27 



LIFE-HISTORY AND HABITS. The adult beetles leave the red-tops from the 

 latter part of June onwards, and start their egg-tunnels in the bark of the trunks 

 and larger branches of dying trees, logs, or of healthy timber. Each pair of 

 beetles cuts an entrance-tunnel through the bark to the wood-surface and ex- 

 cavates an elongated somewhat straight egg-tunnel upwards through the inner 

 bark, slightly engraving the wood. The eggs are placed singly in shallow niches, 

 which are arranged along the sides in small groups of three or four niches, with a 

 space of about half an inch between the groups. The eggs composing a group 

 are close together and often covered by a common layer of boring-dust. The 

 grubs or larvae which hatch from the eggs bore the larval-mines mainly through 

 the inner bark. They finally enlarge the end of the mine to form an oval pupal 

 cell, usually between the bark and the wood. After changing to pupae in the 

 pupal cells and later transforming to adults they finally bore round holes through 

 the bark and escape. 



Much red boring-dust is extruded from the entrance hole, and, in green trees, 

 gum-tubes form about the opening. 



This species prefers dying bark, and when such is obtainable from fires, 

 storms, or slash, the green timber is less likely to be attacked; but when the 

 beetles are in large numbers they readily enter and kill green trees of all sizes. 



DETAILED HISTORY OF THE BROODS. The winter is passed in the bark of the 

 trees infested during the previous summer, as larvae, young adults and parent 

 adults. 



The over-wintered parent adults lengthen their tunnels, or excavate new 

 ones in the infested trees in spring, and deposit eggs which develop to adults 

 probably in July and August. 



The over- wintered young adults emerge from the " red-tops" and start 

 egg-tunnels during late July, August and early September. The red-tops at 

 Sugar Lake in the last week in July, 1913, had the bark filled with larvae, pupae 

 and young adults ; and numbers of adults had escaped and were starting tunnels 

 in near-by green timber. The larvae of this generation in part develop to adults; 

 but the greater number winter in the bark as larvae. 



The over-wintered larvae transform to adults which, in British Columbia, 

 apparently emerge during late summer. There is thus one complete brood each 

 season. 



THE EFFECT UPON THE TREES. The tunnels of the adults and the larval- 

 mines kill the inner bark, and if the greater part of the trunk is infested the tree 

 usually dies in one year. The foliage of infested trees usually remains green 

 until late fall or spring, fading during fall and spring to yellow and finally to red 

 by mid-summer. If only a portion of the bark is affected at first, the remaining 

 bark is usually attacked in the following summer, or during the same season, by 

 later-appearing beetles. 



The infested trees are to be distinguished by the gum-tubes, the red 

 boring dust extruded from the tunnels and, later, by the fading foliage. The 

 foliage frequently remains nearly normal in appearance until spring; but many 

 trees fade more or less during the fall so that they may be picked out as unthrifty. 

 In selecting infested trees for cutting, gum-tubes and boring-dust on the bark 

 must be largely depended upon. It not infrequently happens that trees are 

 attacked only in the upper and' middle portions. The gum-tubes are usually 

 distinguished quite readily, but when high up the trunk they are easily over- 

 looked. The selection of the trees will be made most easily in the early fall, 

 while the gum is fresh and light in colour. 



THE CONDITIONS AT SUGAR LAKE ( VERNON DISTRICT) . An outbreak of this 

 species in the Sugar Lake and Mable Lake region has been in existence for about 

 eight years, and a body of fine white pine timber has been killed by it. Much of 



