18 
Grt., a “ representative ” species of the European JV. rwéz. I had no 
European examples with which to compare, and called the American 
specimens in 1874 ‘‘conjlua,” according to Mr. Smith’s determination 
of my examples in the British Museum. On the other hand, /e7- 
conflua, Grt., is the true American representative of confiwa, which 
latter is not found in America. My name /erconflwa, however, must 
go down before Mr. Walker’s jucunda. (2) “ Agrotis chardinyt,”— 
the reference of my gz/wipennis to chardinyt was made by Morrison. I 
had not compared the two, and Mr. J. B. Smith restores my name 
after examining material in the British Museum. When two Lepi- 
dopterists fall out, in America at least, they refer each other’s species 
as synonyms upon the slightest provocation. (3) Mr. J. B. Smith, in 
1882, under the name of Heliothis dipsaceous (and this peculiar: 
spelling is repeated in the Cad¢alogue), identified my phlogophagus, 
as identical with the European species; he afterwards, however, 
made them representative species. . (4) Zieniocampa tncerta.—The 
American specimens are considered to belong to a different species, viz. 
T. alia, Guen., by Mr. J. B. Smith ; consequently this is a case of a 
“representative,” and not of an “identical” species. I had followed 
Fitch in considering it identical, not having compared it myself. 
Other than these the determinations in Mr. Tutt’s pamphlet remain 
uncontradicted by more recent observations. 
When species ‘‘ agree exactly” they are ‘identical ;” when they 
“ differ constantly,” or their “normal condition” is to offer a slight 
change in colour, or marking, or structure, they are “ representative ” 
when inhabiting distinct geographical areas. 
The fact that these ‘‘ representative ” species, if not occurring on 
separate continents and inhabiting distinct areas, would be held as 
“parallel” species, shows that the characters by which they differ are 
of the kind we are accustomed to in closely allied species. They 
differ as do Phalera bucephala and P. bucephaloides, or Coremia 
Jerrugata and C. unidentaria, &c., in the nearest cases. But in 
America they shade off very gradually into the class of perfectly 
distinct species, the resemblance becomes always more vague and 
general ; so that we see that we have not to do with a sharply defined 
class of species, contrasting with the rest of the American Noctuids as 
a whole. As it is not always easy to separate the identical from the 
representative species, so also it is often difficult to say whether a 
species is representative or simply parallel. ‘The common origin of 
the North American and European fauna is at once evidenced by 
this fact. But in the “representative” species the resemblance is 
often so close, that we must seek some explanation. Why have some 
species (not introduced by commerce), such as Scoliopteryx lbatrix, 
remained unaltered, and others changed a very little? Why, out of 
all our many Apatelas or Catocalas, are there no identical, but several 
“representative” species? Now here is my theory: that these 
“representative ” species were once identical species, and lived on 
common ground before the Ice Age. If we accept this as a 
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