VIII. BORERS IN DRY, SEASONED WOOD. 
The larvae of a number of species of the family Cerambycidae, 
belonging to several genera, are often referred to as “powder-post 
borers” because of their common habit of boring for year after 
year in the same wood, eventually leaving nothing but a thin 
outer shell filled with a mass of powder. Certain species attack 
only recently cut wood. Under normal conditions the life cycle of 
the progeny would be completed in a year or two. But if the 
wood, after being attacked, is placed in buildings or stored in 
drier conditions, the larval period may be prolonged for several 
years. Damage is often severe to stored lumber exposed to attack 
before storing, to structural timbers in houses such as rafters and 
beams, and to bridge timbers. 
1. Three ocelli on each side of the head 
Hylotrupes bajulus 
One ocellus on each side of the head |. 2 
2. Underside of mouth frame with 4 small projecting tu- 
bercles; in coniferous wood 
Callidium antennatum hesperum, C. texanum 
Underside of mouth frame without tubercles 
Tn ba nt OO re ee eae Chlorophorus annularis 
ins NaTrgwo0dse fe (ano etc Ve ae a tie ne eee oles 
3. Legs smaller than palpi. 
A smooth white triangular are on venter of prothorax 
Smodicum cucujiforme 
Underside of prothorax not so marked; legs very 
small; body dull, finely granulated above and below 
Neoclytus caprea; N. acuminatus 
ers larver thancpalpl «tcc a Eburia 
The locust borer, Megacyllene robiniae (Forst.), one of the most 
important of the Cerambycids, occurs in eastern Canada and 
throughout most of the United States, wherever its host, black 
locust, grows. The adult is about 18 mm. long. The jet-black 
background is marked with bright yellow bands extending across 
the thorax and wing covers, the third band on the wings being 
W-shaped. The legs and antennae are moderately long and yel- 
low. Full-grown larvae are robust and about 25 mm. long. 
Adults are present in late summer or early fall, but are most 
abundant during September. They are commonly seen feeding 
on the pollen of goldenrod blossoms during morning hours. Later 
in the day, sometimes well after sunset, they are usually seen 
running up and down the trunks of black locust trees in search of 
oviposition sites. Eggs are usually deposited in rough bark crev- 
ices and around wounds on the trunks of living trees. Newly- 
hached larvae bore into the inner bark and construct small hiber- 
nation cells in which they spend the winter. Activity is resumed 
in the spring when the leaf buds begin to swell. At this time, 0oz- 
ing sap may be seen around larval entry holes in the trunk. The 
larvae soon bore into the wood where they continue to feed until 
mature, around mid-July. During this period they construct ex- 
tensive tunnels throughout the heartwood (fig. 583A). As the larva 
grows, it enlarges its tunnel to the exterior, through which it 
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