The Coleoptera collected by the Canadian Arctic Expedition, 
1913-18. 
FOREST INSEC^TS. 
The Families IPIDAE, CERAMBYCIDAE and BUPRESTIDAE. 
B3" J. M. SWAINE, 
Chief, Division of Forest Insects, Entomological Branch, Department of Agriculture, Ottawa. 
The forest insect collection was made principally at " Camp creek " and 
along the adjoining river banks, on the east side of the Coppermine river, 
Northwest Territories, just below Sandstone rapids. Only a few isolated 
specimens were obtained in other localities. Along the river near Sandstone 
rapids is the northern limit of forest trees and to examine this Mr. 
Johansen made a special trip of over 50 miles. The trees here are white 
spruce, mostly stunted and growing in a very open stand, as is well shown 
in the accompanying illustration. Plate I. The examination was made in 
February at a temperatu.re of about 50 degrees below zero. In addition to 
pieces of bark containing many dead beetles a section of a trunk and part of a 
dying branch were brought back by Mr. Johansen. 
A large number of trees were dead or showed dead and dying parts, and a 
suj)erficial examination of these suggested that many of the dead standing 
trees had been killed by the bark-beetles whose galleries were extremely abundant 
on the wood sin-face wherever this was laid bare. 
Of the bark-beetles a species of Dendrodonus was found at the base of 
one dead tree; Polygraphus rufipennis Ky. and Pityophthorus nitidtis Sw. appar- 
ently occurred in abundance, while an undescribed species of Carphoborus 
was probably less numerous and is represented in the collection by only two 
specimens exposed in a tunnel in one of the specimen sticks while removing 
the bark in the laboratory. Polygraphus rufipennis and Pityophthorus nitidus 
were the most numerous in the dead trees and occurred throughout the trunk. 
Usually they were well chitinized and dark in colour. These species were 
found chiefly in timber of medium size, rarely in very young or very old trees. 
The Dendroctonus beetles came entirely from the base of one large spruce which 
also carried the two smaller species {Polygraphus and Pityophthorus) in the 
upper part. There were many adult Dendroctonus beneath the bark, chiefly 
in cells in a compressed layer of frass lying upon the surface of the wood. They 
were all very light in colour and had died before maturity. Mr. Johansen 
believes that all these beetles were dead when he collected the wood. The 
cause of their death was not apparent, but was probably due to adverse weather 
conditions. 
Cerambycid tunnels cut by larvae of several species were also abundant 
in these dead trees, and had apparently been responsible, in part, for their 
death. The larger trees were usually quite without bark or had retained it 
only in patches, particulavly about the base of the trunk. The wood surface 
showed many surface tunnels of cerambycid larvae, and although no living 
larvae were found, several dead adults of Mereum proteus Ky. were taken from 
these tunnels beneath the liark. Larval skins were found and dead larvae 
which had apparently b(>en killed by parasitic hymenoptera whose cocoons, 
usually empty, w^ere found beside them. The galleries of wood-boring ceram- 
bycid larvae were also numerous in these trees, and several dead adults were 
taken from the tunnels by Mr. Johansen. 
