ONE HUNDRED THOUSAND FACTS FOR THE PEOPLE. 399 



CANKER-WORMS.— In illustration of 

 the remarks on the two species of Canker- 

 Worm which have very generally been 

 considered mere varieties of one species, 

 and about which there has been no little 

 confusion, we have prepared figures of 

 each, which, in connection with a few ex- 

 planatory remarks, will enable their ready 

 distinction. 



The Spring Canker-Worm. — This spe- 

 cies, which, from the fact that the great 

 bulk of the moths issue from the ground 

 in early spring, may be distinguished from 

 the other by the popular name here given, 

 is the true Can- 

 ker-Worm orig- 

 inally described. 

 This is undoubt- 

 edly the species 

 for the most 

 part spoken of 

 FlG - 4 1 - in the agricul- 



Spring Canker-Worm.— tural journals of 

 a, full grown larva; 6, egg. the countrV and 

 enlarged, the natural size ^e country , ana 

 shown in the small mass at 'he species best 

 side; c, an enlarged joint, side known in the 

 view; d, do., back view, Mississippi Val- 

 showing the markings. ^ This Spring 



Canker-Worm is distinguished, in the 

 light of recent careful discriminations, by 

 the characters following, viz.: by each of 

 the first seven joints of the abdomen in 

 both sexes bearing two transverse rows of 

 stiff, red, or reddish-brown, posteriorly di- 

 rected spines ; by the front wings in the 

 male having three transverse, dusky lines, 

 and a somewhat broader, jagged, pale 

 submarginal line ; and by the whole body 

 in the female, as also the legs and anten- 

 nae, being pubescent with pale and dusky 

 hairs — the color being rabbit-gray, or 

 speckled black and white, the abdomen 

 having a medio-dorsal black stripe. The 

 •dusky stripes on the front wings of the 

 male, except at costa, and the black stripe 

 •on the abdomen, except at each end, are 

 usually more or less obsolete, and indeed 

 the ornamentation of the wings is ex- 

 tremely variable. In many specimens the 

 middle portion of the front wings, within 

 the three dusky lines, is quite pale and 

 mottled with grayish-green, while the ba- 

 sal and terminal portions are marked with 

 brown, thus making the contrast greater.' 

 Others again are absolutely without marks 

 whatever, even when fresh from the chrys- 

 alis; while captured specimens always 



have the marks more or less effaced on 

 account of the looseness of the scales. 

 The moths rise from the ground, for the 

 most part, early in Spring, and only rarely 

 the previous Fall. They are crepuscular 

 in habit, and are most active soon after 

 dark in the evening. The female, by 

 means of a horny and extensile ovipositor, 

 thrusts her eggs, to the number of from 50 

 to 150, under the loose scales of bark or in 

 any crevice or sheltered place, and is very 

 fond of availing herself for this purpose 

 of the empty cases of the Rascal Leaf- 

 crumpler. The eggs are but slightly 

 glued together, and have the form of a 

 rather elongate hen's egg, the shell being 

 very delicate and smooth, though often 

 appearing roughened by transverse and 

 longitudinal, irregular depressions. The 

 larva has but four prolegs, is variable in 

 color, and one of its distinguishing char- 

 acters, is the mottled head and two pale 

 narrow lines along the middle of the 

 back, the space between them usually 

 dark and occupied on the anterior edge 

 and middle of joints by black marks 

 somewhat in form of X; these marks be- 

 ing represented by dots on the other 

 joints. There are two rather prominent 

 tubercles on top of the eleventh joint, 

 preceded by two white spots. The chrys- 

 alis, so far as our comparisons have ena- 

 bled us to judge, does not differ materi- 

 ally from that of the other species, so that 

 the two species could hardly be distin- 

 guished in this state. This is the species 

 which so injuriously affects our apple or- 

 chards. 



The Fall Canker-Worm. — This in- 

 sect is easily distinguished from the pre- 



Fig. 42. — Fall Canker-Worm. 

 a, b, egg, side and top views; c, d, joints of 

 larva, side and top views, showing markings — en- 

 larged ; e, batch of eggs ; /, full-grown larva ; g, 

 female chrysalis — natural size; h, top view of 

 anal tubercle of chrysalis, enlarged. 



ceding, when critically examined. It is, 

 on the average, somewhat larger and 



