1912.) NATURAL SCIENCES OF PHILADELPHIA. . 333 
by the United States Biological Survey because of a direct realization 
from these trials of the futility of expermments as indications of the 
food preferences and, therefore, of the economic status of species 
under natural conditions. 
It is not the writer’s purpose to give a detailed account of these 
experiments, but merely lists of the items accepted and rejected, with 
‘comments thereon. It will be helpful to consider separately those 
items which were both refused and devoured. Several discrepancies 
exist between the statistics here presented and the published accounts 
previously referred to, but the writer has made the following tabula- 
tions directly from notebooks containing daily entries regarding 
the experiments. He believes these should be accepted as correct, 
rather than statements in the printed pages that have run the gantlet 
of editors and proof-readers, whose efforts often have just the oppo- 
site result, so far as accuracy is concerned, from that which the 
exercise of their true functions is intended to insure. 
To interpret the bearing of this and the following experiments on 
the theory of protective adaptations, it should be recalled that the 
common types of what is called warning coloration are the combina- 
tions of black with red, yellow, and white. Metallic colors also are 
usually classed as warning. Besides the insects, etc., possessing 
these colors, other groups, for various reasons, are said to be specially 
defended. Among these are ground beetles (Carabide), many of 
which have acid and nauseous secretions; the true bugs (Hemiptera), 
nearly all pungently flavored and malodorous; ants, and the stinging 
wasps and bees (Hymenoptera); the spiders and centipeds with 
poison fangs; and the millipeds with acid juices. All of these crea- 
tures are supposed to be especially protected from the attacks of 
predaceous animals or, in other words, to be distasteful. 
To bring out clearly the attitude of Judd’s captive birds toward 
these categories of ‘‘protected”’ animals, the writer has tabulated 
the results (as regards the animal food only) of each series (except 
the shorter ones) of experiments under the following headings: 
“warningly colored” species, others ‘‘specially defended,’ and 
“‘non-protected’”’ species. Of course, the term ‘‘non-protected”’ 
is not in accordance with the theories of protective adaptations, as 
the more obscurely colored and innoxious forms thus described are 
also said to be protected, but chiefly in a more passive way than the 
other two groups, namely, by concealing coloration. ‘‘Non-pro- 
tected”’ is therefore used to bring into greater contrast the theoretical 
attributes of these comparatively poorly ‘protected’ species. 
