basswood, preferably in moist, rotting logs. The larvae resemble those of Chal- 
cophora virginiensis except that they are longer, and the dorsal thoracic plate is 
marked with a V or U instead of a Y. This species often attacks at ax blazes and 
wounds and frequently riddles the wood beneath with its tunnels. 
The genus Dicerca contains many species that breed in dead and dying trees and 
logs. The adults are dark-gray to brown, medium-size, metallic beetles. The head is 
flat, the pronotum is wider than long and grooved or ridged down the middle, the 
scutellum is very small, the hind coxae are strongly dilated, and the elytra are 
extended into taillike appendages (9/5). A few of the more common eastern species 
and some of their hosts are as follows: D. divaricata (Say), the divergent beech 
beetle— various dead, dying, or injured hardwoods; D. obscura (F.)—reared from 
persimmon and sumac, collected on oak and hickory; D. punctulata (Sch6nherr)— 
various pines (often common around sawmills); D. /urida (F.)—hickory, American 
hornbeam, basswood, willow, and alder; D. tenebrosa (Kirby), the gloomy 
borer—pines and spruce; and D. tenebrica (Kirby)—poplar. 
The genus Melanophila consists of small- to medium-size beetles, the larvae of 
which bore in the inner bark and outer wood of their hosts. The majority of species 
attack very slow-growing, dying, or recently felled trees and are of no economic 
importance. In the West, certain species are strongly attracted to fires and are 
known as “fire bugs.”’ A key to the North American species has been published 
(1092). 
The hemlock borer, M. fulvoguttata (Harris), occurs throughout the Eastern 
United States and eastern Canada. Hemlock appears to be the preferred host, but it 
also occasionally attacks several other conifers such as eastern white pine, larch, 
balsam fir, and red, white, and black spruces. The adult is black with a metallic 
sheen and about 10 mm long. Each elytron usually bears three orange or yellow 
spots of equal size. 
Adults appear from late spring to late summer and deposit their eggs in groups 
deep in bark crevices on weakened, dead, and dying trees or on logs and wind- 
thrown trees in which the cambium is still moist. The larvae bore into the inner 
phloem and, if conditions are not favorable for their development, they remain there 
until they die. Under more favorable growth conditions they penetrate to the 
cambium region and construct tortuous, frass-filled galleries (fig. 123). Before 
becoming full grown, they construct cells in the outer bark in which they spend the 
winter. The life cycle may be completed in | year in dead trees and logs. In living 
trees, several years may be required. 
Management practices designed to promote rapid growth and good health of 
hemlock trees should be helpful in preventing damage by the hemlock borer. A 
study indicates that hemlock borer attacks are not successful until 60 percent of the 
roots are dead (9/6). Rapid salvage or cutting heavily infested trees is helpful in 
preventing population buildup in stands weakened by windthrow or defoliation 
(764). 
Several other species of Melanophila also occur in eastern forests. A few 
common ones and their hosts are as follows: The flatheaded fir borer, M. 
drummondi (Kirby)—fir, larch, spruce, and hemlock; M. notata (Castelnau)— 
pines; M. acuminata (De Geer)—spruce, fir, pine, and northern white-cedar 
(adults are common around forest fires and scorched timber); and M. aeneola 
Melsheimer—pines. 
The genus Brachys contains many species of leafminers. The larvae differ from 
the larvae of wood- or bark-boring species in having the prothorax only slightly 
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