Insect Life on the WesteTn Arctic Coast of America 35k 
Groves of white spruce (Picea canadensis) become frequent farther up the 
river. The largest trees were 30 feet high and about 5 feet in circumference 
near the ground. Even stunted trees were seen from their rings to be about 
fifty years old, and the largest must have been nearly five hundred years. 
Samples were secured of the rich growth of hchens found on the dead trees and 
on the dead branches of the living trees. Many of the trees were attacked by 
insects and very few young trees were. seen, the growth as a whole indicating 
longevity. Dr. Richardson ascribes the appearance of the forest — in particular 
the dead trees and stumps — to a deterioration of the climate, fires and exposure 
to cold north winds. Insects, however, undoubtedly contribute to the destruction 
and many dead trees have been killed or injured solely by bark beetles and 
cerambycid larvae, which were as numerous in some trees as in trees farther 
south. ^ 
Owing to their scattered distribution and consequent liability to exposure, 
the percentage of trees, above a certain size, attacked by insects is larger in this 
region than farther south. Living as they do under the bark, the insects are not 
greatly influenced by the cold.- 
Three species of bark beetles, Pohigraphus ruflpennis, Pity ophthor its nitidus, 
and Dendroctomis johanseni, were found in the dead trees, either under or in the 
bark,^ but the third species was found in only one tree, under the bark at its 
base. All the beetles were dead, and no immature stages were observed.* 
Tunnels of Cerambycid larvae were common upon the dead trees. Dead 
larvae, cast skins, or their hymenopterous parasites were found in these burrows, 
occasional " foreign " insects which had crawled into them later, and a few 
cerambycid imagines, which possibly belonged to the tunnels. 
The living trees contained the Polygraphus and Pityophthorus mentioned 
above and Carphoborus andei ^oni, but bark beetles were not nearly so numerous 
as upon the dead trees. 
Depredation to the living trees by boring insects is extensive. The bark- 
boring — the more destructive— are represented by Merium proteus and the 
wood-boring bj" Neoclytus muricatulus and Xylothrechus undulatus. Most of 
the larvae were heavily parasitized by immature stages of hymenopterous insects, 
but all efforts to rear were unsuccessful. 
Of harmless insects a few sawfly larvae in cocoons were found in the ceram- 
bycid galleries; they were of two kinds, the smaller a light brown, with dark, 
dorsal streaks; the large, light green. This green larva was reared (No. 46) 
and emerged July 13, 1915, when it proved to be a new species, Pontania quad- 
rifasciata MacGillivray. 
Under spruce bark, or in the cerambycid tunnels, spider webs, fragments of 
flies and beetles, etc., and a winged ant were observed. This ant and a similar 
specimen! found November, 1913, in an old bird's-nest about 30 miles up 
Sadlerochit river, represent the only ant material secured by the expedition, 
and the two localities indicate the probable northern limit for ants in North 
America.^ 
No other insects were seen along the lower Coppermine river, except a few 
bot fly-grubs (Oedemagena tarandi) from caribou above Bloody falls. Franklin 
(1st Expedition) states that sandflies were numerous and troublesome in the 
August evenings, the temperature then being 53 degrees F. at about 67° 12' 
North; and Richardson (Arctic Searching Expedition) was annoyed by these 
insects in the same region as late as September 8, in the evening. 
1 Johansen, F., Can. For. Jour., XV, 7, July, 1919, pp. 303-5. 
2 See Rept. of Can. Arct. Exped., 1913-18, vol. Ill, Part E, Coleoptera, by J. M. iSwaine. 
s A section of a trunk was preserved. 
*The observations were made in February, 1915. 
5 Formica hereculeana recorded from Back's Overland Expedition (Great Fish river) by 
Children. 
16579—31 
