part of the United States and southeastern Canada and breeds in 
various species of ash. The adult is grayish-brown with nearly 
black markings and is about 2 to 3 mm. long. Winter is spent in 
the adult stage in tunnels in the bark of living or felled trees. 
The adults emerge in the spring and fly to the trunks or limbs 
of recently felled, dying, or seriously weakened trees to breed. 
Egg galleries are constructed between the bark and wood, both 
of which are deeply engraved. The galleries are biramous and 
transverse, the two arms being connected by a short tunnel or 
nuptial chamber just below the entrance hole (fig. 92). Eggs are 
laid in niches along the sides of the gallery. The larvae feed away 
from the gallery, following the grain of the wood and deeply en- 
graving it. Pupation occurs in deep oval cells between the bark 
and wood. There are one to three generations per year, depending 
on location. As the adults bore into the bark to hibernate, they 
sometimes cause slight injury; otherwise, the species causes little 
or no damage. 
The genus Hylurgopinus Swaine is monotypic, only one species 
occurring in North America. It is distinguished by its seven- 
segmented antennal funicles, the strongly chitinized first two 
sutures of the antennal club, and the widely separated fore coxae. 
The native elm bark beetle, Hylurgopinus rufipes (Highh.), oc- 
curs in southern Canada and throughout eastern United States 
north of Alabama and Mississippi. It breeds in various species 
of elm; also, reportedly, in basswood, ash, and wild cherry. The 
adult is brownish-black, thinly clothed with short, stiff yellow 
hairs, and from 2 to 3.5 mm. long (fig. 98). The head is convex, 
thickly punctured, and nearly invisible from above; the antennal 
club is almost twice as long as wide; the pronotum is narrow in 
the front, densely punctured, and reddish at the rear; the elytral 
striae are composed of deep punctures; and the legs and abdomi- 
nal sternites are red. 
COURTESY OF 
DUKE UNIV. SCH. OF FOREST. 
FIGURE 92.—Transverse egg 
galleries and vertical larval 
tunnels of Leperisinus ac- 
uleatus, the eastern ash 
bark beetle, in white ash. 
