CANKER WORMS. 783 



usually with brown and white or gray scales. A black or dark 

 brown stripe extends longitudinally along the back. Abdomen 

 tapering and terminating in a two- jointed ovipositor, which can be 

 exserted and is rather conspicuous. Wingless. 



Fall Canker Worm, Alsophila pometaria Harris. 



Egg. Shaped like a truncated cone, fastened endwise to the 

 tree or object, with the thicker end outward and marked with a 

 dark spot in the center and a dark circle near the margin. The 

 eggs are deposited in rows, in compact clusters of between fifty 

 and three- hundred eggs each (averaging about one hundred), 

 and are usually laid on the bark of the smaller branches, but may 

 be found on the trunk, or even on fences or stones. When 

 sticky bands are employed, the eggs are laid sometimes on the 

 band itself or on the bark of the trunk just below the band. In 

 color the eggs are brownish gray, but somewhat darker than those 

 of the spring species. On hatching, the young larvje emerge 

 from the outer end of the eggs, leaving a round hole about the 

 size of the circular ring. Egg-masses are shown on Plate XLIV. 



Larva or Caterpillar. Pale olive green at first, with pale head ; 

 later a dark gray or brownish form is often found together with 

 the light green caterpillars, both of which are similarly striped 

 with whitish lines. Both forms emerge from the same mass 

 of eggs. A pair of pro-legs is borne on the eighth segment, 

 making in all three pairs of pro-legs. The head is dark and 

 indistinctly spotted. About three- fourths or seven-eighths of an 

 inch long when fully grown. Caterpillars are shown on various 

 food plants on Plates XLV and XLyi. 



Pupa or Chrysalis. Somewhat stouter or broader and darker 

 brown than in the spring species. Male wing-sheaths reaching to 

 the sixth abdominal segment. Apex more blunt than in vernata, 

 and the spine decurved and always forked. About 7 mm. in length. 

 Not pitted. Enclosed in a rather strong silken cocoon interwoven 

 with particles of soil, making a cell that is not easily crushed. 

 See Plate XLIX b. 

 Imago or Adult Moth. 



Male. Wing expanse of from one to one and one-fourth 

 inches. Brownish gray in color, with a slight purplish reflection. 

 Antennae with over fifty joints, the length of the longest being 



