10 
the technical or Latin name Dendroctonus ponderosa.* The adult is a 
stout, dark-brown to black beetle, individuals of which vary in length 
from 4 to 7 mm. (about one-sixth to one-fourth inch). They attack 
living and healthy large and small pine trees, enter the bark on the 
main trunk, and each pair excavates a long, nearly straight, longitudi- 
nal gallery through the inner bark (Pl. I and fig. 1), usually grooving 
the surface of the wood. Eggs are deposited along the sides of this 
primary gallery and hatch into minute white grubs (larve), which 
excavate mines through the bark at right angles -to the primary gallery 
(fig. 1, 6). These mines are extended and enlarged as the larve 
increase in size, and when 
full grown each individual 
excavates a broad, oval 
cavity in the bark (fig. 1, 
c), in which it transforms 
to a soft, white pupa, and 
then to the adult, which 
bores out through the bark 
(fig. 1, @), and flies, with 
other adults of the same 
and other broods, in search 
of other living trees in 
which to excavate galleries 
and deposit eggs for an- 
other brood. 
SECONDARY ENEMIES. 
Many other species of 
bark beetles and other 
Fic. 2.—Work of the Oregon Tomicus ( Tomicus oregon Eichh.). bark and wood infesting 
Primary galleries and larval mines in inner bark. a, En- insects were found asso- 
trance; b, central chamber excavated through inner bark; : : : 
‘ — 
ce, egg galleries; d, location of central chamber not exca- ciated with the pr TMary 
vated through inner bark. Reduced about one-half (origi- enemy in the partly living 
ee bark of infested and dying 
trees, but none of them were found making an independent attack on 
living trees. Therefore they must be considered as secondary ene- 
mies, which follow the leader in the attack, and merely contribute to 
the rapid and certain death of the trees thus infested. 
The Oregon Tomicus (Tomicus oregont Kichh.).—This is a small red- 
dish to black bark beetle, individuals of which vary in length from 
3.5mm.to4mm. It follows closely the attack of the pine-destroying 
beetle, and enters the bark on the large and medium sized branches 
and toward the top of the main stem. Several females excavate radi- 
“This species has heretofore been erroneously identified as D. terebrans and D. 
rufipennis, and will probably be found so labeled in some collections. 
