INSECT ENEMIES OF EASTERN FORESTS 185 
turnal in some literature, both species are known to fly late in the 
afternoon and between sundown and dark. July is probably the month 
of greatest abundance. The adults probably feed on leaves and flowers. 
Larvae occur in the decayed cavities of dead or dying trees and logs. 
One nest of about 40 larvae was found when a hollow jack pine log on 
the Huron National Forest was cut into firewood. In this case the 
larvae ranged from about 1 to nearly 2 inches in length. Three years 
are required for full development. All other Cetoniinae, as far as 
known, have a 1-year life cycle. The larvae are not considered very 
injurious to the host tree. 
The genus 7’richiotinus Csy. contains eight hairy, variegated species, 
sometimes referred to as “flower beetles.” In length they range from 
9 to 15 mm., and have very long, slender legs, with long claws. All 
species are apparently diurnal, and are usually found around flowering 
trees and shrubs. In Michigan, wild cherries are favorite hosts. 
They are most abundant in Juneand July. The larvae occur annually 
in dead logs and stumps since the species have 1-year life cycles. 
Neither the adults nor larvae may be regarded as injurious. 
Famitry ELATERIDAE 
The Click Beetles 
The click, or snap, beetles associated with forest trees are predomi- 
nantly vegetable feeders. They are to be found under the bark or 
in their pupal cells in the wood, often overwintering in these cells. 
One of the most interesting characteristics is their habit of snapping 
or clicking by means of a springlike prothoracic sternal spine, which 
snaps into a groove on the mesosternum. By this mechanism they can, 
when placed on their backs, throw themselves forcibly into the air, 
eventually to land feet down. As larvae they eat the soft tissues 
under dead bark or burrow in dead, often well-decayed wood. In this 
role they are of little economic importance. However, a small number 
are voracious predators and quite beneficial. 
The beetles are elongate, usually fusiform in shape, ranging from a 
few to over 40 mm. in length. They have 11-jointed, serrate antennae, 
which fit into grooves on the under side of the thorax. The larvae are 
also elongate, fusiform, and somewhat depressed or cylindrical, having 
a tough shining integument, and with the ninth abdominal segment 
often bearing a paired or a single-pointed process. The head is 
extended, labrum and clypeus fused into a nasale, mouth parts deeply 
retracted, gula reduced to a single suture, and the mandibles are of 
the grasping type without a molar structure. The legs are usually 
well developed and the spiracles bifore. 
The eyed click beetle (A/aus ocu/atus (I.)) found in hardwoods 
and A. myops (F.) in pines are large beetles, 25 to 40 mm. in length, 
grayish black and marked with two large black eyelike spots sur- 
rounded by a ring of pale scales, on the thorax. The larvae are 
elongate, depressed, yellowish forms with a heavily chitinized head and 
thorax and strong bifurcate prongs on the ninth abdominal segment. 
They are voracious feeders on other wood borers. Caged specimens 
are recorded as devouring over 200 cerambycid larvae each during 
their development. 
