o<  MONTHLY. 
/V« 
Vol.  XVI.]  COLOMBO,  JANUARY  ist,  1897,  [No.  7. 
[THE  RIGHT  OF  REPRODUCTION  OF  THIS 
IMPORTANT  SERIES  OF  ARTICLES 
HAS  BEEN  SPECIALLY  SECURED 
FOR  THE  TROPICAL  AGRICUL- 
TURIST FROM  THE  AGENTS 
OF  MISS  ORMEROD.— Ed.  T.yl.] 
[All  Rights  Reserved.] 
Agricultural  Pests: 
WITH  METHODS  OF  PREVENTION, 
BY 
MISS  E.  A.  ORMEROI), 
(Laic  CunsuUincj  Entomologist  to  the  Royal  Agricultural 
Society  of  England) 
I. 
Insects  Injurious  to  General  Crops. 
HE  order  Dipt  era  includes  the 
Gnats  and  Corn  Midges,  also 
the  Daddy  Longlegs,  of  which 
the  grubs  are  so  hurtful  to 
many  kinds  of  crops ; the 
Blowflies,  which  cause  great 
waste  to  meat  in  summer ; 
the  Gadflies,  and  a very  large 
number  of  other  kinds,  which,  by  means  of  their  mag- 
gots, do  boundless  damage  year  by  year  to  the  roots  of 
cabbage,  onions,  and  other  garden-crops,  and  likewise 
to  the  heart  or  stem  of  the  growing  corn,  &c.  All 
flies  of  this  order  have  only  one  pair  of  wings  ; occa- 
sionally they  are  wingless.  The  hinder  pair  of  wings 
is  represented  by  a pair  of  appendages,  often  like  a 
slender  pin  with  a small  head ; these  are  known  as 
“ poisers  ’’  (scientiflcally,  haltcres),  because  they 
help,  or  aiipear  to  help,  to  poise  or  balance  the 
insect.  Some  of  these  insects  feed  by  suction,  as 
in  the  cise  of  the  gnats,  to  our  great  annoyance. 
The  maggots,  or  larva),  are  fleshy  ahd  (with  few 
e.vceptions)  footless ; sometimes,  like  the  Daddy 
Longlegs  grub,  they  have  a hard  head,  furnished  with 
uppers,  or  jaws;  sometimes  they  have  a soft  mass 
which  answers  for  a head,  commonly  bearing  a 
pair  of  hooks  instead  of  jaws,  with  which  they 
clear  out  the  substance  between  the  two  sides  of  a 
turnip-leaf,  or  from  the  inside  of  an  onion-bulb,  or 
other  soft  material  in  which  they  may  be  feeding] 
The  pupa-case,  or  chrysalis,  varies  in  shape ; in  soma 
kinds,  as  of  the  Gnat  and  Daddy  Longlegs,  for 
instance,  it  is  in  shape  much  like  the  creature  within, 
with  its  limbs  folded ; in  many  other  kinds,  as  the 
Onion  Fly,  Carrot  Fly  and  others,  the  pupa-case 
consists  of  the  hardened  maggot-skin,  which  shelters 
the  forming  fly  within. 
The  Daddy  Longlegs,  or  Cranefly,  likes  damp 
surroundings,  and  thus  we  get  an  idea  of  how  to 
keep  its  numbers  in  check.  The  flies  frequent  damp 
overshadowed  herbage,  or  marsh-land,  or  wet,  ne- 
glected weed-growths,  and  in  such  places,  they  lay 
their  eggs.  The  grubs  thrive  in  such  positions  or 
at  the  roots  of  crops  so  long  as  the  ground  is  not 
too  dry  for  them,  and  when  they  have  fed  for  some 
months  they  turn  into  a pupa,  which,  by  means  of 
the  spikes  at  its  side,  sets  itself  up  in  the  ground 
conveniently  for  the  fly  to  come  out  from. 
The  best  way  to  forestall  attack  is  to  make  the 
land  unsuitable  for  egg-laying.  Draining  marsh-land, 
and  rough  mowing  long  grass  or'Jneglected  herbage 
in  shady  parts  of  pasture-fields  hedge-sides,  and  other 
like  places,  drives  off  a great  deal  of  attack  ; but 
the  cliief  difficulty  is  on  land  broken  up  from  pas- 
ture or  clover-ley.  The  eggs  are  mostly  laid,  to- 
wards autumn,  in  such  localities  (that  is,  pasture 
fiilds  or  clover-ley);  therefore,  if  these  are  merely 
broken  up,  without  any  measures  having  been  pre- 
viously taken  to  prevent  egg-laying,  or  to  kill  the 
“ leather-jacket  ” grubs  in  them,  it  is  no  wonder  that 
the  next  crop  should  often  be  totally  devoured.  Any 
measures  that  will  serve  cither  of  those  purposeo 
are  highly  desirable.  Where  pastures  are  to 
be  broken  up,  it  is  a good  plan  to  fold  sheep  on 
the  ground  and  hand-feed  them,  thus  making  the 
ground  obnoxious  to  the  Cranefly  for  egg-laying,  and 
also  by  the  trampling  and  by  soddening  the  ground 
with  the  droppings  of  the  animals,  destroying  mo.st 
of  the  eggs  or  young  grubs  that  may  chance  to  be 
on  the  surface.  Heavy  dressings  of  hot  lime  are 
useful,  and  dressings  of  fresh  gas-lims,  or  alkali 
waste,  which  kill  everything  they  touch  whilst  in 
their  caustic  state,  are  an  excellent  preservative 
from  attack.  These  two  chemical  dressings  cost  little 
(where  they  are  procurable  at  all),  and  gradually 
