1912.] NATURAL SCIENCES OF PHILADELPHIA. 311 
other than Lepidoptera; but unless the birds recognized butterflies 
in general—a group which cannot be mistaken for other insects— 
as part of their natural prey, it is difficult to understand their eager 
excitement at the sight of those I offered them” (p. 811). 
Before quoting further, let us look into this argument a little: 
it is characteristic of the selectionist style. He is very charitable 
in admitting that predatory deftness may have been acquired in 
chasing other insects than butterflies. A little reflection will con- 
vince anyone, be he ignorant or not concerning the important con- 
stitutents of bird food, that butterflies even if eaten, can furnish 
but a small percentage of bird food, namely, an amount proportional 
to their numbers among diurnal insects as a whole. Hence a 
correspondingly small amount of training in predatory deftness can 
possibly have been acquired from capturing them. Pocock finds 
it difficult to understand the eager excitement of the birds at the sight 
of Lepidoptera, unless they recognized them as such; this after 
telling us on the preceding page of ‘the exceeding keenness of the 
birds for the insects brought to them. This was no doubt due in a 
measure to our inability in the Gardens to feed the birds on living 
insects other than mealworms.”’ 
Caged canaries, sometimes become frantically excited when a 
grasshopper or other insect is held up to the bars of their cage— 
they may never have seen an insect in their life before, they only 
know there is something they want. Pocock’s parenthetical expres- 
sion concerning Lepidoptera—‘“ a group which cannot be mistaken 
for other insects’’—directly opposes many arguments by selec- 
tionists relative to the resemblances of Sesiide to Hymenoptera; 
but any argument to establish the present point without reference 
to its bearing on other phases of the theory is a long-standing rule 
among selectionists. Continuing his argument, Pocock says: 
“Again, unless the species of butterflies used for the experiments are, 
or were in the past, habitually preyed upon by birds,®” whence comes 
the extraordinary skill the liberated specimens . . . . displayed in 
dodging the swoop of birds in midair? Having repeatedly seen the 
aim of the pursuing bird baffled by the evasive twist of the butterfly, 
I cannot doubt that the insect’s behavior was prompted by the 
instinct to escape an habitual enemy of its species, of the same class, 
and with the same predatory methods” (p. 811). 
% It is worth pointing out that the disciple is here arguing directly against 
one of the cardinal teachings of the master, as Poulton iterates and reiterates, 
“acceptance is not proof of palatability” (Trans. Ent. Soc. Lond., 1902, pp. 436, 
317, 348, and 389). 
