INSECTS BOEING IN THE ROCKY MOUNTAIN SPRUCE. 857 

 The following insects also occur on the ispruce : 

 Order Lepidoptera. 



43. Eacles imperialis Hiibner. This caterpillar is reported by Mr. Hulst 



to feed on the spruce. (Bulletin Brooklyn Ent. Soc, ii, p. 77.) 



44. Grapholitha bracteatana Fernald, Comstock's 1880 Eep. Dept. Ag., 



p. 265. Affecting Abies bracteata. 



INSECTS INJURIOUS TO THE ROCKY MOUNTAIN SPRUCE ANB 



DOUGLASS SPRUCE. 



Abies menziesii and A. douglasii. 



AFFECTINa THE TRUNK. 



1. The rocky mountain spruce timber-beetle. 



Dryoccetes affaber Mannh. 



Order Coleoptera ; family Scolytid.e, 



This beetle occurred (July 7, 1875) in abundance in all stages in a 

 growth of Abies menziesii,* the common spruce of the Rocky Mountains, 

 at Kelso's Cabin, 11,200 feet elevation, on the road to Gray's Peak. 

 It bores into the bark and near the sap-wood in all directions, its bur- 

 rows resembling those of Tomicus pini, with which it is associated, 

 being irregular but much smaller. 



The larva is of the usual form of those of the family, being cylindrical and of the 

 same thickness throughout, with the end of the body full and suddenly rounded ; 

 segments convex, especially the thoracic ones, and slightly hairy. Head two-thirds 

 as wide as the body, rounded, honey-yellow. Length, 0.15 inch. 



The pupa is much like that of T, pini, with two anal 

 soft, sharp tubercles. As my specimens are further 

 advanced than those of T. pint, the wings being free 

 from the body, and the abdomen longer, it is impossi- 

 ble for me to draw up a good description. In one ex- 

 ample the pupa had retained the larval head, but it 

 was split behind so as not to interfere, probably, with 

 the development of the adult beetle. ^i, — ^ 



The beetle differs from Tomicus pini in its much Fig. 291. -a, larva; 6, pupa; c, bee- 

 smaller and slightly slenderer body. The head and tie of the Eocky Mountain spruce 



^, i ,, . , , ^, ^ /• XI timber beetle.— From Packard, 



prothorax are two-thirds as long as the rest of the 



body. The abdomen is not scooped out at the end as in T. pini, but truncated, 

 moderately rounded, and the end of the abdomen reaches to the end of the wing- 

 covers, which are square at the end instead of excavated as in T. pini. Color red- 

 dish brown, much as in T. pini. The body is covered with fine, stiff, straight hairs. 

 Length, 0.14. (Packard in Hayden's Report for 1875.) 



This insect is said by LeConte to occur in the Lake Superior region, 

 British Columbia, and Alaska. 



* This tree was kindly identified for me by Mr. Sereno Watson, from specimens of 

 the leaves and cones sent him for identification. 



