1912.] NATURAL SCIENCES OF PHILADELPHIA. 313 
man has fired his last shot ineffectually at a charging tiger or rhinoce- 
ros; he naturally shows a ‘‘marked reaction”’ by taking to his heels, 
not because he or his ancestors have had similar experiences, but 
because he can run. So with the butterflies, skilful efforts to escape 
do not necessarily indicate previous racial experience of the same 
nature. 
The principal failing of the selectionists always has been a vast 
ignorance of what wild birds really eat. They have made very 
little effort to acquire such knowledge, and their speculations through- 
out show the lack of it. Practically the only large body of authentic 
information on the natural food habits of birds is contained in the 
records of the United States Biological Survey. They comprise 
detailed identifications of the contents of more than 48,000 bird 
stomachs representing all families of birds and collected in hundreds 
of localities in the United States at all seasons. The United States 
has a goodly representation of butterflies, yet only five of these 
48,000 stomachs contained remains of Rhopalocera. It is hoped 
this will be more satisfactory to the selectionists than the “negative 
evidence” they are accustomed to cite with contempt. 
The extreme artificiality of Pocock’s experiments and the inappli- 
cability of the results to the natural relations of British birds and 
insects are so evident that it is not worth while to comment on the 
details. A few comparisons of the results with those of experiments 
recorded by Poulton are of interest as showing the inconsistency, 
inter se, of experiments. It has not been possible to collect a large 
number of such comparisons because Poulton’s experiments were 
chiefly with lizards and few with birds, while the opposite is true of 
Pocock’s. The varying stages in which the insects were presented 
also tend to limit comparisons. The table includes all possible 
direct comparisons and only one pair in eight shows real correlation. 
Brrps: Poulton. Pocock. 
Vanessa urticw, Larva ccc eee DB) AT7TR4D1 
a 88° PUPA eae ; R A2R2D1 
Clisiocampa neustria, larva... 2 = SD Al 
Euchelia jacobe, ad... Jiganeancvntniea shee (AL AILR4 
Cosmotricha potatoria, Jarva... D A1R4D1 
Anthrocera filipendula, ad........ . . ; A R4 
LIZARDS: 
“Apis mellifera, worker... © 2. A R3 
Pieris rape, WC. eccccccccsccsecscsscnecesees ee A 20 A2 
Notes on Pocock’s experiments, by Prof. E. B. Poulton, are given 
