362  Nature  and  Structure  of  Cochineal.  {K\^J^T' 
all  the  varieties  in  commerce  may  not  give  the  same  results.  Atten- 
tion should  be  directed  to  the  fact  that  the  cochineal  of  commerce 
may  contain  extraneous  inorganic  substances.  One  will  also  find 
short  isolated  pieces  of  the  spines,  and  fragments  of  the  stems 
of  the  cacti  attached  to  the  mother  insect. 
These  studies  show  that  cochineal  is  the  dried  remains  of  the 
female  insect  Coccus  Cacti  (Fam.  Coccidce)  enclosing  her  young 
larvae.  When  properly  cleared,  the  mother  insect  is  more  or  less 
ovoid  or  plano-convex  and  for  the  most  part  nearly  transparent 
and  within  her  body  are  from  about  20  to  40  larvae  in  different 
stages  of  development  (Fig.  1).  The  larvae  each  have  a  charac- 
teristic beak  or  rostrum  in  the  nature  of  two  spiral  dense  coils  and 
when  mature  the  2  antennae  and  3  pairs  of  legs  are  seen  protruding. 
I  acknowledge  the  services  of  Philip  F.  Fackenthall  for  assist- 
ance in  the  experimental  part  of  this  paper. 
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