THE GENUS DENDROCTONUS. 
101 
Forest, Colorado; Fredonia, Ariz. ; Kanab, Escalante, Provo, Aqua- 
rius National Forest, Utah, and at Keystone, Wyo. It is repre- 
sented in the forest-insect collection of the Bureau of Entomology by 
more than 10,000 specimens. 
BIBLIOGRAPHY. 
Hopkins, 19026, p. 10; Hopkins, 1902c, p. 21; Hopkins, 1903a, p. 59; Hopkins, 19036. 
pp. 275-282; Hopkins, 1904, pp. 41, 43, 44; Hopkins, 1905, pp. 1-24; Hopkins, 1906 
p. 4; Hopkins, 1907, p. 162; Hopkins, 1909, pp. 109-114. 
No. 11. THE JEFFREY PINE BEETLE. 
(Dendroctonus jejreyi Hopk. Figs. 60, 61.) 
The Jeffrey pine beetle is a stout, 
black, cylindrical barkbeetle 6 to 
8 mm. in length; the head broad, 
convex, with faint grooves behind 
and usually in front of the mid- 
dle; the prothorax stout, broad, 
shining, the sides suddenly nar- 
rowed toward the heatl and the 
punctures fine ; the elytra with mod- 
erately coarse rugosities between 
the rows of punctures, which are 
distinct on sides, the declivity with 
a few long hairs, the striae on 
grooves narrow, and the interven- 
ing spaces broad and roughened with 
coarse granules. (See fig. 60.) It 
attacks living and dying Jeffrey pine 
and yellow pine, in the Yosemite 
National Park and San Bernardino 
County, California. It excavates 
long, nearly straight, egg galleries 
through the inner bark, and grooves 
the surface of the wood; the larval mines extend from the sides, 
exposed in the inner bark. The stout, whitish, grublike larvae trans- 
form to pupae and adults in cells at the end of the burrows, and the 
broods occupy the bark on the main trunk. The infested trees are 
indicated by pitch tubes on the trunks in the summer and fall, and 
during the following Ma}^ to August by the fading and yellowish 
foliage. 
Fig. 60.— The Jeffrey pine beetle {Dendroctonus 
jeffreyi): Adult, Greatly enlarged. (Au- 
thor's illustration.) 
