In describing a moth various markings, etc., have to be referred to, and as
it may assist the reader more easily to locate the usual position of such
characters the accompanying diagram has been prepared. The lines crossing
the fore wings from the front edge, or margin (_costa_), to the inner edge,
or margin (_dorsum_), are generally styled transverse lines; the short one
is the basal; the first long one is the inner, or antemedial; the second is
the outer, or postmedial; and the third is the submarginal, or subterminal.
The whole wing, less the margins, is sometimes called the disc; but it is
more convenient to divide the fore wing into three parts, naming that
between the base of the wing and the first line the basal area; the space
between the first and second lines the central or median area, and the part
beyond the second line the outer area. The more or less round or oval rings
or dashes on {6} the central area are the stigmata, and these characters
occur more especially in the Noctuidæ. The hind wings usually have a fine
short line, crescent, or spot, at the end of the cell, as in the
butterflies, and there is generally a line or band beyond.
Immediately behind the head and covering the front part of the thorax is a
tippet-like arrangement of scales; this is the collar. On each side of the
thorax there is a shoulder lappet (_patagium_) which has its base on the
front part of the thorax also. Both tippet and lappet are often peculiarly
ornamented, and the former is sometimes strikingly coloured. The thorax is
sometimes crested, and more frequently the body is furnished with tufts of
erect hair scales.
The number of moths occurring in the British Islands is well over two
thousand. The majority of these hardly ever find favour with the collector.
This is probably owing in a large measure to the fact that they belong to a
division of the moth tribe which has been dubbed Micro-lepidoptera. It
happens, however, that quite a number of the species included in that
division are actually larger than many kinds that were placed in the other
contingent styled Macro-lepidoptera. According to the most recent
authorities the division of moths into two such main groups as those
adverted to is entirely fictitious and misleading. Possibly, when this new
order of things is more generally understood the so-called "Micros" will
receive their proper share of attention.
In the older systems of classification the Clear wings (Sesiidæ) were
associated with the Hawk-moths (Sphingidæ), but the former family is now
considered to be more closely connected with the Tineidæ. The Goat-moth
(_Cossus ligniperda_) has been removed from among the Bombyces, its name
changed to _Trypanus cossus_, and placed in the family Trypanidæ, which is
relegated to the neighbourhood of the Tortricidæ. The Burnets (Zygænidæ),
together with _Heterogenea limacodes_ and _H. asella_ (Cochliopodidæ), also
_Macrogaster castaneæ_ and _Zeuzera pyrina_ (Cossidæ {7} part) are removed
by Meyrick to the Psychina, a group placed between that author's Pyralidina
and Tortricina. The Swifts (Hepialidæ) are grouped with Micropterygidæ,
which are considered to be primitive forms of Lepidoptera originating in
the Caddis-flies or Trichoptera--a division of the Order Neuroptera.
Except that the Cymbidæ and Arctiidæ are placed just before the Noctuidæ
instead of after the Geometridæ, the arrangement of families, genera, and
species adopted in the present work is very much the same as that in the
1901 edition of Staudinger's Catalogue. Many British entomologists are now
interested in the lepidopterous insects of the Palæarctic, or at least the
European, fauna, of which our islands furnish but a relatively small number
of species. Others, who at the present time are perhaps but beginners, may
very possibly desire, later on, to extend their collections and their
knowledge by making entomological expeditions to various parts of the
continent. It seemed therefore desirable that in an introductory book on
British moths its method of arrangement should at least be founded on some
generally accepted system. {8}