26 THE REPORT OF THE No. 19 



both, bark and wood, occasionally entering the latter to a considerable depth, 

 and are invariably accompanied by coarse, sawdust like borings. 



The coarse writing bark beetle mentioned above is usually hardly more 

 than an assistant to the pine bark beetle (Toviiciis pint, Say). This latter is 

 a smaller form and confines its operations to the thinner bark of the middle 

 of the tree and on the larger branches. Its galleries, like that of its associate 

 working below, are very characteristic and, in some instances, extremely 

 beautiful. Not infrequently this insect breeds in such large numbers that the 

 bark is fairly dotted with its exit holes, while the tissues beneath are riddled 

 by numerous galleries of both adults and larvae, not to mention the borings 

 of young Monohammus larvae, frequently found in these situations. Later, 

 Rhagium and Pytho may occur, though as a rule, not so abundantly as under 

 the thicker bark at the base of the tree. 



The Balsam Bark-borer {Tomicus balsameus, Lee.) is another extremely 

 interesting species. It is occasionally quite injurious to its food plant. The 

 early work begins with an irregular central chamber with two or more 

 transverse adult galleries, the larval burrows being usually with the grain of 

 the wood. This insect breeds throughout the length of the tree and occasion- 

 ally a group of adults, starting from one central chamber, may entirely girdle 

 a young twig, though this method of work is somewhat exceptional. Three 

 transverse galleries originating from a central chamber is somewhat typical 

 of this insect's work. The plan of operation is frequently obscured in ti 

 badly infested tree by interlacing of the galleries and the development of 

 fungus in the decaying tissues. Under these conditions, the only evidence 

 we know of to show that the tree was attacked while alive is the occurrence, 

 in small chambers here and there, of masses of dried balsam. These 

 accumulations usually result from balsam flowing into cavities from injured 

 living tissue. 



It will be seen from the preceding that much can be learned from com- 

 paratively obscure signs when one understands their significance. The gal- 

 leries of various bark borers are so characteristic as to permit of the ready 

 identification of most species, and in not a few instances the determination 

 of the plant affected. Furthermore, the condition of the tree at the time 

 of attack can be determined with a considerable degree of confidence and 

 the sequence of the species ascertained. The same is true of insect work in 

 many other groups though it is not always so susceptible of proof. Many 

 times the signs have little or no significance because we fail to comprehend 

 their import. 



Records of insect work are sometimes made under other than natural 

 conditions. Certain species invade the house, and, unfortunately, many of 

 us are too familiar with signs of their presence. Occasionally^, as in the 

 instance under consideration, the insect is the sufferer. This particular 

 ease is of special interest, since it is practically an artificial fossil, a large 

 June beetle (Lachnosterna) having been literally crushed into the paper 

 during the process of calendaring. Note the preservation of the antennae 

 and legs, suggestive of what might be done along this line with other 

 species. Incidentally, we wish to call attention to the melancholy fact that 

 a few individuals, insect as well as human, attain notoriety only when they 

 make an exit from this world in an unusual manner. 



Turning now to some forms which are of great interest to residents of 

 cities and villages, allow me to give you a little idea of their importance in 

 an adjacent State. The work of the White Marked Tussock Moth 

 (Hemerocmnpa Icucostiqma, Sm. & Abb.) is so well known that we uncon- 

 sciously associate defoliated horsechestnut trees with the presence of this 



