[3]. It is not a caterpillar, but the pine-beetle, a tiny insect which burrows in the pith of the small twigs and kills them. The squirrel may eat the young tip or nibble the bark of a young twig, but he never bites the branch off.
“Pines and Pine-Beetles
“To the Editor of ‘The Times’
“Sir,—In your paper of Saturday, p. 13, under the heading of ‘Pines and Squirrels,’ your correspondent mentions that he believes I could probably give the history of the insect, which he notices the attacks of, as causing much injury to pine shoots, which injury is popularly ascribed to mischief caused by squirrels.
“From the main points of Mr. Stillman’s description it is presumable that this injury is caused by the infestation especially known as the ‘pine-beetle,’ the Hylurgus piniperda, scientifically. This beetle goes through its early life between the bark and wood of felled or sickly pines or fallen boughs, and when the beetles leave their place of development they fly to the shoots and tunnel them.
“Consequent on this injury a high wind brings them down in great numbers, and some may be recently tunnelled and still have the beetles within, or some may be of much older date.
“Without having a specimen I cannot speak with certainty, but the only point that differs in your correspondent’s description of the attack from that of the H. piniperda is his mention of the tunnelling being done by a grub. Should this not be from his own observation, but merely from the general appearance, I should say the damage was certainly that of ‘the pine-beetle.’—Yours, etc.,
“Eleanor A. Ormerod, F. E. S.”
“Torrington House, St. Albans, Sept. 19.”
[4]. This idea that a squirrel’s teeth grow too long from not gnawing hard food is, I think, a mistake, as Billy’s never grew beyond their proper form, nor did Hans’s. Billy used to sharpen his teeth by grinding them together. I have often heard the process going on as he lay by my ear on my pillow at night. The cases known of long teeth requiring cutting off were probably due to the breaking of the opposing tooth.