62 THE EEPOET OF THE No. 36 



particularly abundant in 1910 and 1911, when practically every birch leaf was the 

 home of several of the little caterpillars. About the end of July, this season, I first 

 began to notice the work of the young caterpillars, and by the end of August the 

 birch leaves were pretty well skeletonized and many of the larvae were spinning their 

 curious elongated ribbed cocoons. Caterpillars were constantly falling from a birch 

 overhanging the cottage verandah and spinning their cocoons upon the floor, and 

 in the cracks between the boards. The birch leaves turned yellow and fell very 

 early this season, possibly as a result of the attacks of these larvae. 



Birch and several other trees were also attacked this year by large numbers 

 of lace-bugs (Corythuca arcuata, Say). These insects puncture the leaves chiefly 

 about the midrib and larger veins on the underside, thus rendering them pale and 

 patchy in appearance. 



Of wood-boring insects the one whose Avork was by far the most con- 

 spicuous is the large black carpenter ant {Campontus hercuieanus, L.). A 

 good many trees that were blown over by the storm were more or less weakened 



Fig. 28. Flat-headed 

 Borer — larva, pupa 

 and beetle. 



by the work of this insect. It does not attack the living wood but excavates irregu- 

 lar galleries in the dead heart wood, thus weakening the tree and rendering it un- 

 marketable. Pines, balsams, poplar and red oak were all conspicuously attacked- 

 by this ant, particularly the trees on the wooded part of the sandy ridge, where 

 most of the pines and many other trees showed basal wounds, the result of ground 

 fires ihany years ago. Some of these wounds had been completely closed by the 

 new growth of tissue, but the dead wood beneath was, in all cases examined, honey- 

 combed by carpenter ants. 



Fallen oaks were not yet attacked to any extent by borers. A few young 

 cerambycid larvae of an undetermined species were found under the bark of one 

 sound tree, only rtcently dead, but, with this exception and that of the ants, the 

 only wood-eating insects found in the oaks were a number of larvse, one pupse and 

 several imagoes of the small stag-beetle {Ceruchus piceus, Web.). These were taken 

 from the rotten and partly decayed heart-wood of a large tree which was still alive 

 when it was blown over in the storm. 



In several fallen balsam poplars were found a considerable number of larvae 

 of a CTirysohotliris, which I take to be the common flat-headed borer (C. femorata, 

 Fabr.), many of which were too large to have entered the trees during the same 

 season. Most of the grubs were found about the end of August in their flat ir- 

 regular excavations in the inner bark and superficial layer of the wood, 'but some 

 had begun to extend their galleries deeper into the wood . 



