The genus Orthotomicus is represented by one species in eastern forests. It is 
closely related to the genus /ps, but the aduits differ in having obliquely truncate 
rather than flattened antennal clubs and feeble rather than well-developed teeth on 
the margin of a shallowly concave declivity. 
Orthotomicus caelatus (Eichhoff) occurs throughout the East, Lake States, and 
eastern Canada. It commonly breeds in thick bark on stumps and logs or at the 
bases of weakened or dying pines, spruce, larch, and balsam fir. The adult is dark 
reddish-brown to nearly black and from 2 to 2.3 mm long. Short, radiating egg 
galleries originate at central nuptial chambers, and from one to six eggs are laid in 
large niches or pockets along their sides. Specimens of a morphologically closely 
related species, possibly a variety, have been collected from the twigs of fire-killed 
young loblolly pines in North Carolina, where they were apparently breeding as 
well as mining out the pith and wood. Adults were also reared from dry twigs and 
the tips of longleaf pine logging slash (76). 
Among the bark beetles, the genus /ps ranks next in importance to the genus 
Dendroctonus in its destructiveness to pines and spruces. Infestations normally 
occur in lightning-struck trees and those recently felled by windfalls, snow- 
breakage, and logging, and in road slash. However, when heavy populations 
develop in this material, the adults emerge and attack and kill adjacent groups of 
young healthy pines and the tops of older trees. Infestations in green timber are 
usually of short duration unless the trees have been weakened by drought, fire, or 
other disturbances. Spot- or group-killing in pulpwood or pole-size trees or, less 
often, in mature stands is characteristic of outbreaks. Widespread outbreaks occur 
frequently, and losses may be extremely severe. More than 3 million cubic meters 
of commercial timber and more than 1.8 billion cubic meters of pulpwood were 
killed in the South Atlantic and Coastal States during the period of 1952-55. It is 
estimated that annual losses of 765 million cubic meters of pulpwood are incurred 
in Florida alone. The North American species of /ps have been arranged into a 
number of taxonomic groups (592, 593, 594, 595, 596, 597, 598, 599, 600). 
The male initiates the attack by boring through the bark to the wood and 
constructing a nuptial chamber. Here he 1s joined by one or more females (typically 
three), each of which excavates an egg gallery in the phloem. These galleries radiate 
in all directions from the chamber through the phloem, but eventually tend to run 
parallel with the grain of the wood. The resu!tant pattern tends to form a rough Y or 
| shape. Eggs are deposited in small niches at irregular intervals along the sides of 
the gallery, and the larvae tunnel in the phloem until fully grown. Pupation occurs 
in cells hollowed out in the inner bark. Young aduits feed for a short time beneath 
the bark and then emerge, several often using the same exit hole. In northern areas, 
the winter is spent in the adult stage under the bark of the brood tree or in the litter 
below the infested tree. In the South, winter may be spent in the bark in all life 
Stages. 
Ips calligraphus (Germar), the six-spined engraver, occurs through eastern 
America. Although it breeds in any species of pine available, its distribution in the 
Northeast coincides with that of pitch pine. Trunks, stumps, and large limbs of 
recently felled trees appear to be favored for breeding purposes, but the trunks of 
apparently healthy pines are also attacked, especially in the Southeastern States 
where it frequently attacks in concert with other /ps and Dendroctonus species. 
Attacks on living trees usually occur on the lower portions of trunks with diameters 
of 15 cm or more. In the South, this is one of the first species to attack drought- 
stressed trees. 
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