1943] 
Nearctic Forms of Lycceides 
89 
midway between ar gyro gnomon and melissa — somewhat closer 
perhaps to the former than to the latter. 
The Lycceides variation in color and pattern as expressed in 
more or less constant races of each species can only be briefly 
alluded to here. Its scope in regard to the male upperside does 
not seem so wide in the American argyrognomon and scudderi 
as it is in the palearctic argyrognomon and cleobis, in both of 
which the upperside may be, racially, almost or totally devoid 
of optical scales, thus leaving the richly pigmented fuscous sur- 
face intact. In the nearctic groups, both in argyrognomon and 
in scudderi, the optical spread transcends at least the sub- 
terminal limit so that the insulae of the secondaries (the sil- 
houetted in fuscous pigment counterparts of the underside prae- 
terminal spots), if not circumviated more or less completely 
by the violet blue, are left sometimes encased in a slightly less 
compact fuscous which the eye sees as a thick, sometimes 
crenulated, “black border.” The effect of crenulation may be 
enhanced by the strong development of terminal triangles and 
cilian markings in both these species as well as in ismenias. 
In melissa the blue extends at least to the circumviating stage 
but more often swamps the insulae to reach a terminal limit 
(that last bulwark of tenuous fuscous which is not crossed in 
any Blue) so that on the upperside the male melissa may be 
said to be (as far as is known) the least variable of the poly- 
morphic Lycaeides species. 
On the underside, however, all three pass through a gamut 
of coloration just as wide as in the palearctic forms. Each of 
them goes racially from the nearest approach to the basic pig- 
mentation of the upper surface, namely from brown or brown- 
ish fawn, through fawn, pale fawn and greyish fawn, to greyish 
and almost pure white. If a combination of characters does 
not produce in both sexes some striking and constant aspect 
in a more or less extensive population, and insofar as tangible 
objects, and not ecological or other causalities, should receive 
systematic names, it seems to me quite useless to separate a 
series of, say, pale underside Yakima melissa from equally 
pale Nevada series, or a darkish underside Texas series from a 
similar one collected in Saskatchewan. 
The rhythms in the pigmentation of the spots, in the spread 
of the underside optical scaling and in the structure of the mar- 
