356  Annual  Report  for  1909  of  the  Zoologist. 
The  difficulty  with  corn  pests  is  this,  that  when  the  presence 
of  the  pest  is  observed  the  harm  is  almost  invariably  already 
done.  No  conceivable  treatment  will  restore  oat-plants  which 
have  been  killed  by  frit-fly  maggots.  Occasionally,  if  a crop 
is  seen  to  be  doing  badly  at  an  early  stage,  a dressing  of  some 
forcing  manure  will  enable  some  of  the  plants  attacked  to 
survive  the  injury  done  them,  and  will  so  minimise  the  loss, 
but  beyond  this,  any  remedial  measures  are  impossible.  Pre- 
ventive measures,  therefore,  alone  remain,  and  even  here  it  has 
to  be  borne  in  mind  that  the  pest  is  by  no  means  certain  to 
recur  to  the  same  extent  the  next  season.  It  may  be  much 
reduced  by  a concomitant  increase  in  the  insects  which  prey 
upon  it,  and  the  weather  conditions  may  not  favour  it.  Still, 
any  measures  for  its  destruction  which  can  be  conveniently 
adopted  in  the  ordinary  course  of  cultivation  are  clearly  desir- 
able, and  the  flrst  point  to  be  considered  is  the  whereabouts 
of  the  pest  when  the  crop  is  carried — whether  the  pest  is  carried 
away  with  the  crop,  or  left  behind  in  the  stubble.  In  the  case 
of  Hessian  fly,  for  instance,  most  of  the  insects  are  carried  from 
the  fleld  in  the  straw,  and  quantities  of  the  “ flax  seeds  ” may 
be  found  and  dealt  with  in  the  process  of  threshing.  With 
frit-fly,  since  the  maggot  works  at  the  bottom  of  the  stalk,  it  is 
the  stubble  which  demands  attention.  Ploughing  it  in  deeply 
with  a skim  coulter  is  certain  to  account  for  such  of  the  flies  as 
are  still  in  the  chrysalis  state  at  the  time  of  harvest,  but  the 
chrysalis  stage  is  not  long,  and  many  will  have  already  emerged 
to  lay  their  eggs  on  wild  grasses.  The  only  way  to  destroy  the 
whole  brood  would  be  to  plough  in  deeply  in  June,  and  this 
plan  should  be  adopted  in  the  case  of  very  bad  attack,  where 
there  seems- little  likelihood  of  obtaining  a crop  worth  reaping. 
Finally,  early  sowing  is  desirable  if  weather  conditions  at  all 
admit  of  it.  It  is  always  the  late-sown  crops  which  suffer  most. 
Root  Crops. 
The  root  crop  pests  inquired  about  presented  few  points  of 
special  interest.  “Leather-jacket”  (the  grub  of  the  crane-fly, 
Tipula  oleracea)  was  the  pest  most  frequently  complained  of. 
It  has  frequently  been  dealt  with  in  these  Reports,  and  members 
may  be  referred  to  the  Journal  for  1908,  page  327,  for  an  account 
of  it.  There  were  cases  of  attack  by  root-maggots  {Anthomyia), 
mangold-fly,  turnip  gall-weevil,  and  millipedes.  Mangolds 
appeared  to  be  the  crop  which  suffered  most,  and  it  was  in 
connection  with  these  roots  that  a curious  case  of  “ mistaken 
identity  ” occurred.  A number  of  beetles  sent  from  a mangold 
crop  proved  to  be  the  “ sexton  beetle,”  Necrophorus  vestigator. 
This  insect  is,  of  course,  a carrion  feeder,  and  quite  harmless 
to  vegetables,  and  its  presence  was  explained  by  the  fact  that 
