Aug.  1,  1895.]  Supplement  to  the  “ Tropical  Agriculturist.'” 
abdomen.  Tlie  blunt,  four-corned,  usually  varie- 
gated i)U[)iC  hang  on  leaves.  The  fully-developed 
larvic  are  longer  than  the  beetles  ; they  closely 
resemble  those  of  the  leaf  beetles,  but  are  not  so 
thick-set,  and  their  longer  legs  stick  out  more 
laterally.  They  are  covered  with  warts  and  little 
spine.s.  The  larvae  and  beetles  of  most  species 
feed  chiefly  on  aphides  and  shield-lice  ; they  are 
therefore  useful.  The  yellow  eggs  are  laid  in 
heaps. 
We  have  lately  heard  a good  deal  in  Ceylon 
about  Mr.  Koebele  and  his  Australian  hvly-birds, 
in  connection  with  the  visit  of  that  gentleman  to 
the  Island.  Through  his  agency  the  white  .scale 
( Icerya  Purchasi)  which  did  such  damage  to  the 
apple  orchards  of  California  has  been  entirely 
eradicated  by  means  of  the  lady-bird,  Vedalia 
cardinalis.  Professor  Cook  of  the  California  Uni- 
versity, an  entomologist  of  repute,  has  lately 
published  a report  of  his  ob.servations  with  re- 
ference to  the  work  of  the  Rhizobiids — another 
species  of  lady-bird  introduced  by  Mr.  Koebele  into 
California.  The  most  troublesome  pest  in  connec- 
tion with  orange  and  lemon  culture  is  the  black 
scale,  scientifically  known  as  Lecanium  Ol&ti,  but 
it  is  now  authentically  announced  that  this  pest 
can  be  got  rid  of  through  the  agency  of  llhizobiids 
— the  three  important  species  being  Ithizobius  too- 
woomb(c,  described  ns  a small  black  beetle  with  a 
brown  head  and  thorax  ; H.  debilis,  which  is  about 
the  same  size  as  the  other  but  is  entirely  black 
above  and  below,  and  R.  ventralis,  which  is  larger, 
entirely  black  above,  with  short  light  hairs  and 
brown  below.  A single  pair  of  Rhizobiids,  ac- 
cording to  Albert  Koebele’s  estimate,  could  produce 
15,000,000,000  in  a single  year,  and  Professor  Cook 
considers  this,  from  his  observations,  to  be  a 
re.isouable  estimate.  Details  of  the  wonderful 
effect  of  the  lady-birds  in  clearing  orange,  lemon, 
and  olive  orchards  are  given  bj”^  Professor  Cook, 
who  says  : I have  been  a hard  student  of  entomo- 
logy for  thirty  years,  and  I am  free  to  say  that  it 
is  the  wise  and  certain  policy  for  this  great  fruit 
state  to  keep  Mr.  Koebele  iu  Australia  for  some 
years  hiiating  and  shipping  to  us  more  of  these 
natural  aids  in  fighting  our  insect  foes. 
The  Pacific  Rural  Pre.ss  likewise  express  its 
views  in  enthu-siastic  terms  on  this  matter,  thus  : 
“ The  triumph  of  the  Vedalia  over  the  cottony 
cushion  scale  has  been  counted  the  most  sweeping 
victory  for  entomological  science,  but  it  is  now 
a question  whether  the  rout  of  the  black  scale  by 
the  Rhizobiids  will  not  indeed  prove  a greater 
victory  because  the  area  invaded  by  the  black 
scales  is  wider Now  there  seems  to 
be  demonstration  which  cannot  be  controverted, 
and  Mr.  Koebele’s  later  achievements  in  tlie 
gathering  and  shipment  of  these  friendly  in.sects 
to  California  may  beat  his  record  on  the  Vedalia. 
The  two  pests  about  which  at  present  the 
planting  community  in  Ceylon  are  exercised 
in  mind  are  the  green  coffee  bug,  Lecanium  oiridc 
and  Orthezia  nacrea,  a comparatively  new  pest, 
which,  however,  it  is  apprehended,  will  do  much 
damage  to  ten.  In  a communication  to  the 
Tropical  Agriculturist  for  June  last  Mr.  E.  E. 
Green,  our  local  entomologist,  states  that  he  is 
daily  expecting  a consignment  of  lady-birds  from 
California  to  experiment  with  on  the  above-men- 
tioned ])ests,  mentioning  that  the  two  species 
indented  for  are  Nuvius  Koebelii  and  Vedalia  cardi- 
mlis.  Whether  the  beetles  have  arrived  yet  and 
what  results  have  followed  so  far,  we  are  not 
aware.  Seeing  the  success  with  the  Riiizobiids  on 
Lecanium  oleoi  it  i.s  a pit  y that  some  of  the  latter 
were  not  imported  for  trial  upon  the  local  specias 
of  Lecanium — the  green  colfee  bug,  but  no  doubt 
^Ir.  Green  luis  been  well  advised,  and  we  await 
th  ) result  of  trials  with  much  interest. 
[Since  the  above  was  written  we  have  heard  with 
regret  that  the  lady-birds  consigned  from  Cali- 
fornia were  all  found  to  be  dead  on  reachint? 
Ceylon. — Ed.  A.yi.'] 
THE  VALUE  OF  KAINIT. 
The  best  known  and  most  used  of  potash 
manures  is  Kamit,  a mineral  deposit  occurring  in 
Germany,  and  conisistiug  chie%  of  chloride  of 
potassium,  sulphate,  of  magnesia,  and  water,  with 
usually  chlorides  of  ra  iguesium  and  sodium.  An 
average  sample  should  contain  about  ISA  per  cent 
of  potash. 
Dr.  Pream  referring  to  the  value  of  potash  says 
that  light  soils  generally  yield  better  crops  after 
treatment  with  potash  salts,  and  also  recommends 
it  for  vegetable  soils.  A paper  by  Dr.  Marloth 
which  appears  in  the  Cape  Journal  of  Agriculture 
gives  interesting  details  of  experiments  which 
go  to  show  the  importance  of  mineral  fertilizers, 
and  particularly  of  potash.  Referring  to  kainit 
he  says  : “ Kainit,  one  of  the  most  excellent  crude 
potash  salts,  is  rich  in  magnesia  compounds,  which 
by  their  water-absorbing  properties  have  a marked 
effect  in  making  and  keeping  the  soil  compact 
and  moist.  It  is  thus  e.xactly  what  is  needed  by 
light  sandy  soils.”  The  writer  then  goes 
oil  to  state  that  on  ascertaining  by  analyses  the 
relative  proportions  of  the  principal  food  ingredi- 
ents removed  from  the  soil  by  the  commoner 
crops,  it  will  be  found  that  there  is  always  much 
more  potash  removed  than  phosphoric  acid,  wdiile 
all  natural  fertilizers  as  well  as  most  artificial 
mixtures  contain  comparatively  little  or  almost 
nothing  of  potash.  To  this  then  is  attributed  the 
fact  that  soil  cultivated  for  a long  time  by  means 
of  natural  or  artificial  manures,  without  the 
additional  application  of  potash,  do  not  give 
I'esults  that  are  expected  of  them.  Many  soils 
again  are  naturally  deficient  iu  potash  and  need 
special  applications  of  potash  manures  to  improve 
them.  “ It  is  to  be  specially  noted,”  says  Dr. 
Marloth,  “ that  the  potash  supply  derivable  from 
ashes  is  exceedingly  small,  limited,  and  the  quality 
so  variable,  that  purchase  is  only  advisable  if  the 
strength  is  guaranteed  by  chemical  analysis.” 
This  writer  then  goes  on  to  give  details  of  experi- 
ments which  would  appear  to  conclusively  prove 
that  special  applications  of  potash  salts,  preferably 
in  the  form  of  kainit,  are  necessary  for  the  pro- 
duction of  large,  heallliy  and  early  crops.  Kainit 
is  also  believed  to  lie  injurious  to  all  ground-pests 
(including  the  irrepressible  white-ant),  and,  if  this 
can  be  conclusively  proved,  it  will  greatly  en- 
hance its  usefulness  in  the  tropics. 
Kainit  guaranteed  to.contain  12  percent  potash, 
IS  obtainable  for  about  .L2  per  ton  in  England. 
IVe  should  be  glad  to  .see  trials  made  with  this 
and  another  cheap  and  useful  fertilizer  (Basic 
einder)  iu  the  colony. 
