06 SECOND ANNUAL REPORT OF 



from such oversights, that paragraphs like the following take their 

 rise. This one may be found in the Boston Journal for may 23d, 

 1866: 



Origin of Canker-worms. — A Medford correspondent says that 

 last fall he applied to his trees protectors which were pronounced 

 the best in the neighborhood, and notwithstanding not a single grub 

 passed over them, the trees, like others in the vicinity, are this sea- 

 son covered with worms which are now pursuing their devastating 

 work. In his opinion the Canker-worms do not originate from the 

 grub, and he challenges proof that they do. The subject is one 

 worthy of investigation ! 



Whe-e-e-e-ou ! It needs no comments in this Report. 



When first hatched the young Canker-worms are of a dark olive-green or brown hue, with a 

 shiny black head and thoracic legs, with a whitish lateral and dorsal band, the latter having a 

 darker central line along it. After the first moult, the head becomes lighter and mottled, and the 

 light bands less conspicuous. After the second moult the bands are almost obliterated and the 

 body becomes more uniformly mottled and speckled with livid-brown ; the head becomes still 

 lighter and the prolegs being now large, spread out at almost a level with the venter. After the 

 third (and I believe last) moult the appearance changes but little. The full grown larva averages 

 0.90 inch in length with an average diameter of 0.10 inch, being broadest on joint 11. It varies 

 from light fleshy-gray to almost black. Head mottled as in Figure 67. Ends of body somewhat 

 darker than middle. Joint 1 with a yellowish dorsal shield, the hinder margin in form of a 

 rounded W. Viewed under a lens the body has a series of eight fine light yellowish, irregular, 

 somewhat broken lines, running the whole length of the body, each one relieved by a darker shado 

 each side of it. The two along middle of dorsum are close together, with the space between them 

 usually dark, and occupied at anterior edge and middle of joints 5, 6, 7 and 11 by black marks 

 somewhat in form of x, these marks being represented by simple black dots on the other joints. 

 .Space between these dorsal lines and the next lowest, lighter, and containing four black pilifer- 

 ous spots to each joint, the posterior ones rather further apart than the anterior ones which on joint 

 11 form two larger elevated shiny black spots. Space between lines 2 and 3 darker than any other 

 part of the body. That between lines 3 and 4 lighter than any other part of body and containing 

 the stigmata which are perfectly round and black with a light centre, with a small piliferous spot 

 anteriorly above and below them, and another behind them, this last becoming large on joints 5, 

 6, 7 and 8. Venter dark and livid at borders, with a pale greenish band along the middle, which lias a 

 pinkish patch in it on joints 5, 6, 7 and 8. Legs greenish at base, color of body at extremity. The 

 markings are most distinct on the light specimens. 



The Canker-worm is by no means confined, in its destructive 

 work, to the Apple, for it likewise attacks the Plum, the Cherry, the 

 Elm, and a variety of other trees. Mr. R. J. Mendenhall, of Minnea- 

 polis, Minn., even informs me, in a recent letter, that "the Currant 

 worm" spoken of in a late number of the Farmer's Union as infesting 

 the currant bushes in the gardens around that city, were really Can- 

 ker-worms, but he is most assuredly mistaken. The Canker-worm is 

 seldom ever noticed on our trees till the riddled and seared appear- 

 ance of the foliage tell of its presence ; for, like most other span- 

 worms, it has the habit of resting in a stiff straight posture, either 

 at an angle of about 45° from, or flat and parallel with the twig which 

 it occupies — thus eluding detection. 



After it has attained its full size it either crawls down the tree or 

 lets itself down by means, of a silken thread, and burrows into the 

 ground. Here, at a depth of two or three inches, it forms a rude co- 

 coon of particles of earth intermixed with silk (Fig. 66, d). Within 

 two days after completing the cocoon the worm becomes a chrysalis 



