NORTH AMERICAN EUCOSMINAE. 89 



1918, 1916, C. N. Ainslie") which I take to be a local race of argen- 

 tialbana. There is little in general appearance to distinguish the 

 adults except their size which averages smaller (12 to 14 mm.) than 

 that of argentialbana but there is an appreciable though slight dif- 

 ference in their male genitalia. 



Those of argentialbana have the rudimentary uncus notched and 

 nearly square while the variety shows it triangular and pointed. It 

 is possible that these specimens may represent a distinct species but 

 for the present I prefer to leave them as an unnamed race of argen- 

 tialbana. There is also in the National Museum a series of half a 

 dozen moths collected at Florisant, Colorado, by S. A. Eohwer, July 

 7, 1907, in which the ground color of the fore wing is darker and 

 the white pattern is more outstanding than in what is generally un- 

 derstood to be the typical argentialbana. These moths in superficial 

 appearance resemble much more closely serpentana Walsingham, for 

 which they might easily be mistaken. One specimen of the series 

 has, indeed, been labeled by Kearfott as '"'' serpentana Walsingham 

 var." Their genitalia characters however are those of argentialbana. 

 I consider this also merely a variety and am leaving it unnamed. 

 This and the following three species are variable in both pattern and 

 structure and their races seem to run into each other so that it is 

 often difficult to separate them. I would also call attention to 

 three specimens from Verdi, Nevada, found among Kearfott's dupli- 

 cates — and which I take to be only a local race of argentialbana^ 

 larger in size (22 mm.) and with somewhat darker hind wings 

 and showing aberrations in venation; one specimen having 3-4 

 of fore wing approximate at termen and two with 3-4 of fore wing 

 fusing before termen. The venation of the hind wing also varies in 

 the three specimens. In one 3-4 is long stalked (differing in the 

 length of stalk in the right and left hind wing) and in the other two 

 they are united. For obvious reasons I am not naming this form. 

 I call attention to the aberations simply because in two other species 

 of the genus Eucosma {catacylstiana Walker and fioridana Kear- 

 fott) the fusion of veins 3 and 4 of fore wing before termen is a 

 constant character and would suggest generic separation were it not 

 for such intermediate forms as we find associated with argentialbana. 

 How many species we really have and what their exact limits are 

 we can only determine when their food plants and life histories are 

 known. 



Male genitalia figured from specimen in National Collection taken 

 in Colorado ("#2143"). 



Distribution according to specimens in National Collection, Amer- 

 ican Museum, and collection Barnes : Montana, Colorado, New Mex- 

 ico, Manitoba, Utah. 



