44 FOOD HABITS OF THE GROSBEAKS. 
for any injury done in this way by feeding upon the prey of these 
beetles—the scale insects. 
Fireflies, which are predaceous both in the larval and adult stage, 
are constantly fed upon by grosbeaks. These insects are supposed to 
be excellent examples of protected species, having the power of secret- 
ing nauseous juices, while the “ fire” is supposed to act as a warning 
signal and certify the bearer’s identity to its enemies. It is said that 
some birds refuse them. However, since 28 rose-breasted grosbeaks 
fed upon them and 6 to 12 of the beetles were found in single stom- 
achs, they must be relished by this species at least. Fireflies prey 
upon many important agricultural pests; hence the destruction of 
any considerable number of them is a loss; and while but 2.71 per- 
cent of the grosbeak’s food consists of these useful beetles, the bird is 
chargeable with a distinctively injurious habit. 
Thus far only a fourth of the rosebreast’s animal food has been 
discussed. Less than half this amount, or only about a tenth of the 
total animal matter, is made up of beneficial insects whose destruc- 
tion is a loss to man. The remaining nine-tenths con- 
sists in part of insects of neutral import, but mostly 
of positively injurious species. 
Tncluded in the latter category are the bronzy wood- 
borers (Buprestide), among the most serious pests to 
fruit and forest trees. The larvee, known as_ flat- 
headed borers, do the mischief, often killing trees by 
se ae completely girdling them just under the outer bark. 
(Chalcophora The adults are incased in a glittering coat of hardest 
virginiensis). mail, and although they expose themselves on flowers 
(Marx del. Bu- é 
reau of Ento- and leaves or on the limbs of trees, they are not fed 
mology. upon to a marked degree by most birds. The rose- 
breasted grosbeak, however, seems to relish them, 3.02 percent of its 
food being composed of these well-protected beetles. The larger spe- 
cles are sometimes captured, one grosbeak having obtained the bulky 
buprestid Chalcophora virginiensis (fig. 22), which is very destruc- 
tive to pines. This species is an inch in length and as firm and hard 
as a nut. Smaller species of another genus (Déicerca, including D. 
obscura), which feed on hickory and other deciduous trees, also are 
devoured. Many others not identified were eaten by the 26 grosbeaks 
which secured buprestids, and the rosebreast must be characterized 
as one of the important enemies of these beetles. 
Resembling the buprestids in compact build and equaling them 
in evil qualities are the click-beetles (Elaterids), the larvae of which 
are commonly known as wireworms. Their attacks on meadow- 
grass, grains, and strawberries are of annual occurrence, and result 
in much damage. Twenty-three grosbeaks, or about one-seventh of 
