12 



top of the tree, and excavates three or four long longitudinal galleries 

 from a single entrance and broad central chamber (PI. II). The cen- 

 tral chambers and galleries are usually grooved in the surface of the 

 wood, but can be readily distinguished from those made by the Oregon 

 Tomicus. It is a common and 'widely distributed species over the 

 greater part of the pine-producing areas of the United States from 

 the Atlantic coast to and including the Rocky Mountain region. a It 

 attacks all of the Eastern and Southern pines, and doubtless several 

 of the Western pines in addition to the rock pine, in which it was 



found in large numbers 

 in the Black Hills region. 

 The wood - engraving 

 Tomicus (Tomicus ccela- 

 tus Eichh.). This is a 

 much smaller and more 

 slender bark beetle than 

 the two preceding spe- 

 cies. Individuals vary 

 in length from 2.6 mm. 

 to 3.2 mm., and in color 

 from dark red to dull 

 black. This is also a 

 common, widely distrib- 

 uted, and variable spe- 

 cies. It extends from 

 the Atlantic to the Pa- 

 cific, and infests all of 

 the Eastern and South- 

 ern pines and spruces. A 

 variet} T (var. scopulorum 

 n. var.) was found in the 

 rock pine of the Black 

 Hills, and has been col- 

 lected by the writer from 

 a number of other spe- 

 cies of Western pines. It attacks and breeds in the inner bark on the 

 roots, trunks, and branches of weakened arid dying- standing trees of 

 all ages and sizes, from the very young to the oldest and largest. It 

 also breeds in immense numbers in the stumps, logs, and tops of 

 recently felled trees. 



The dark-red turpentine beetle (Dendroctonus valens Lee.) This is the 

 largest of the known North American bark beetles. The adults vary 

 in length from 6 mm. to 9.5 mm. It attacks the bark on the base of liv- 



FIG. 4. Work of the Oregon Tomicus. Primary galleries en- 

 graved in surface of wood. Central chamber extending into 

 wood. Reduced about one-half (original). 



a The Western form seems to be sufficiently different in some minor characters to 

 warrant this distinction in variety name occidentalis. 



