Dorsal marking an inverted Y, the apex surrounded by 
a depressed shiny diamond-shaped area; mandible tri- 
dentate; breeds in conifers 0:08 Trachykele 
12. First abdominal segment smaller than the rest; plates of 
prothorax whitish opaque; prothoracic grooves dark 
brown: breeds intredbudims:. 4a Serer Ptosima 
First abdominal segment broader than the second 
Acmaeodera 
13. First segment as broad or slightly broader than the 
others; body gradually tapering to the twelfth seg- 
ment; slightly wedge-shaped 20... Brachys 
First segment narrower than the others; body tapering 
both ways from about the middle, more acute at the 
posterior end; spindle-shaped ...................... Pachyschelus 
14. Dorsal plate marked by 2 moderately separated dark- 
brown lines which converge anteriorly; breeds in alder 
Eupristocerus 
Dorsal plate marked by a single median bisecting line; 
attacks various hardwoods) 222-2 === Agrilus 
Acmaeodera pulchella (Hbst.), the flatheaded bald cypress sap- 
wood borer, breeds in bald cypress in the Eastern and Southern 
States. The adult is blue-black to blackish and about 6 to 10 mm. 
long (in some individuals the thorax is dull bronze and the wing 
covers and outer angles of the thorax are marked with spots and 
patches of waxy yellow). Full-grown larvae are about 13 mm. 
long and the prothoracic plates are marked by brownish median 
grooves or lines. The sapwood of dead and dying cypress trees 
and recently cut cypress logs is subject to severe attack and dam- 
age. The removal of unseasoned logs from the woods before the 
adults fly in the spring, or the girdling of trees in the fall that 
are to be felled in the spring, should aid in the reduction of 
damage. 
The two-lined chestnut borer, Agrilus bilineatus (Web.), occurs 
in southern Canada and throughout Eastern United States. It 
breeds in various hardwoods, preferably chestnut and several of 
the oaks. Trees weakened by drought, defoliation, or other ad- 
verse factors are usually attacked. Adults are about 6 to 12 mm. 
long, subcylindrical, and black with a more or less greenish tinge. 
The sides of the thorax and elytra are clothed with light golden- 
yellow pubescence, and each elytron is marked with a stripe of 
the same color. The larva is slender, considerably flattened, about 
25 mm. long, and has two spines at the posterior end. 
Winter is spent in the prepupal stage in cells constructed in the 
outer layers of the sapwood and sometimes in the bark. In the 
spring, the adults emerge through characteristic D-shaped holes 
in the bark. Eggs are deposited on the bark in late spring or 
early summer. Young larvae bore directly through the bark to 
the phloem. There they excavate winding mines in the inner bark 
and outer wood of the main trunk and larger branches. These 
mines run back and forth in all directions (fig. 47), and in the 
event of heavy attack, they girdle and kill the trees. Attacks 
usually begin in the tops of trees and are extended downward 
160 
