222 ENTOMOLOGY 



cumstances. Thus, one gaudy caterpillar is refused by a cer- 

 tain bird, at once, or else after being tasted, but another and 

 equally showy caterpillar is eaten without hesitation. Or, an 

 insect at first rejected may at length be accepted under stress 

 of hunger; or a warningly colored form disregarded by some 

 animals is accepted by others. Moreover, some of the experi- 

 ments with captive insectivorous animals are open to objection 

 on the score of artificiality. 



Nevertheless, from the data now accumulated, there emerge 

 some conclusions of definite value. Frank Finn, whose con- 

 clusions are quoted beyond, has found in India that the con- 

 spicuous colors of some butterflies (Danaime, Acrcea viola, 

 Delias eucharis, Papilio aristolochice) are probably effective 

 as " warning " colors. Marshall found in South Africa that 

 mantids, which would devour most kinds of butterflies, includ- 

 ing warningly colored species, refused Acrcea, which appeared 

 to be not only distasteful but even unwholesome; Acrcca is 

 eaten, however, by the predaceous Asilidse, which feed indis- 

 criminately upon insects for example, beetles, dragon flies and 

 even stinging Hymenoptera. The masterly studies of Mar- 

 shall and Poulton strongly support the general theory of warn- 

 ing coloration. 



In this country, much important evidence upon the subject 

 'has been obtained by Dr. Judd from an extensive examination 

 of the stomach-contents of birds, supplemented by experiments 

 and field observations. Judd says that Murgantia histrionica 

 and other large showy bugs are usually avoided by birds ; that 

 the showy, ill-flavored Coccinellidas, and Chrysomelidse such 

 as the elm leaf beetle, Diabrotica, and Leptinotarsa (Dory- 

 phora), possess comparative immunity from birds; and that 

 Macrodactylus, Chauliognathus and Cyllene are highly exempt 

 from attack. Such cases, he adds, are comparatively few 

 among insects, however, and in general, warning colors are 

 effective against some enemies but ineffective against others. 



Generally speaking, hairs, stings and other protective de- 

 vices are accompanied by conspicuous colors though there 



