Ornithological Observations and Reflections in Shetland. 365 
times—or. perhaps. three hundred. Facts at any rate are 
required as a basis of deduction. The relations of these young 
Kittiwakes and grown Herring: Gulls present some facts which 
seem significant. Here we have a certain resemblance in 
coloration. and marking, not indeed of one to the other, as thus 
differentiated in age, but of the two species when: mature. 
The young Kittiwake however is as familiar with its parents’ 
plumage as its own, ‘and as the parent is many times larger 
than the chick in the nest, it grows up accustomed to see 
something of a certain. appearance, very, much larger than 
itself, by whom it is fed and in whom it has the greatest con- 
fidence. Moreover, it, would. often. see—and still more often 
after it had left the nest—the Herring, Gull itself, so that, so 
Yong as nothing occurred to make it distrustful of: the latter, it 
would not have the shghtest reason to be alarmed by its quite 
close presence. As soon, however, as these attacks began to 
be made upon it, this reason would exist, and in proportion as 
they became more frequent, its apprehensive’ wariness and 
power of discrimination between the real and apparent parent 
or parental stock, would become sharpened. Just in the same 
proportion however, should the taste for young Kittiwakes 
become more strongly developed in the kindred species, would 
the process of assimilation in size and colouration of the latter 
to the former tend to increase, and thus, through a channel 
that one could never have predicted, a foundation would have 
been established for one of those mimetic resemblances of 
which nature presents us with such extraordinary examples. 
At least, if any advantage were to be derived through this 
diet—and it. should certainly be a nourishing one—such a 
result would be likely to follow. Whether it is actually now 
in process of manufacture, so to speak, I have not had sufficient 
opportunity of observation. to allow me to conjecture. It 
may very well be that we see as yet only the pedestal and 
not even the toe of the statue that may some day be standing 
on it. But, after all, even that is something. Is there any 
case analogous to this, as imagined, in the insect world ? 
Hornets prey largely and habitually on wasps, yet the latter 
do not appear to recognise them as enemies or make any 
particular effort to get out of their way. Yet caterpillars 
endeavour to escape the attack of the particular kind of 
Ichnemion fly parasitic upon them, and the larva of the 
Puss Moth has even special filaments from which it ejects over 
the enemy an acid which is sufficiently strong to be sometimes 
fatal. Bees, too, know and fear the Death’s Head Moth, and 
insects of all kind do what they can to get clear of the armies 
of foraging ants that devastate the forests of equatorial Africa 
and South America. Why then does not the common Wasp 
fly in terror from the Hornet ? Despite of what seem to our 
1916 Noy, 1. 

