72 



THE SCOLYTID BEETLES. 



lection of the Bureau of Entomology by 65 specimens in the West 

 Virginia Agricultural Experiment Station collection and by more than 

 150 in the general Bureau of Entomology collection. 



BIBLIOGRAPHY. 



Hopkins, 1892a, pp. 64-65; Hopkins, 18926, p. 353; Schaufuss, 1892, p. 316; Hopkins, 

 1893a, pp. 187-189; Hopkins, 18936, p. 143; Hopkins, 1893c, pp. 186, 213; Hopkins, 

 1893d, pp. 123-129; Hopkins, 1894, p. 292; Hopkins, 1894a, pp. 71-76; Hopkins, 1894c, 

 p. 348; Lintner, 1895, p. 500; Hopkins, 1896, pp. 246, 250; Hopkins, 1897a, pp. 29-11; 

 Hopkins, 18976, pp. 35-36; Hopkins, 1897c, pp. 79, 94-95, 147-151; Chittenden, 1897, 

 pp. 67-75; Hopkins, 18985, pp. 104-105; Schwarz, 1898, pp. 81-82; Hopkins, 1899a, 

 pp. 394-414, 448; Hopkins, 18996, pp. 11, 13, 14; Chittenden, 1899, pp. 55-56; Hopkins, 

 19026, p. 21; Hopkins, 1902c, p. 20; Hopkins, 1903a, p. 59; Hopkins, 19035, pp. 270-275, 

 281; Hopkins, 1904, pp. 41, 42, 44; Felt, 1905, p. 6; Hopkins, 

 1906c, p. 80; Webb, 1906, pp. 20-22; Hopkins, 1907, p. 163; 

 , Hopkins, 1909, pp. 90-95. 



No. 5. THE ARIZONA PINE BEETLE. 

 (Dendroctorms arizomcus Hopk. Pigs. 33, 34.) 



The Arizona pine beetle (fig. 33) is a somewhat 

 elongate, brown to black beetle, from 4 to 5 mm. 

 long, with broad groored head, sides of prothorax 

 but slightly narrowed toward the head, finely to 

 rather coarsely punctured, and elytra with slightly 

 coarse rugosities toward the base and declivity, the 

 latter with a few long hairs. (Seefig.34.) It attacks 

 healthy, injured, and felled western yellow pine in 

 central Arizona, and evidently excavates galleries 

 similar to those of the southwestern pine beetle, 

 with which it is usually confused. The larvae 

 make concealed food burrows in the inner bark, and transform to 

 pupsB and adults in individual cells in the outer bark. Like the other 

 species, its destructive work would be indicated by pitch tubes on 

 the trunk and by the fading yellowish to reddish foliage. 



SEASONAL HISTORY. 



This species was not recognized as distinct from the southwestern 

 pine beetle until after the principal field observations had been made, 

 and while many specimens were collected they were nearly always 

 associated with the latter in similar galleries; therefore there is 

 somewhat meager evidence on which to base conclusions relating to 

 seasonal history, habits, etc. Apparently, however, its habits are 

 in most respects similar to those of the southwestern pine beetle, 



Fig. 33.— The Arizona 

 pine beetle ( Dendroc- 

 tonus arizonicus): 

 Adult. Greatly en- 

 larged. (Author's il- 

 lustration. ) 



