56 THE. REPORT OF THE No. 19 



FOREST INSECTS. 

 By Rev. Thomas W. Ftles, D.C.L., F.L.S., Levis, Que. 



Insects fall naturally under two heads. — biting insects, Mandibulata, 

 and sucking insects, Haustellata. To the former belong the borers in the 

 tree-trunks, the twig-girdlers, and the leaf devourers ; to the latter, the Cic- 

 adas, the scale insects, and the plant lice. It is difficult to tell which of the 

 two orders is the most hurtful to vegetation. In "God's great army" the 

 most insignificant corps becomes occasionally by force of numbers, a formid- 

 able array. 



In the summer of 1881, the maples presented a strange appearance. 

 Their foliage became brown and withered, as if autumn had come before its 

 time. On examination it was found that countless multitudes of the larvae 

 of a minute species of moth, Depressaria acerifoliella, had assailed the foliage. 



The larva of this species bites disks from the leaves and binds them to- 

 gether with a silken filament, so constructing a case for itself. It protrudes 

 its head and forelegs from its case and moves about the leaf, eating away the 

 fleshy parts. 



In 1893 another remarkable insect attack upon the maples was witnessed ; 

 nearly every leaf of the trees was drawn out of shape^its edges being fastened 

 together with a fine web. Within the tent thus formed was a curious brown 

 case, somewhat in the form of a cornucopia, and snugly ensconsed within the 

 case was a green larva with an amber-colored head. This truly was one of 

 the most economical of insects. Longfellow has said: — 



"O thou sculptor, painter, poet I 

 Take this lesson to thy heart : 

 That is best which lieth nearest, 

 Shape from it thy work of art." 



And this larva had used up its exuviae and excrement in forming a case for 

 itself — an inner retreat. The leaf was its shelter and store of food; for it fed 

 upon the parenchyma, and left only the veins and skin. The case was its 

 stronghold. The name of the insect is Semasia signatana. 



Our native insect pests are bad enough ; but the insect foes that we most 

 dread are the foreigners, for the reason that "it is better to deal with the 

 devil you know than the devil you don't know." 



The advent of the Larch Saw-fly (Nematus Ericlisonii) is an old story 

 now. This pest destroyed our tamaracs in the eighties, and it 



"Still goes marching on." 



Mr. A. H. D. Ross, in his excellent article on "The Forest Resources of Lab- 

 rador Peninsula," tells us that of late years the* European Larch Saw-fly has 

 destroyed inost of the larch between Lake St. John and Lake Mistassini. and 

 the pest is spreading northward. 



The Gypsy moth, the Brown-tail moth, and the Leopard moth are new 

 importations to the country to the south of us. 



So great a plague has the Gypsy moth been in Massachusetts that the 

 Legislature in four years (1890-4) expended |275,000 in the effort to extermin- 

 ate it, and had not succeeded ; and further appropriations were* required. 



The larva of the Brown-tail moth is also injurious in Massachusetts, and 

 as their fine barbed hairs are easily detached and carried in the air, they often 

 settle upon the passers-by, work their way into the pores of the skin and cause 

 much suffering. They are greatly to be dreaded. 



