THE GENUS DENDROCTONUS. 



49 



BASIS OF INFORMATION. 



The preceding information on the western pine beetle is based on 

 investigations by the writer at McCloud, Cal., at Grants Pass, Oreg., 

 near Spokane, Wash., and at Moscow, Idaho, April and June, 1899, 

 and in the Yosemite National Park and Yosemite Valley, California, 

 June, 1904; by Mr. J. L. Webb, at Moscow and Troy, Idaho, Septem- 

 ber and October, 1900, and at Centerville, Stites, Kooskia, Grimes, 

 Placerville, and Smiths Ferry, Idaho, April to September, 1905; by 

 Mr. H. E. Burke, at Smiths Ferry, Idaho, October, 1904, in the Yosem- 

 ite National Park, at Wawona, and in the Yosemite Valley, Califor- 

 nia, June to August, 1906, and at Joseph, Oreg., in 1907, and by 

 Mr. V. S. Barber, at Sterling and Chester, Cal., in 1908. Additional 

 localities through correspondence and from other collections are 

 Badger, Ballard, and the Santa Barbara Na- 

 tional Forest, Cal.; Winthrop and Auburn, 

 Wash.; Pokegama, Oreg., and Missoula, Mont. 

 The species is represented in the forest-insect 

 collection of the Bureau of Entomology by sev- 

 eral hundred specimens. 



BIBLIOGRAPHY. 



Hopkins, 1899a, p. 395; Hopkins, 18996, pp. 13, 20, 26; 

 Hopkins, 19016, pp. 66, 67; Hopkins, 1902c, p. 21; Hopkins, 

 1904, p. 18; Webb, 1906, pp. 17-30; Hopkins, 1907, pp. 

 162-163; Hopkins, 1909, pp. 81-85. 



No. 2. THE SOUTHWESTERN PINE BEETLE. 



(Dendroctonus barberi Hopk. Figs. 12-14.) 



Fig. 12.— The southwest- 

 ern pine beetle (Den- 

 droctonus barberi): 

 Adult. Greatly enlarg- 

 ed. (Author's illustra- 

 tion.) 



The southwestern pine beetle is a small, rather 

 stout, light to dark brown barkbeetle, from 2.5 

 to 4.7 mm. in length, with a broad grooved head, sides of the pro- 

 thorax slightly narrow toward the head, elytra with moderately 

 coarse rugosities, and elytra and declivity without long hairs. (See 

 fig. 12.) It attacks healthy, injured, and felled western yellow pine 

 in southern Colorado and Utah and in the mountains of Arizona, New 

 Mexico, western Texas, and northern Mexico. 



The adults excavate winding, transverse, egg galleries (fig. 13) 

 through the inner bark and mark the surface of the wood. The lar- 

 val mines are rarely visible on the inner surface of the bark, but 

 extend through the middle portion and into the outer corky portion, 

 where the larvae transform to pupae and adults. The presence of 

 this species in standing timber is indicated by pitch tubes on the 

 trunk similar to those made by the western pine beetle (figs. 8, 9) 

 and by the fading yellowish to red foliage. 

 89535— Bull. 83, pt. 1—09 5 



