526     •  Making  Money  out  of  "  Bugs."     { Am^™si  Fig \T' 
When  used  against  moths : 
Naphthalene  is  very  effective  in  killing  adult  moths,  larvae 
and  eggs. 
Camphor  is  very  effective,  but  less  so  than  naphthalene. 
Cedar  chests  prove  to  have  power  to  kill  adult  moths  and 
young  larvae. 
Cedar  chips  give  some  protection,  but  are  not  entirely 
effective. 
Cedar  leaf  oil  is  very  effective. 
Pyrethrum  powder  is  100  per  cent,  effective  on  larvae  and  is 
an  excellent  protective. 
Kerosene  and  gasoline  are  effective,  gasoline,  in  particular, 
killing  the  eggs. 
Strong  soap  suds  will  kill  larvae  and  eggs  on  flannel. 
Sulphur,  when  burned,  is  partially  effective. 
Heat,  in  an  oven,  at  uo°  F.  for  31  minutes  is  effective. 
Hot  water  at  1400  F.  for  10  seconds  is  very  effective. 
Powdered  cloves  appear  to  have  considerable  value. 
Among  substances  generally  supposed  to  have  value,  but  proving 
ineffective  in  tests  are : 
Lavender  flowers,  though  the  oil  of  Lavender  flowers  has 
some  value  as  a  protective. 
Of  all  the  commonly  used  household  insecticides,  pyrethrum 
powder  has,  probably,  the  widest  range  of  effective  application.  It 
would  be  more  popular  than  it  is,  were  it  not  that  many  facts  re- 
garding its  use,  preparation  and  storage  are  not  well  understood. 
To  be  effective,  pyrethrum  must  be  in  a  very  fine  powder.  Con- 
trary to  general  belief,  it  acts  as  a  contact  poison  and  it  is  not  neces- 
sary for  it  to  be  eaten  by  the  insect.  Supposedly,  it  gets  into  the 
insect  system  through  minute  breathing  pores  along  the  sides  of  the 
body.  For  this  reason,  the  more  dust  made  in  the  air,  when  applying 
it,  the  better  the  result.  It  does  not  kill  the  insect  immediately,  but 
does  produce  a  sort  of  "paralysis  at  once.  Death  is  none  the  less  cer- 
tain, however.  Stems,  no  matter  how  finely  powdered,  are  worth- 
less. Flowers  collected  with  long  stems  are  sure  to  produce  a  very 
inferior  powder  if  the  stems  are  ground  with  them.  The  same  is 
true,  of  course,  if  stems  are  added  during  or  after  grinding. 
Pyrethrum,  in  powder  at  least,  does  not  retain  its  strength  in- 
definitely. Both  whole  flower  heads  and  powdered  have  been  found 
to  retain  their  activity  for  about  three  years.    Powdered  flowers 
