ee and are only about 20 to 40 mm. long. They also have eye 
spots. 
Other predaceous species include Lacon discoidea (Web.) and 
L. avita Say which are found in pines, and Hemicrepidus bilobatus 
(Say) which occurs in hickory. Ctenicera triundulata (Rand.) 
and C. nitidula (LeC.) have been observed feeding on cocoons of 
the European spruce sawfly in Canada (541). 
FAMILY CLERIDAE 
CHECKERED BEETLES 
This is one of the most important families of insect predators 
attacking injurious forest insects. The adults are active, antlike, 
brightly-colored, hairy beetles about 3 to 13 mm. long. They feed 
on adult beetles. The larvae live in the galleries and tunnels 
of bark beetles and wood borers and destroy the immature stages 
of these insects. 
Adults are distinguished by their 11-jointed and generally ser- 
rate antennae, the outer joints of which are longer and form open 
or compact clubs. The tarsi are five-jointed and the first four 
joints bear membranous appendages. Larvae are soft-bodied, 
elongate and parallel-sided, frequently highly colored though 
often white and thin-textured, and are from 9 to 18 mm. long. 
Most species spend the winter in the larval stage. Others over- 
winter as pupae or as adults in pupal cells in the bark. The larvae 
travel down the tunnels of their hosts eating one larva after an- 
other. Some are capable of consuming several times their own 
weight of these larvae (91). A few of the more important preda- 
tors of forest insects are discussed below. 
Chariessa pilosa (Forst.) is one of the most common species in 
eastern forests. Its known hosts include several species of borers 
in hardwoods, and the smaller European elm bark beetle. The 
adult (fig. 45) is a wedge-shaped, flattened beetle about 6 to 138 
mm. long. The thorax is red with two black stripes and the wing 
covers are black with dense, fine punctures. The larva is fairly 
robust, widest at the middle, and of a bluish tinge. Adults are 
often observed feeding on insects attracted to freshly cut logs 
during the summer. 
Thanasimus dubius (Fab.) is one of the most important pred- 
ators of destructive bark beetles in eastern United States. The 
adult is a brightly-colored, hairy beetle about 7 to 10 mm. long. 
The head, thorax, and base of the wing covers are dull red; the 
antennae and legs are red to pitch black; and the wing covers are 
mostly black with cross bands of whitish hairs. The larva is 
elongate, fusiform, and purplish with brown sclerotized areas. 
Winter is spent in either the larval, pupal, or adult stages. In 
early spring, the adults emerge and fly to beetle-infested trees or 
logs and feed on bark beetles as they emerge from hibernation. 
Eggs are deposited in entrances to bark beetle galleries. Young 
larvae feed on bark beetle eggs; older ones feed on beetle larvae, 
pupae, and adults. Pupation occurs in cells in the outer bark 
(BiG 27a). 
154 
