274 
^[nnaal  Report  for  1904  of  the  Zoologist. 
TWO  INSECTS  INJURIOUS  TO  PEAS. 
Pea  Midge  {Diplosis  pisi). 
This  is  a pest  which  has  attracted  no  attention  in  this 
country,  and  is  not  mentioned  in  any  of  the  books  on  injurious 
insects.  Curtis,  in  his  Farm  Insects,  figures  a pea  pod  with 
some  of  the  maggots  inside,  but  says  nothing  about  them 
except  that  they  are  those  of  “a  small  fly.”  Yet  cases  reported 
during  the  past  season  show  that  a crop  of  peas  may  be 
pi’actically  s})oiled  by  this  insect,  which  probably  often  occurs, 
and  is  very  likely  confounded  with  the  better  known  pea  moth, 
an  account  of  which  is  given  below. 
Description  and  Life-history. — The  pea  midge  is  a minute  fly, 
with  a jjale  yellow  body  marked,  in  life,  with  dusky  bars, 
which  almost  disappear  soon  after  death.  The  two  wings 
have  a dark  appearance  on  account  of  the  numerous  black 
hairs  with  which  they  are  clothed.  The  insect  passes  the 
winter  in  the  mature  condition,  anti  lays  eggs  in  the  pea 
blossom.  The  tiny  maggots  which  hatch  out  enter  the 
oleveloping  pods  and  almost  exactly  resemble  those  of  the 
pear  midge,  being  white  and  legless,  and  capable  of  jumping 
by  applying  together  the  head  and  tail  and  separating  them 
suddenly. 
The  maggots  do  not  bore  into  the  individual  peas  like  the 
much  larger  caterpillars  of  the  pea  moth,  but  they  feed  on  their 
surface  and  on  the  lining  of  the  pod,  stunting  its  growdh,  and 
giving  it  a diseased  and  foul  appearance.  Externally  the 
pod  becomes  marked  with  yellow  or  white  blotches,  often 
greatly  distorted  ; and  finally,  the  wall  becomes  perforated 
or  sj^lits  open,  giving  exit  to  the  grubs,  which  distribute 
themselves  over  the  ground  by  jumping,  and  then  enter  the 
surface  soil  to  turn  into  “puparia,”  or  chrysalids,  from  which 
the  flies  come  out  in  about  a month. 
The  actual  harm  to  the  peas  themselves  is  slight,  and  a pod 
containing  numerous  maggots  may  display  a row  of  fairly 
healthy-looking  seeds ; but  even  in  this  case  the  insect  is  a 
great  nuisance  on  account  of  the  trouble  of  collecting  the  peas 
from  the  midst  of  a crowd  of  repulsive-looking  maggots.  But 
the  distortion  and  arrest  of  growth  of  the  pods  are  still  more 
serious,  and  a badly  infested  row  of  peas  affords  so  reduced 
a crop,  and  this  so  fouled  with  maggots,  that  it  is  not  worth 
picking. 
Treatment. — When  the  pest  occurs  in  field  crops  the 
ordinary  rotation  is  probably  a safeguard  against  the  danger 
of  recurrence.  It  is  in  the  vegetable  garden  that  it  is  most  to 
be  feared,  for  the  flies  have  not  far  to  go  to  next  year’s  crop 
of  peas.  It  is  clearly  desirable  to  pick  the  sound  pods  as  soon 
