ADAPTIVE COLORATION 223 
are many exceptions to this rule. These warning colors, how- 
ever, fail to accomplish their supposed purpose in the follow- 
ing instances, given by Judd. Taking insects that are thought 
to be protected by an offensive odor or a disagreeable taste: 
Heteroptera in general are eaten by all insectivorous birds, the 
squash bug by hawks and the pentatomids by many birds; 
among Carabide with their irritating fluids, Harpalus caligi- 
nosus and pennsylvanicus are food for the crow, catbird, robin 
and six others; Carabus and Calosoma are relished by crows 
and blackbirds; Silphidze 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 gros- 
beak, quail, crow, cuckoo and catbird. Of hairy and spiny cat- 
erpillars, Arctiidze are eaten by the robin, bluebird, catbird, 
cuckoo and others; the larvee of the gypsy moth are food for 
the blue-jay, robin, chickadee, Baltimore oriole and many 
others [thirty-one birds, in Massachusetts]; and the spiny 
caterpillars of Vanessa antiopa are taken by cuckoos and ori- 
oles. Of stinging Hymenoptera, bumble bees are eaten by the 
bluebird, blue-jay and two flycatchers; the honey bee, by the 
wood pewee, pheebe, olive-sided flycatcher and kingbird; 
Andrena by many birds, and Vespa and Polistes by the red- 
bellied woodpecker, kingbird, and yellow-bellied flycatcher. 
These facts by no means invalidate the general theory, but 
they do show that ‘ disagreeable’ qualities and their associ- 
ated color signals are of little or no avail against some enemies. 
The weight of evidence favors the theory of warning colora- 
tion in a qualified form. While conspicuous colors do not 
always exempt their owners from destruction, they frequently 
do so, by advertising disagreeable attributes of one sort or 
another. 
The evolution of warning coloration is explained by natural 
selection; in fact, we have no other theory to account for it. 
The colors themselves, however, must have been present before 
natural selection could begin to operate; their origin is a ques- 
tion quite distinct from that of their subsequent preservation. 
