fine hairs, and has two spots separated by a curved bar on the 
elytra. Eggs are deposited in bark crevices or in holes in the gal- 
leries of bark beetle during late spring and summer. The larvae 
feed gregariously beneath the bark, making extensive meandering 
mines. Most of the larvae mature in 1 year. 
Saperda concolor LeC. breeds in the living branches and main 
stems of poplars and willows in the Northern and Central States. 
Adults are black with fine gray hairs and are about 12 mm. long. 
Eggs are laid in longitudinal slits in the bark. Callous tissue form- 
ing over these slits causes the formation of globose galls. The 
larvae mine around the stem and then bore into wood mak- 
ing galleries about 1 inch long that run parallel to the axis. Usu- 
ally the infested twigs are not killed. Branches or small stems 
bearing numerous galls may stop growing, however, and become 
subject to wind breakage. 
Saperda obliqua Say, the alder borer, breeds in the bases of 
living alders and sometimes birch in the Northern and Central 
States. The adult is reddish-brown and from 10 to 20 mm. long. 
There are two dark bands on the thorax and four oblique bands 
on the wing covers. Larvae feed first beneath the bark near the 
base, often girdling the stem. Later they bore into the stem and 
tunnel upward for several inches. Swollen areas appear at points 
of attack on stems that survive, and large amounts of frass are 
pushed out through the openings at the egg scars. Alders in orna- 
mental plantings are frequently killed. 
Saperda fayi Bland, the thorn-limb borer, occurs in the North- 
east and Midwest and breeds in the twigs of hawthorn causing 
gall-like, gnarly swellings. Adults are reddish-brown and about 
12 mm. long. There is a white stripe on each side of the thorax 
which extends upon the base of the elytra. The elytra bear two 
white spots at the base and tip, and a single large one in between. 
Infested twigs are subject to wind breakage. S. moesta LeC. 
causes the formation of globose galls on the stems and branches 
of poplar and willow in the northern parts of the United States. 
Adults are uniformly gray and about 10 mm. long. S. lateralis F. 
breeds in dead hickory, elm, basswood, oak, and Prunus and in 
hickory sprouts. Adults are black or brownish-black with the 
head, thorax, and elytra margined by broad, red lines, and are 
about 12 mm. long. The male has a tooth on each of its claws. 
S. imitans Felt and Joutel breeds in dead hickory, willow, and 
basswood; S. cretata Newm. in living apple and the limbs of liv- 
ing hawthorn; S. mutica Say in dead willow. 
The elm borer, Hutetrapha (=Saperda) tridentata (Oliv.), oc- 
curs in southeastern Canada and throughout eastern United 
States and breeds in dead and dying American and slippery elms. 
The adult is grayish or fawn-colored and from 9 to 17 mm. long 
(fig. 61). An orange-yellow or yellowish band extends from the 
head to the tip of each wing cover, twin black spots occur below 
these bands on the thorax, and there is a cross band at the base 
of the wing covers followed by two oblique bands. Full-grown 
larvae are about 12 to 15 mm. long. 
Adults are present from late spring to late summer, and feed 
on young leaves and young twigs. Eggs are deposited in small 
holes chewed in bark crevices, usually on freshly cut logs or 
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