THE GENUS DENDROCTONUS. 
73 
although it is distinctly separated by specific characters. It is more 
nearly related to the southern and smaller Mexican pine beetles than 
to any other species, and therefore it may be found that it has two 
generations, and a partial third, annually. It is also probable that 
under isolation and favorable conditions it may, like the southern 
pine beetle, become very destructive. (See " Economic features" 
and " Methods of control" under Nos. 1, 2, and 4.) 
BASIS OF INFORMATION. 
Data regarding this species were obtained through investigations 
by the writer at Williams, Ariz., September, 1902, and Flagstaff, 
Ariz., May, 1904, and by J. L. Webb at Flagstaff and Williams, Ariz., 
7T---i 
.:••.• ;>v..:**-- J.-.-,:-'-'- 1 
Fig. 34.— The Arizona pine beetle: Distribution map. (Author's illustration. ) 
May to September, 1904, and Flagstaff, Ariz., August, 1907. It is 
represented in the forest-insect collection of the Bureau of Entomology 
by over 50 specimens. 
This species can be easily distinguished from No. 2, with which it 
agrees in size, by the long hairs on the declivity of the elytra, and 
from the smaller examples of No. 8 by the fine punctures of the striae 
of the declivity, from No. 3 by the grooved head, and from No. 6, to 
which it is closely allied, by the distinctly more pubescent pronotum 
and elytra. 
BIBLIOGRAPHY. 
Hopkins, 1909, pp. 95-97. 
