Groups of the Lepidoptera. 341 
But of course it does not rest with me, or any follower 
of the Linnean order, to show M. Guenée how he may 
gratify his taste for tactical movements. M. Guenée had, 
before the new arrangement came out, done his best to 
condemn it by anticipation; for he had stated in the 
language I have quoted, that to place Geometra next to 
Bombyx would require a re-arrangement of the Noctue, 
though he has since fathered the proposition to carry out 
the innovation, and yet leave the Noctuce as they were. 
So much for the new arrangement. It was introduced 
in a List intended to catalogue synonyms, and the pro- 
mulgation of it seems to have been considered a minor 
object, even by its authors. In England alone does it 
appear to have taken root. No writer on the Continent 
follows the plan; and the Americans do not so much as 
recognise its existence. In Dr. Packard’s ‘‘ Guide to 
the Study of Insects,” one of the best entomological 
books ever written, the order of the Lepidoptera given is 
that of Linnzeus, and the work contains numerous pas- 
sages in support of that arrangement (see pp. 283-284, 
293, 302, 318, &c.). In the preface (p. iv.) we read that 
this succession of the families of the Lepidoptera is “that 
now generally agreed upon by entomologists.” It seems 
that lists without reasons are not accounted anything 
by the great nation beyond the Atlantic. 
One word before we come to the “ Lists,” upon the 
principle on which changes in names are to be made. 
It is continually being discovered that, after an insect 
has been called by one name for, say, fifty years, it really 
ought to be called something else, because that name 
was “earlier.” I leave out of the question the doubt 
which attends so many of these earlier names, arising 
from variable characters, imperfect condition of a speci- 
men, from mis-coloration of a figure, or lack of descriptive 
acumen in the author,—all matters affecting the fidelity 
of a reference. But, supposing a prior name to be dis- 
covered clearly meant for the insect which has always 
been misnamed; is it always desirable to discard the 
wrong name? It is a maxim of law, which might with 
advantage govern scientific nomenclature, that Com- 
munis error facit jus; and, when the entomological 
world is startled by receiving orders to call all the old 
insects by new names, | think a craving for some good 
rule of this kind must be experienced by many. It 
