352  Nature  and  Structure  of  Cochineal.   {  A^ut°us[' Srm- 
article  by  Blanchard  20  already  referred  to.  In  this  connection  the 
article  on  "  The  Culture  of  Cochineal  in  India/'  by  Dr.  Roxburgh  8 
in  the  American  Journal  of  Pharmacy,  1842,  pp.  137-145,  may 
be  of  considerable  interest.  C.  J.  Sage  17  has  recently  published  a 
note  on  the  cultivation  of  cochineal  in  the  Canary  Islands,  from 
which  most  of  our  commercial  supplies  are  now  obtained.  Prob- 
ably the  most  complete  work  on  the  distribution  and  cultivation  of 
the  cochineal  insect  is  by  de  Ruuscher  which  was  translated  into 
German  by  Mylius  9  in  1751  and  is  included  in  his  work  entitled 
""Physikalische  Belustigungen."  In  speaking  of  the  culture  of 
cochineal  insects  he  says,  .all  that  is  necessary  is  for  one  to  raise 
small  nests  upon  potted  Nopal  plants  growing  in  the  house.  Then 
when  they  are  ready  to  propagate,  the  insects  are  transferred  to  the 
Nopal  plants  growing  in  the  fields.  In  a  few  days  the  female  lays 
her  eggs,  dying  shortly  thereafter.  The  young  develop  under  the 
mother  and  when  mature  they  creep  up  the  Nopal  stems  seeking 
always  the  juiciest  and  greenest  parts.  Recently  there  has  been 
published  by  Leon  Diquet  21an  article  on  "  The  History  of  The 
Cochineal  Insect  of  Mexico,"  and  which  contains  a  number  of  illus- 
trations of  the  Nopal  plantations  as  well  as  very  much  information 
concerning  the  cultivation  of  cochineal  in  that  country. 
Life  History  of  Cochineal  Insect. 
In  going  over  the  literature  we  find  more  or  less  fragmentary 
and  even  contradictory  accounts  of  the  life  history  of  the  cochineal 
insect.  The  development  should  be  further  studied  upon  living 
material.  The  following  facts  based  upon  an  examination  of  the 
literature  as  well  as  my  own  studies  of  the  dried  insect  may  be  of 
some  interest.  The  female  insect  is  without  wings,  about  2  mm.  in 
length  and  consists  of  from  9  to  12  segments.  It  is  somewhat 
globular,  becoming  later  distinctly  ovoid.  In  general  appearance, 
as  it  creeps  over  the  cactus  stems,  it  is  convex  on  the  upper,  that 
is  the  dorsal  surface,  and  somewhat  flattened  or  concave  below,  that 
is  on  the  ventral  surface.  It  is  covered  with  glaucous  dust  being  a 
coat  of  wax.  This  wax  is  a  protective  secretion  and  is  formed 
as  a  glandular  secretion  by  the  "wax  pores  "  (Fig.  1,  w)  and  wax 
hairs  (Figs.  5  and  6),  the  anatomy  of  which  has  been  worked  out 
by  Mayer.10  It  is  therefore  formed  very  differently  in  Coccus 
Cacti  from  the  other  members  of  the  Coccidece,  in  which  it  is  secreted 
