1912.] NATURAL SCIENCES OF PHILADELPHIA. 283 



distastefulness of certain insects and the palatability of others 

 consists of the results of experiments. The cry always is to test 

 theories under experimental conditions, but there are many things 

 which cannot be so tested. The very conditions of captivity and 

 the limited choice of food constitute abnormalities which cannot 

 fail to distort the food relations of most animals, and so modify the 

 results of experiments that they bear little or no analogy to natural 

 conditions. 



In experiments play is allowed to the fancy of the experimenter, 

 and the interpretation of facial and other expression of the subject 

 has often been given more weight than the actual result of the 

 experiment, that is, whether the insect was eaten or rejected. R. I. 

 Pocock 5 very frankly admits this, saying, "It is quite clear that the 

 plain record of an insect being eaten is no proof of its palatability. 

 Better evidence on this head is supplied by the behavior of the bird 

 towards it. After a little experience in the matter, I was able to 

 satisfy myself, at all events, as to the approximate correctness of my 

 interpretation of the bird's actions, and to judge thereby of the 

 comparative palatability of the insects they tasted." This is honest 

 confession at any rate, but the writer must take issue with this 

 author as to the value of interpretation of behavior. "The plain 

 record of an insect being eaten," which he holds up to scorn, may not 

 show palatability, but shows something much more definite, namely, 

 that the insect is acceptable food. Palatability in the sense used 

 by some of the experimenters is entirely a figment of the imagination. 

 This is proved by the -many cases of refusal in captivity of insects 

 which are eaten under natural conditions, and by the misinterpreta- 

 tion of the following among other features of the behavior of caged 

 birds and other animals. 



Wiping the bill or mouth: If a bird wipes its bill, or a lizard or 

 frog its mouth, when it is being experimented with, the action is 

 almost always credited as a sign of distaste. Yet nothing is more 

 common than to see wild birds wiping their beaks across branches or 

 other objects. It occurs at all times, apparently is often done in a 

 purely mechanical way, and certainly has no essential connection 

 with the taking of food or perception of tastes. 



Dropping and picking up or in any way manipulating the prey 

 is another thing usually taken as evidence of unpalatability, but 

 nothing could be more at variance with conclusions drawn from 



5 Proc. Zool. Soc. Lond., 1911, p. 810. 



