeletonizing 
the  leaves  of  the  elm  tree  and  then  its  complete  defoliation. 
North  Americans  being  perhaps  more  fond  of  trees  than  any 
other  people,  they  plant  them  wherever  possible,  even  in  cities 
along  the  streets,  besides  the  numerous  parks,  and  have  always 
sought  to  fight  Galerucella  by  spraying  with  arsenical  insecticides 
at  no  small  cost. 
But  for  several  years  Prof.  L.  O.  Howard  had  in  mind  to  intro- 
