INSECTS AFFECTING FOREST TREES. 5I9 



Insects Affectino; tl)e I^alsam. 



The fir or balsam is one of the prettiest and most characteristic trees of the 

 Adirondack region, and though its wood may not have a high commercial value 

 the insects infesting it are worthy of brief notice. 



INSECTS ATTACKING THE TRUNK. 



BALSAM BARK BORER. 



Touiiots balsaiiiciis Lee. 



A small brown or nearly black beetle, about ■'^ ,\ of an inch in length, may be 

 found working in large numbers in the inner bark of this tree. The reddish tops of 

 the affected tree is a rather characteristic sign of the insect's presence. Our own 

 observations lead us to conclude that this beetle is generally distributed throughout 

 the Adirondacks, where it exhibits a decided preference for the balsam, though it 

 does not hesitate to attack spruce and white pine. It has been found in the Adi- 

 rondacks in both of the latter trees several times, once in arbor vitte, and has been 

 obtained from hemlock. There is little doubt but that this insect can and does kill 

 healthy trees. A balsam ten inches in diameter just beginning to die, as was shown 

 by its reddening top, \\as cut down August 14, 1900. This insect was found in all 

 stages and in large numbers from the base of the tree almost to its tip, some 50 feet 

 high. The bark along much of this distance appeared to be healthy and the lower 

 limbs had not begun to show any signs of weakness. No other insect had affected 

 the vitality of this tree, so far as could be determined. Such balsams were to be 

 met with here and there in the woods and it was stated that many of these trees 

 had been affectecl in this way a few years earlier. Numerous dead balsams here and 

 there attested to the truth of this assertion. 



This insect was associated with Toinicus piiii Say and species of Pityogenes, in 

 white pine. It was obtained with Crvphnliis striatitlatus Mann, and also with Poly- 

 graphus rufipciuiis Kirby from spruce. Toinicus caclatus Eich. was found with it in 

 balsam. 



Description. This is our smallest species of Toinicus, the adult beetle being only 

 about = -^, of an inch long. It is rather slender in form and v.iries from light 

 brown to almost black in color. The rather coarse, light bvown hairs are quite con- 

 spicuf)us near the posterior end of the elytra and the possession of these hairs 

 enables one to separate it from the ]Meceding species. The excavation of the 

 declivity is com])aratively slight and bt-ars on each side three small independent, 



