360 
Nature  and  Structure  of  Cochineal. 
Am.  Jour.  Pharm. 
August,  1913. 
gives  a  very  slight  effervescence  with  hydrochloric  acid.  The  ash 
of  cochineal  has  been  reported  to  consist  of  oxides  of  aluminium, 
calcium,  magnesium,  sodium,  potassium,  iron,  tin,  and  phosphorus, 
but  which  of  these  elements  are  naturally  in  the  insect  and  which 
are  added  has  not  been  determined.    When  these  facts  are  known 
Fig.  6. 
be* 
Microphotograph  of  mature  larva  in  cochineal  insect  of  commerce  showing  the  beak  or 
proboscis  extended  and  ready  for  penetrating  the  tissues  of  the  cactus;  a,  antennas;  /,  feet;  and 
h,  wax-hairs  covering  the  body. 
a  qualitative  test  for  the  elements  in  the  adulterant  would  be  suffi- 
cient to  exclude  inferior  grades. 
Gierke  13  calls  attention  to  the  fact  that  there  is  considerable 
difference  in  the  quality  of  the  commercial  article,  depending  upon 
the  locality  in  which  the  insects  are  cultivated,  which  crop  of  the 
season  is  harvested  and  the  manner  in  which  the  insects  are  killed. 
The  most  valuable  variety  is  known  as  "  Madres  "  and  repre- 
sents the  first  brood  of  the  season.  This  corresponds  to  the  variety 
formerly  known  as  "  Zacatillo/'  which  was  exported  from  Mexico. 
