4 Evolution and Adaptation 
is the means of securing the insects usec for food, it fulfils 
a purpose necessary for the welfare of she spider. 
The making of the nests by birds appears to be also in 
large part an instinctive act; although some writers are 
inclined to think that memory of the nest in which the 
young birds lived plays a part in their actions, and imitation 
of the old birds at the time of nest-building may, perhaps, 
also enter into the result. It has been stated that the first 
nest built by young birds is less perfect than that built by 
older birds, but this may be due to the bird’s learning some- 
thing themselves in building their nests, z.e. to the perfecting 
of the instinct in the individual that makes use of it. In any 
case much remains that must be purely instinctive. The 
construction of the comb by bees appears to be largely, per- 
haps entirely, an instinctive act. That this is the case was 
shown by isolating young workers as soon as they emerged 
from the cell, and before they could have had any experience 
in seeing comb built. When given some wax they set to 
work to make a comb, and made the characteristic six-sided 
structures like those made by the bees in a hive. The forma- 
tion of so remarkable a structure as the comb is worthy of 
admiration, for, with the greatest economy of material, a 
most perfect storeroom for the preservation of the honey is 
secured. This adaptation appears almost in the nature of 
foresight, for the store of honey is used not only to feed the 
young, but may be drawn on by the bees themselves in time 
of need. It is true that a comparison with other kinds of 
bees makes it probable that the comb was first’ made for the 
eggs and larve, and only later became used as a storehouse, 
but so far as its form is concerned there is the same economy 
of constructive materials in either case. 
The behavior of young birds, more especially those that 
take care of themselves from the moment they leave the egg, 
furnishes a number of cases of instincts that are protective. 
If, for example, a flock of young pheasants is suddenly dis- 
