17 



very closely related in the structure of the Uncus and also in general 

 niaculation. The first two species have been listed respectively as a 

 synonym and a color form of cccrulata Fabr. {aiitumiialis Strom); 

 this species however scarcely occurs in North America (unless possibly 

 in Alaska) and our studies of the genitalia have shown us that the 

 forms of the Eastern States at present listed under this name may really 

 be readily separated into several distinct species. 



The two latter of the three species mentioned are apparently quite 

 rare and study of more material and especially of life histories may 

 cause some change in our grouping but for the present we list each as 

 a good species. 



Hydriomena frigidata W1U-. ( PI. Ill, Figs. 12-14 ; PI. X'lII, Fig. 5). 



The species, as already noted, is quite distinct from cccrulata 

 Fabr. ; it is a form of the early spring ( April-May) and can at once be 

 separated by its extremely dark secondaries which have the cross-line 

 only faintly developed ; the primaries are usually a deep blackish-green 

 crossed by a rather obscure median whitish band, a characteristic of 

 which appears to be that it shows distinct black shading below the discal 

 streak. The Uncus is bifurcate with long narrow neck, the bifurca- 

 tions forming more of a U than a V and being rather short and chunky. 



A form of what we believe to be this species occurs in Manitoba 

 and is characterized by the much whiter basal and median areas, the 

 latter still showing, however, the blackish suffusion below discal streak ; 

 the green of the ground-color is also rather paler ; we propose for this 

 race the name Manitoba, our types being 4 (J , 1 9 from Cartwright, 

 Man. (May 25 and 28). 



The typical form appears wide-spread in the Eastern and Middle 

 States ; we have seen specimens from New York and New Jersey and 

 have series from New Brighton, Pa. and Decatur, 111.; there is also 

 a single specimen in the American Museum from Blanco Co., Texas 

 and Mr. Swett tells us that a specimen mentioned by Packard from 

 Kentucky under calif oniiata (Monog. p. 95) is probably this species. 



Hydriomena transfigcrata Swett. (PI. Ill, Fig. 15). 



Through the kindness of Mr. Swett we possess a Co-type of this 

 species; as this is a unique specimen in our collection we have been 



