64 THE CANADIAN ENTOMOLOGIST 
of the cell and of cell 1st M2; cross- vein m connects M1+2 with 
J/3, weak and tending to atrophy; Cm leaves Ah before mid- 
length of the long cell 1st M-i. 
Abdomen elongated, tergites dark brown, the caudal margins 
of the segments narrowly paler; basal sternites more yellowish 
than the terminal segments; hypop^^gium brown. 
Habitat. — Alaska. 
Holotype, &, Sitka, Alaska; June 16, 1899 (Kincaid). 
Allotype, 9 , Saldovia, Alaska; July 21, 1899 (Kincaid). 
Paratypes, cf 9 , Yakutat, Alaska; June 21, 1899 (Kincaid): 
&, Virgin's Bay, Alaska, June 26, 1899 (Kincaid); cf, Saldovia, 
Alaska, July 21, 1899 (Kincaid). 
The type is in the collection of the United States National 
Museum; the species is based on material taken on the Harriman 
Expedition, and was determined by Coquillett as being T. debilis 
Will. 
The species agrees with debilis in many respects, but the general 
coloration is dark brown, not yellow; the basal segments of the 
antennae are not reddish and the venation is different, the cells 
1st M2 and Ml being greatly elongated. The abdomen and 
halteres are longer than is usual in this group of the genus. 
GEOMETRID NOTES. 
The Genus Dysstroma Hubner. 
BY L. W, SWETT, west SOMERVILLE, MASS. 
The genus Dysstroma Hiib. (Verz. p. 333, 1825) with its 
type trimcata Hufn. seems to be a natural group by itself. Hulst 
(Trans. Am. Ent. Soc, vol. XXIII, p. 283, 1896) under Hydriomena, 
cites trtincata Hufn. as the type of Dysstroma. Warren and 
Hampson both refer the trimcata group to Polyphasia Stephens, but 
treat it as a separate genus (Proc. Zool. Soc, p. 373, 1893, and 
Ind. Moths, III, p. 378). Mr. L. B. Prout points out in Trans. 
London Ent. Soc, part XVIII, p. 33, 1908, that /'o/v/?//a.y/a cannot 
hold, as Hiibner's name Dysstroma has priority. According to 
Mr. Prout's and my own views, what we have been calling trimcata 
in North America is really citrata Linne ("Fauna Suecica," ed. II, 
p. 332, 1761). 
February, 1917 
