116 



graving the wood. The young adults cut irregular, winding food tunnels 

 deeply engraving the wood surface. 



Host trees. White Pine, White Spruce, and other pines and spruces 

 of its range. 



Distribution. Eastern Canada, from the Atlantic to northern Sas- 

 katchewan, and in Eastern United States. A series from Fort Yukon, 

 Alaska, does not differ specificially, and it will probably be found across 

 northern British Columbia and Alberta. 



Economic importance. Everywhere abundant throughout eastern pine 

 and spruce forests in slashings and dying trees; at times apparently an 

 important primary enemy. 



Ips laticollis, n. sp. 



Length, 4 mm. ; width, 1 6 mm. ; very closely allied to and only doubt- 

 fully distinct from pini Say. The pronotum is almost as wide as long, 

 with the sides parallel for more than three-fourths the length, then rather 

 distinctly sinuate behind the front margin; very coarsely asperate in front, 

 moderately punctured behind, very densely on the sides; the elytral strise 

 usually impressed, the sutural striae more strongly impressed and widened 

 behind, through the second interspace being strongly punctured on the 

 mesal side of the caudal half; the first two sutures of the antennal club 

 rather strongly bisinuate. 



The type series was taken near Ottawa, Ont. Type No. 110. 



Ips interpunctus Eichh.; Eichhoff, Rat. Tom., 241, 1878 (Tomicus'): Tomicus 

 tridens Eichh., Berl. Ent. Zeit., 274, 1868. 



Length, 4 mm. to 5 mm.; the head convex and coarsely granulate; 

 the pronotum as long as wide (sometimes slightly longer), usually rather 

 coarsely and deeply punctured behind, the elytra usually rather deeply 

 striate on the disc, with the interspaces narrow and distinctly convex; the 

 2nd interspace punctured on the caudal half making the sutural strise 

 widened behind. 



The Jasper race, from Jasper Park region, have the elytral striae more 

 often lightly impressed, except the sutural strise, which are almost invariably 

 wide and deep, and the interspaces more often nearly flat. 



In pine and spruce of southern British Columbia the typical interpunctus 

 is less common and is intergraded with the oregoni type. The two forms 

 are there taken in the same trees and apparently from the same tunnels. 

 Breeding experiments and biological studies should determine the relation- 

 ships between these series. Our very large collection from many parts of 

 British Columbia, Alberta, the Yukon, and a smaller collection from the 

 Western States, indicates that interpunctus is typically a northern form, 

 tending strongly to vary in Alberta and apparently crossed with oregoni in 

 southern British Columbia. 



Host trees. Engelmann's Spruce, White Spruce, (Sitka Spruce). 



PLATE 27. 



INNER FACE OF THE BARK OF A BEETLE-INFESTED WESTERN YELLOW 

 PINE; ALMOST THREE-FOURTHS NATURAL SIZE (AUTHOR'S ILLUSTRATION). 



1, Egg-tunnels of Dendroctonus vcdens Lee. 



2, Work of the larvae of D. valens Lee. 



3, Egg-tunnels of Dendroctonus brevicomis Lea 



