474 THE AMERICAN NATURALIST.  [VOL. XXXIII 
seems low in cases where, as in the flicker, we find stomachs 
containing 3000 ants. The stingless ants pretend to sting, 
but there are many birds that they do not deceive. 
There are two records of the caterpillar of the Io moth having 
been eaten by the yellow-billed cuckoo. In one instance no 
less than seven of these large stinging larve were taken from 
a single stomach. 
It is plain that from my facts I interpret, not cases of pro- 
tection and non-protection, but cases of greater and lesser 
efficiency of protective devices. 
Ill-Flavored or with Irritating Qualities. 
In the Heteroptera, particularly in the Pentatomidz, we have 
insects emitting vile stenches. In speaking of the Pentato- 
midz Comstock says: “ It should not be concluded, however, 
that only members of this family possess this disagreeable 
odor; for most of the Heteroptera protect themselves by ren- 
dering their bodies unpalatable in this way. Doubtless birds 
soon learn this fact and leave such bugs alone.” An English 
sparrow raised from the nest refused a Brochymena, and a song 
sparrow did not eat one of these insects, but ate with relish 
Lygus and small stinking Reduviids. In the examination of 
song-sparrows’ stomachs I often find remains of Pentatomids, 
and I know of no insectivorous bird that does not eat Hete- 
roptera. Catbirds and thrashers (caged) relish Brochymena. 
Blackbirds and crows frequently contain from four to ten 
Euschistus. The stench may protect bugs from some birds, 
but it certainly does not secure complete immunity from but 
very few birds of eastern United States. The lace-wing fly is 
about as nauseating an insect as I know of; yet it was greedily 
devoured by a caged song sparrow, and has been taken from 
the stomach of a great-crested flycatcher. Phalangidz have 
a sickening stench, but they are eaten by many birds, particu- 
larly by house wrens and cuckoos. Millipedes come in the 
same category and are relished by birds. 
In coming to the protective adaptations of Coleoptera we find 
a greater efficiency of the actual working of protective devices, 
