ADAPTIVE COLORATION 183 



not only distasteful but even unwholesome; Acraa is eaten, however, 

 by the predaceous Asilidae, which feed indiscriminately upon insects 

 for example, beetles, dragon flies and even stinging Hymenoptera. The 

 masterly studies of Marshall and Poulton strongly support the general 

 theory of warning 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 Coccinellidae, and 

 Chrysomelidae such as the elm leaf beetle, Diabrotica, and Leptinotarsa 

 (Doryphora), 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 ene- 

 mies but ineffective against others. 



Generally speaking, hairs, stings and other protective devices are 

 accompanied by conspicuous colors though there are many exceptions 

 to this rule. These warning colors, however, fail to accomplish their 

 supposed purpose in the following instances, given by Judd. Taking in- 

 sects that are thought to be protected by an offensive odor or a dis- 

 agreeable taste: Heteroptera in general are eaten by all insectivorous 

 birds, the squash bug by hawks and the pentatomids by many birds; 

 among Carabidae with their irritating fluids, Harpalus caliginosus and 

 pennsylvanicus are food for the crow, catbird, robin and six others; 

 Carabus and Calosoma are relished by crows and blackbirds; Silphidae 

 are taken by the crow, loggerhead shrike and kingbird ; and Leptinotarsa 

 decemlineata is eaten by at least six kinds of birds: wood thrush, rose- 

 breasted grosbeak, quail, crow, cuckoo and catbird. Of hairy and spiny 

 caterpillars, Arctiidas are eaten by the robin, bluebird, catbird, cuckoo 

 and others; the larvae of the gypsy moth are food for the blue-jay, robin, 

 chickadee, Baltimore oriole and many others [thirty-one birds, in Massa- 

 chusetts]; and the spiny caterpillars of Vanessa antiopa are taken by 

 cuckoos and orioles. Of stinging Hymenoptera, bumble bees are eaten 

 by the bluebird, blue-jay and two flycatchers; the honey bee, by the 

 wood pewee, phoebe, olive-sided flycatcher and kingbird; Andrena by 

 many birds, and Vespa and Polistes by the red-bellied woodpecker, king- 

 bird, and yellow-bellied flycatcher. 



These facts by no means invalidate the general theory, but they do 

 show that "disagreeable" qualities and their associated color signals 



