33 



is enough difference between the valves of the European and Ottawa 

 specimens to be considered possibly of specific value, were it not for 

 the survival of the Alaska and British Columbia races; which are 

 intermediate. The European form has a rather simple lobate valve, 

 with a thickening of the chiten producing a small ridge and snKill 

 projection near the tip, (the cucuUus of Pierce). In the Alaska form 

 the ridge is somewhat longer, as is also the projection which is armed 

 with a definate spine at the tip, lacking in the European form, and 

 the valves also are somewhat more modified being considerably con- 

 stricted basally of the center. The British Columbia form merely 

 carries the same pattern a little further, altho the spine at the tip 

 of the projection is not as conspicuous, being somewhat flattened. 

 The Ottawa form has the valve-shape nearly as in the British Colum- 

 bia form, but the ridge and projection are considerably longer and 

 heavier, the latter armed with a rather heavy spine at the tip. 



To the Alaskan race, representing the extreme of variation in 

 American forms is given the name morrisoni, certainly racially dis- 

 tinct from the European and Eastern forms; in color and genitalia. 

 There is a very gradual gradation from the Eastern race, thru local 

 Alberta, Manitoba and California races to the British Columbia race. 

 It is considered best to fix no names to these, allowing them to stand 

 as intermediates. 



It is very probably that solidaginis spread from Europe into the 

 United States thru Siberia and Alaska in comparatively modern times, 

 geologically; in all probability since the Pleistocene glaciation, which 

 would account for the similarity of the races. 



The following synonomy is suggested, for the American lists: 



Lithomoia solidaginis solidaginis, Hbn., Europe, 

 race morrisoni, nov., Alaska. 



race germana, Morr. Eastern States to British Columbia. 

 Type localities and number and sexes of the types of morrisoni: $ Holo- 

 type and 1 $ Paratype, Chatanika; 9 Allotype and 1 9 Paratype, Chatanika; 

 1 9 Paratype, Ramparts, Aug. 1-7; all Alaska. 



XyLOTYPE ARCADIA, Sp. nOV. 



Ground color pale whitish-gray. T. a. line black, double, filled in with 

 white. T. p. and s. t. lines similar, the s. t. not plainly double, the white filling 

 mesad of black line being bordered by a few scattered black scales. Terminal 

 line composed of pale crescents edged outwardly with gray. Course of the basal, 



