526 
EXAMINATION  OF  THE  CHRYSOMELA. 
lows,  and  thinks,  like  Liebig,  that  it  is  formed  from  the  salicine 
which  the  creatures  take  in  with  their  food. 
This  remarkable  phenomenon  has  induced  the  author  to  ex- 
amine another  species  of  the  same  genus,  namely,  the  Ghryso- 
mela  cenea  (Aini,  Oken),  which  lives  on  the  leaves  of  the  alder. 
He  found  that  these  animals  contain  all  the  materials  of  the 
leaves,  many  of  them  however  in  a  modified  form.  Of  the  tan- 
nin, which  gives  a  blue  color  with  iron,  and  which  the  leaves 
contain  in  abundance,  no  trace  was  to  be  found  in  the  beetles ; 
and  the  author  therefore  thinks  that  the  tannic  acid  is  decom- 
posed in  the  body  of  the  animal  into  sugar  and  gallic  acid.  But 
in  the  contents  of  the  digestive  organs,  both  in  the  larva  and 
the  beetle,  he  found  no  gallic  acid ;  but,  on  the  other  hand,  he 
states  that  he  detected  tannate  or  gallate  of  iron  in  the  skin  of 
the  larva  and  in  the  elytra  of  the  beetle  intimately  intermixed 
with  the  chitine,  from  which  he  supposes  that  their  dark  blue  me- 
tallic color  may  be  explained  by  the  presence  of  this  salt.  The 
constituents  enumerated  by  the  author,  calculated  for  100  parts 
of  the  living  beetles,  are  as  follows  : — 
1.  Water  (moisture)        .        .       .  706-0 
2.  Constituents  extracted  by  ether       .  86-0 
3.  Constituents  extracted  by  alcohol         .  46-0 
4.  Constituents  extracted  by  water         .  60-0 
5.  Constituents  extracted  by  muriatic  acid  32-0 
6.  Constituents  extracted  by  potash       .  32-0 
7.  Skeleton  (chitine)         ....  36*0 
The  extract  2,  consists  of  fatty  oil,  wax  and  chlorophyl,  with 
traces  of  essential  oil ;  3,  of  yellowish-brown  resin,  osmazome, 
malate  and  muriate  of  potash,  soda,  lime  and  sugar ;  4,  of  al- 
bumen, animal  extractive  matter,  sugar,  formiate,  malate,  phos- 
phate, muriate,  and  sulphate  of  potash,  soda,  ammonia,  lime  and 
magnesia  ;  5,  of  gallate  of  iron,  phosphate  of  lime,  magnesia  ; 
6,  of  humic  acid,  formed  from  animal  fibre  Chem.  Gaz.,  from 
Vierteljahrsehrift  fur  Prakt.  Pharm. 
