INSECT ENEMIES OF EASTERN FORESTS 237 
These borers are not destructive to the trees, as they attack only those 
that are dying or dead and mine only in the bark, but they are so 
often met with in connection with injurious forms that they are worth 
noting. During extensive outbreaks of Dendroctonus beetles these 
larvae also often become very abundant and so completely destroy the 
inner bark that they starve out a great part of the scolytid broods, 
which develop more slowly. 
The species of two genera of pine-stump borers, Asemwm Esch. and 
Criocephalus Muls., are considered collectively, as the adults are very 
similar and the character of the work is about the same. They are 
elongate, shghtly flattened, brownish-black beetles, having the sides 
of the thorax rounded but never margined. The eyes are somewhat 
emarginate and the hgula corneous. The larvae are easily recogniz- 
able by the heads being wider than long, the sides bearing dense re- 
curved hairs, and the mandibles being sharply pointed with a striated 
plate in the inner face. The pronotum and ampullae are velvety or 
asperately pubescent, and the last segment bears two chitinous spines 
or points on the dorsal surface. Legs are present. 
Species of Asemum and Criocephalus are found throughout the 
United States in pines, spruces, and related conifers. A. moestum 
Hald. and (. obsoletus (Rand.) are the species most commonly met. 
The adults appear from early in the summer to early in the fall and 
deposit eggs under bark scales of recently cut or dying trees. The 
larvae mine the sapwood or heartwood, making extensive burrows 
filled with a mixture of fibrous and pelletlike frass. When abundant 
they destroy large portions of the sapwood. From 1 to 3 years (more 
commonly 2 years) are required to complete development. ‘These 
insects cannot be considered of much economic importance, as they are 
usually found only in the stumps of felled trees or in standing dying 
trees in the woods. They contribute to the decay of Dendroctonus- 
killed trees by destroying the base and roots and thereby causing trees 
to fall that might otherwise stand for some years. 
Atimia confusa (Say), the small cedar-bark borer, is a small, 
rather stout beetle from 6 to 10 mm. in length, of a mottled gray to 
slaty color, covered by scattered pubescence and irregular shining spots. 
The thorax is wider than long, rather quadrate, and the tips of the 
elytra are truncate. The larva is slender, tapering, and rather quad- 
rangular because of the strongly lobed and projecting ampullae. ‘The 
head is wider than long, with dense recurved hairs on the sides, and 
the pronotum is dark, and velvety pubescent, except for an irregular 
glabrous area in the center. Two spines occur on the last segment, and 
legs are present. It feeds beneath the bark of cedars and junipers 
and makes a pupal cell in the sapwood. It attacks cedars, junipers, 
and related trees throughout the Eastern and Central States. 
The adults appear very early in the spring, with the first signs of 
plant.activity, and again early in the fall and lay their eggs beneath 
the bark scales of recently cut trees. The larvae feed entirely between 
the wood and bark, packing fibrous frass behind them. Late in sum- 
mer most of the brood goes into the sapwood to construct simple pupal 
cells plugged with wads of fibrous frass. Many emerge the same sea- 
son, but others may overwinter as adults or larvae and emerge early 
the next spring. Rustic work constructed from cedars and junipers 
is attacked by these insects unless it has been properly seasoned. ‘They 
