V —OLASSIFICATI ON, NOMENCLATURE AND REMARKS. 20 
difficulties which they will encounter in apprehending some 
of the species named and described by medern systematists. 
The frequent changes made in the nomenclature of 
species and genera of Lepidoptera often prove a serious 
obstacle to the student, but unfortunately such changes 
are usually unavoidable. This was very clearly explained 
by Dr. Longstaff* as follows:—‘‘ Here I would put in a 
word of encouragement to those who, like myself, are not 
systematists, and are, naturally enough, much put out by 
the changes of nomenclature that are nowadays so frequent. 
The value of a generic name is comparatively small, since 
genera correspond to the views of naturalists rather than to 
the facts of nature, and with increasing knowledge the views 
of naturalists change rapidly. Some divergences of opinion 
are due to the recognition, or otherwise, of the genera 
founded by older authors, which may, or may not, comply 
with our rules of nomenclature. Sometimes it is discovered 
that the author’s type of the genus was a species now recog- 
nised as very different in structure from the others included 
with it. Sometimes a familiar old name is dropped because 
the type species is clearly congeneric with some earlicr- 
deseribed species. Many changes which seem from a New 
Zealand or an English point of view to be meaningless are 
clearly comprehensible when a large fauna is reviewed. In 
short, generic names have changed, and, troublesome though 
it be, probably will change again. 
‘‘ With species, however, the case is quite different. 
They correspond with natural facts. There will probably 
always be both the ‘ splitter ’ and the ‘ lumper.’ Neverthe- 
less, while it is comparatively unimportant what generic 
name you use, it is most important, so far as possible, that 
all should agree as to the specific name. It is, for example, 
inost important that you should all mean the same thing by 
vitiosa Butl., but it matters comparatively little whether 
you include it in Melanchra or Morrisona.’’ 
I may add that, in my opinion, when any name has 
been in use for over fifty years, and is consequently men- 
tioned in much literature, it is very undesirable to alter it. 
Unless the resuscitation of a long forgotten name serves 
some definite purpose, the name which has been fifty years 
in general use should be retained. 
In employing this book for identifying species, the be- 
ginner is recommended first to consult the Plates and sce 
if he can find anything at all resembling the species he has, 
and then to refer to the description for verification. In 
dealing with variable forms, it is always well to remember 
that the shape of markings is generally far more constant 
than their intensity, or even their colour. 
The purely descriptive portions of the work have been 
made as brief as possible, but those who desire fuller de- 
tails may readily obtain them by looking up the original 
descriptions, which, as far as possible, are referred to under 
the synonomy of each species. 

*Trans. N.Z. Inst., XLIV., 108. 
It should be mentioned that the figures and deserip- 
tions in this work have been prepared from nature, inde- 
pendently. This course has been followed so that any 
character, which may have been omitted from the figure, 
will not necessarily be wanting in the description. 
The figures of neuration (Plates A—K.) have all been 
made from fully denuded specimens examined under the 
microscope. They are in nearly every instance considerably 
enlarged. Each drawing has afterwards been compared 
with Mr. Meyrick’s description, and if found to differ, a 
second examination of the wings has been made with a view 
of obtaining a reconciliation of results. This, in the great 
majority of cases, has been arrived at. 
The figures on the coloured plates have, as far as pos- 
sible, been taken from the finest and most distinctly marked 
specimens obtainable. In those cases where the necessary 
details could be clearly shown the figures have been drawn 
to life size, but in other cases they have been enlarged. No 
attempt has been made to draw the enlarged figures to any 
definite scale, the amount of enlargement necessarily de- 
pending on the size of the insect, the breadth of the wings, 
and the complexity of the markings. In every enlarged 
figure the average expanse of the wings, when fully ex- 
tended, is indicated by a line beneath each figure.* 
The figures of larvae and pupae (Plates I-III.) have 
been taken from living specimens, and those of eggs 
(Frontispiece) from examples recently deposited. 
The times of appearance, given under the heading of 
each species, cover the period during which the perfect 
insect may be observed freely on the wing. In the ease 
of the commoner species, stragglers have not! been taken 
into consideration, but with the rarer species it has often 
been necessary to simply summarize every authentic cap- 
ture. In some cases there has been a little difficulty in re- 
conciling the dates given by different observers, and ap- 
parently the period during which species may be observed 
is longer in the extreme south than elsewhere. The record 
of separate observations, in different localities, would have 
extended this portion of the subject beyond manageable 
limits, and in difficult cases an effort has been made to fix 
a good average period, during which the species may be 
looked for. 
Although the information given in respect of the 
localities and times of appearance of the various species is 
much more complete than formerly, owing to the greatly 
inereased number of collectors and observers, the records 
available must still be largely influenced by the habits and 
locations of individual workers. In connection with loeali- 
ties, it should be pointed out that some species, which are 
confined to the mountains in the North Island and northern 
portions of the South Island, descend to the sea level in 
the extreme south. 


*During the process of reproduction a very slight reduction 
has been made in the dimensions of some of the plates. This 
has resulted in some of the life-size figures being a little below 
the average in size, and the same slight variation may apply to 
the scale in respect of the enlarged figures. 

