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A. W. LINDSEY 
was long- accepted as sufficient, but increasing inquiry into phylo- 
genetic relationships has shown that with such an arrange- 
ment forms of indubitably different value are often accorded 
the same rank. 
Some writers deny the right of the original specific name to 
stand alone if any named variations exist.^ This makes neces- 
sary the use of a trinomial for the correct designation of any 
form of a variable species. The following paragraph by Hartert, 
Jourdain, Ticehurst and Witherby® is pertinent in this connec- 
tion : “As the use of trinomials for subspecies — or better, geo- 
graphical or local races — does not seem to be generally under- 
stood, it may be here explained that when a species is divided into 
two or more races, or when two or more species are grouped as 
races of one species, then each of these races must have a tri- 
nomial appellation. It is impossible to say which is the oldest 
or parent form, therefore the first named race of all those grouped 
under one species is arbitrarily taken as the typical race, and its 
name becomes that of the species.’’ 
Other writers have adopted a very logically conceived division 
of the variations into forms and geographical races, a method 
of subdivision which was very successfully employed in the most 
recent check list of North American Lepidoptera.® In this list 
Dr. McDunnough also drew on the work of Mr. Roger Verity^^ 
for another form of subdivision, the seasonal generation, exempli- 
fied in Pieris napi Linn. This species is listed in our fauna with 
seven races, two of which are accompanied by named aestival 
generations, and in addition to these seven, three vernal genera- 
tions with accompanying aestival generations. According to the 
lettering used, the vernal generations are ranked with the races. 
This method of division, though it undoubtedly has its faults, ap- 
pears to be by far the most accurate indication of phylogenetic 
relationships yet devised for expression in a linear series. We 
must recognize the existence of geographical races, of which an 
excellent example, based largely on genitalic structure, is found 
in Hesperia tessellata race occidentalis Skinner.^^ Likewise the 
existence of seasonal generations has been proved beyond doubt, 
In Lepidoptera. see Rothschild & Jordan, Revision of the Sphingidae. 
* A Hand-List of British Birds, pp. ix-x, 1912. 
® Barnes & McDunnough, Check List of the Lepidoptera of Boreal Amer- 
ica, 1917. 
Verity, Rhopalocera Palearctica. 
” Barnes & Lindsey, Ent. News xxxii, 79-80, 1921. 
