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. 



Included in the latter category are the bronzy wood- 

 borers (Buprestidse), among the most serious pests to 

 fruit and forest trees. The larva, known as flat- 

 headed borers, do the mischief, often killing trees by 

 fig. 22. — Pme completely girdling them just under the outer bark. 

 ( chaicophom The adults are incased in a glittering coat of hardest 

 virginiensis) . ma ji an( j although they expose themselves on flowers 



(Marx del. Bu- ' ,■•.,* i pi 



reau of Ento- and leaves or on the limbs of trees," they are not red 

 moiogy. 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- 

 cies are sometimes captured, one grosbeak having obtained the bulky 

 buprestid Chaicophom 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 (Dicer ca, 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 (Elateridse), the larva? 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 



