1912.] NATURAL SCIENCES OF PHILADELPHIA. 333 



by the United States Biological Survey because of a direct realization 

 from these trials of the futility of experiments 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 (Carabidse), 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. 



