Volume 1

A history of British moths / by F.O. Morris.

  • Francis Orpen Morris
Date:
1903
Catalogue details

Licence: In copyright

Credit: A history of British moths / by F.O. Morris. Source: Wellcome Collection.

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    nervures, is called the discoidal cell; it is sometimes divided into anterior, middle, and posterior discoidal cells. In some genera the transverse nervule is wanting between nervules 4 and 5, so that the discoidal cell is open, and con- tinuous with cell 4. There are also often small closed cells upon the discoidal cell, called accessory cells. Sometimes these are at the base of the hind wings in front, or when the discoidal cell is divided, they are placed externally between the two divisions, on account of the bisecting nervure forking on the basal side. In other cases they are placed, on the fore wings, at the anterior angle of the discoidal cell, where they are formed by the junction or crossing of two nervures, but generally through one branch sending off a nervule to the next. Cells thus formed are called appendicular cells. In the Tineae with lanceolate hind wings, the arrange- ment of the nervures is simplified. The discoidal cell becomes less distinct or completely disappears, as all the ner- vures arise from the base, or from other nervures. The number of nervures is also reduced in these moths, especially in the hind wings. The surface of the wings is divided longitudinally into three areas: basal, central, and marginal. In many genera these areas are marked on the fore wings with simple, double, or multiple transverse lines, which are often filled in or bordered with lighter, and are called the anterior and posterior trans- verse lines, or simply the first and second transverse lines. These are most typically present in many of the Noctuae, and form part of what is called the Noctua-pattern. The posterior transverse line is by some authors called the elbowed line. There is also frequently a short line on the costa, nearer the base, which does not reach the inner margin, and is called the half line. Besides this there is another line towards the hind margin, known as the submarginal line. Resting on the inner side of the sub- marginal line, we often find several black sagittate spots, pointing towards the base. There are also three marks, called stigmata, forming part of the Noctua-pattern. One of these, usually hollow, is situated on the anterior transverse line, in cell 16, and is called the claviform stigma; a smaller one, usually round, is placed in the discoidal cell, and is called the orbicular stigma; the third, which is situated behind the orbicular, is larger, elongated, and rests upon the transverse nervule; from its usual shape this is called the reniform Fig. 3.