The Moths and Butterflies 397 



i.e., over 2 inches expanse, but most are of medium size, with white, deli- 

 cate green, soft yellowish, brownish, grayish, and blackish as predominating 

 color tones, and delicate wavy or zigzagging transverse lines, or point-like 

 spots as characteristic pattern markings. The superfamily is divided into 

 five families based on venational characters rather confusing and appar- 

 ently not surely indicative of natural relationships. We may content our- 



FIG. 568. Male and female lime-tree canker-moths, Hibernia tiliaria. (After Jordan 

 and Kellogg; twice natural size.) 



selves with brief reference to some of the more interesting, beautiful, or eco- 

 nomically important species. 



The best-known Geometrids of economic importance are the canker- 

 worms (Fig. 565), two species in particular, known as the spring canker- 

 worm (Paleacrita vernata) and the fall canker-worm (Anisopteryx pometaria), 

 being responsible for much damage to orchards, especially apple-orchards. 

 The females of the canker-worm moths are wingless and so have to climb 

 the trees to lay their eggs on the branches and twigs. 

 This fact naturally suggests the most effective remedy 

 for them, namely, banding the trees with tar (mixed 

 with oil to prevent its drying) so as to make effective 

 barriers against them as they crawl upward. Printers' FIG . 6Q 

 ink, refuse sorghum, or any slow-drying varnish is abortlvaria. (After 

 equally effective. From the eggs laid in the spring by Lugger; natural 

 Paleacrita and in the fall by Anisopteryx hatch active 

 little "loopers" which feed voraciously in the foliage. The eggs of the fall 

 canker-worm do not hatch until the following spring, just when the young 

 apple-leaves begin to unfold. The full-grown canker-worms are about i 

 inch long, greenish brown and striped longitudinally with pale yellow. 

 Some of these stripes are broad on the fall canker-worm; all are narrow 

 on the other species. When full grown the larvae crawl down the tree to the 

 ground, burrow into it and pupate in a thin silver cocoon. The males of both 

 species are winged delicate moths; Paleacrita has pale ash-colored or brownish- 

 gray, silky, almost transparent fore wings with four or five broken transverse ! 



