242 WILLIAM T. M. FORBES 



Key to the species 



1. Base and costal edge whitish 5. cinereocostella. 



1. Base and costal edge not whitish. 

 2. With a pale fourth discal dot. 



3. Fourth discal dot white, conspicuous, and preceded by a long white line. 



7. emeritella. 

 3. Fourth discal dot less conspicuous, preceded by a heavy black bar. 



3. maculatella, 4. symmochlota. 



3. Fourth discal dot less conspicuous and not preceded by a longitudinal 

 bar. 



4. Hind wing whitish, much paler than fore wing (1.) togata. 



4. Hind wing light gray, paler at base 1. betulella. 



2. No pale fourth discal dot. 



3. A pale, acute-angled fascia 6. heracliana. 



3. No such fascia 2. grotella. 



1. D. betulella Busck. Fuscous, obscurely mottled, with the pale base of inner 

 margin most conspicuously contrasting; terminal dots present; black discal dots 

 obscure; head yellowish. 23 mm. 



Caterpillar in a silken tube between leaves of black birch; pale green with 

 black tubercles. Moth emerging in June. 



Vermont to Pennsylvania. 



D. togata Walsingham, described from the Rocky Mountain district, is closely 

 similar but with rather darker fore wings and paler hind wings. It may enter the 

 northern part of our territory northward, and has been reported from Vermont, 

 though apparently in error for the preceding species. 



2. D. grotella Robinson. Dull straw color, second joint of palpi blackish below; 

 fore wing nearly evenly colored, a little redder on the disc, with vague longitudinal 

 streaks of fuscous, the one in the outer part of the cell hardly more contrasting 

 than the rest, but present, the most distinct streaks being a postmedial series 

 between the veins. Fourth discal dot dark, terminal dots distinct; hind wing 

 pearl gray. 20 mm. 



Caterpillar green, darkest dorsally; cervical shield green, unmarked; head 

 green with a black dot on each side above the jaws; on Corylus. 

 This species is unknown to me. 

 North Atlantic States. New York (Robinson). 



3. D. maculatella Busck. Similar, crisply black-dusted on a chalk-white ground, 

 appearing light gray. Fore wing with fuscous streaks between the veins, more 

 or less interrupted by a faint, pale, dentate postmedial line; two pale discal dots, 

 with a heavy black bar in the cell between them, touching the first. 22 mm. 



New Hampshire and Connecticut to Ontario and western Pennsylvania. 



4. D. symmochlota Meyrick. Similar to D. maculatella, but ground mouse 

 gray or fuscous, with some pale shading and scaling, especially indicating the post- 

 medial line. Sparse black scaling on the dark portions. Bar in cell as in D. 

 maculatella, conspicuous. 20 mm. 



Late July to early August. Perhaps the same as D. grotella. 

 Sebec Lake, Maine; Parry Sound, Ontario; Manitoba. 



5. D. cinereocostella Clemens. Fore wing reddish-brown, marked with numerous 

 short black dashes; costa, head, and thorax normally much paler, whitish gray; 

 hind wing grayish fuscous. 18 mm. 



Occasionally the costa is practically concolorous with the rest of the wing, but 

 such specimens are recognizable by their pinkish tint, distinct pale postmedial 

 line of whitish scaling, minute or wanting fourth discal dot, and absence of any 

 blackish shading in the cell. 



Fresh moths occur in July The caterpillar is bright sulphur yellow with a 



