322 EEPOKT OF TUE C0MMISSI0NE1£ OF AGRICULTUKE. 



Possibly 10 per cent, of our jSTortliern larches died from tlie attacks of 

 this worm. Very probably tLc numbers of this insect will diminisli 

 during tlie next year, and the species may ultimately become as rare as 

 it has always I'cen in Europe, until a decrease in its natural insect para- 

 sites and favorable climatic causes induce its undue multiplication." 



The foregoing prediction has been almost fully verified during the 

 past summer, as the insect has been much scarcer than in ISSi. A 

 few were seen on the larch in Cruuswick, ^lo., in July, 1885, but they 

 were not numerous enough to do any harm, and I have not heard of 

 rheir devastations in any part of Maine. The same ai)pcars to have 

 incn the case in the Adirondack region of New York. Mr. George 

 Hunt, who passed the summer at Scroon Lake, tells me that he saw 

 very few of the worms during the past summer, and he judged that 

 they had not been generally so destructive as the year preceding. As 

 tlie result of their ravages during tlie preceding years, he thought that 

 about one-third of the larch trees had died. It would seem as if the 

 visitations of the worm were over, and that for some years to como it 

 would be a rare insect, existing within its usual or normal limits. 



THE WHITE PINE WEEVIL, AND ITS INJURY TO SHADE* AND FOREST 



TREES. 



(Plssodes strohi Peck.) 

 [Plate IX.] 



For many years past our attention has been drawn to the deformities 

 I)roduced in forest trees by this beetle, as well as the injury it commits 

 in plantations and to ornamental trees on lawns and about houses. 



Dr. Fitch has already outlined the natural history of the insecc in his 

 fourth report. We have not yet been able to detect the beetle in the 

 act of eggdaying. Fitch says that the weevil deposits her eggs in the 

 bark of the topmost shoot of the tree, dropping one in a place at irreg- 

 ular intervals through its whole length. " The worm which hatches 

 from these eggs eats its way inwards and obliquely downwards till it 

 reaches the i)ith, in which it mines its burrow onwards a short distance 

 farther, the whole length of its track being only about half an inch. 

 But such a number of young weevils are usually placed in the aflfected 

 shoots that many of them are cramped and discommoded for want of 

 room. The worm on approaching the pith often finds there is another 

 worm there, occupying the very spot to which he wished to penetrate. 

 He thereupon, to avoid intrusion ui)on his neighbor, turns downward 

 and completes his burrow in the wood, outside of the pith. Those, also, 

 which enter the pith are often unable to extend their galleries so far as 

 is their custom without running into those of others. When its onward 

 course is thus arrested, the worm feeds upon the walls of its bun-ow 

 uiitil it obtains the amount of nutriment it requires and is grown to its 

 fall size." 



The eggs of this species are jirobably similar in shape, but consider- 

 ably larger than those deposited by the timber beetles, whose eggs and 

 larval development are figured and described in the Third Iveport of 

 the United States Entomological Commission (p. 280, Plate XXI 1, 

 Figs. 1, 8, 9, 10), According to Eatzeburg, the European P. noiatns 

 lays its eggs in the lower internodes of young plants, boring into the 

 sap wood with its beak. Its habits thus differ much from our si)eci(;s, 

 and it does not seem to afiect the terminal shoot. The grub or larva 

 does not differ from those of other borers found in the pine, as there is 



