138 Psyche [Sept.-Dee. 
behind in the others, or it may attain a good average in most 
characters. Finally, “expression” means the slight differences 
by which even the most strikingly homoptic forms ( i.e ., belong- 
ing to different species) may be distinguished without an exam- 
ination of the genitalic structure. 
A priori , I had assumed that in the course of the combination 
and segregation of generic characters in various racial forms 
(and this is incidentally the meaning I attach to the term 
“form”) each of the six structurally different groups (i.e., spe- 
cies) of Ly oxides would be seen to repeat certain stages of the 
same general (i.e., generic) variation, but would reveal differ- 
ences in rhythm, scope, and expression, the total of which would 
produce the synthetic character of one species as differing from 
the synthetic character of another. This has proved correct 
insofar as the species are known at present, although certain 
aspects of rhythm are exaggerated or, inversely, blurred by 
erratic taxonomy and by the tendency to create a new form not 
because of its marking some important combinational stage in 
the morphologic development of the species, but because of its 
coming from some new locality. New localities, however, are 
most welcome in themselves, for it should not be forgotten that 
immense areas, practically all of European and Asiatic Russia, 
as well as China, and numerous more limited areas in the pale- 
arctic and nearctic regions are more or less terra incognita in 
regard to these butterflies (although no doubt much precious 
material from there lies unsorted or misidentified in museums), 
so that one can still hope to obtain an agnata with white under- 
side, a subsolanus as blue as melissa, and a melissa with a heavy 
vadum. 
In delineating in this manner the principles I intend to follow 
in my subsequent discussion of racial variation in Lycceides 
species, I am guided among other things by the belief that the 
systematist may fare better when keeping to the all important 
morphological moment, than when giving comprehensive geo- 
graphic names (the whole of China, the whole of the Moon) to 
hypothetical “populations” (a dreadfully misused term — and 
a hideous word, anyway) on the basis of half a dozen specimens 
taken by somebody between climb and cloud on some mountain 
thousands of miles away from the describer’s desk. 
