104 CONTROLLED NATURAL SELECTION 
To this must be added the sacrificing and 
combative instincts which are used by the 
parents for the protection of the young, and 
by the male for the protection of the female. 
Female protection by this method is not very 
common in Nature; the best examples are to 
be found in the higher animals, and especi- 
ally those which live together in societies : 
herds are often thus protected by the males. 
All possible combinations, of attracting and 
protecting colorations, will now be briefly 
considered. 
C=conspicuous or attracting coloration. 
J = inconspicuous or cryptically coloured, 
P= parents. 
Y=young. 
PC Very common, especially in species 
Y I which form themselves in societies of 
families ; but also rarely in other species 
in which the parents do not look after 
the young. To protect the more valu- 
able young, in the latter case, in the 
absence of the formation of a society. 
Pd Almost unknown, and forming ex- 
YC ceptions to the rule. Examples can 
often be explained; for instance, the 
young frog, the tadpole, when black 
and conspicuous, is not palatable. 
