The Moths of the British Isles Second Series/Chapter 13



Of the eighty-six Palæarctic species referred to this family, by far the larger number are eastern, only about eight appear to be found in Europe, and but three of these occur in Britain.

Meyrick separates Cossus cossus (ligniperda) from our other two species, adopts Trypanus, Rambur, as the generic name, and removes it to the Tortricina as a family of that group under the name Trypanidæ.

The English name of this species (Plate 150, Figs. 1 ♂, 2 ♀) applies more especially to the caterpillar, as this creature gives off an odour which has been compared to that of the he-goat. In general colour the caterpillar is pinkish ochreous, inclining to dark reddish on the back; the small head is black and glossy, and the mark on the first ring of the body is black. It feeds in the solid wood of various trees, especially elm, ash, and willow, but is three or four years in completing growth. When mature, it often leaves its burrow and wanders in search of a suitable place for pupation. When met with at such times it should be, if taken, placed in a roomy tin box with a good supply of sawdust or decayed wood, when it will make its cocoon, and appear as a moth in due course. The early stages are shown on Plate 151.

Caterpillars are more likely to come under the notice of the country rambler than are the moths; examples of the latter, however, may be seen occasionally, in June or July, resting on a tree-trunk, a fence, or a gate post; sometimes, although practically tongueless, the moth visits the sugar patch and either settles on the tree or flutters around.

The species seems to occur in all parts of the British Isles, except perhaps the extreme north of Scotland and the Hebrides.

Abroad, the range extends to Amurland and to North-west Africa.

As will be seen from the portraits of this blue-black spotted white species on Plate 153, the male (Fig. 6) is smaller than the female (Fig. 7); it will be further noted that the antennæ of the male are bi-pectinated on the basal half, and thread-like on the outer half; the antennæ of the female are thread-like throughout.

The caterpillar (Plate 152, Fig. 1, from a coloured drawing by Mr. A. Sich) is dull whitish, more or less tinged with yellow; the spots are black, and the head and plates on the first and last rings of the body are blackish brown. It feeds in branches and stems of trees and shrubs. Hatching from the egg, say in the late summer of 1908, the caterpillar will not be full grown until May or June of 1910, or possibly 1911; forming a cocoon of silk and wood particles, it turns to a reddish brown chrysalis in the burrow, and near the bark of the stem or branch. The moth comes out in the summer, and is most often seen in the London district, where the female especially is not infrequently found on tree-trunks or on grass, etc., under trees. It visits light, and the electric arc lamps are very attractive to it.

The species occurs in the south and east of England, and through the north-west counties to Cheshire. It has been recorded from Cardiff, South Wales, and doubtfully from Ireland.

Abroad, the range extends to Corea and Japan. In America it seems to be established in parts of the State of New York.

A male of this species (Macrogaster arundinis of some authors) is shown on Plate 153, Fig. 3. The female is rather larger, with longer body, and the antennæ are without pectinations.

The wrinkled and rather shining caterpillar is ochreous white with reddish-brown stripes along the back. It feeds low down on the stems of reed (Phragmites communis) and is full grown in the spring of the second year following that in which it left the egg in late summer. Thus, a caterpillar hatching in August, 1908, would be mature about May, 1910, pupate in that month, or the next, and the perfect insect would appear in June or July.

The moth flies at night, and may be attracted by a brilliant light. The earliest known British locality for the species was Holme Fen in Huntingdonshire (1841-1848). In 1850 it was found abundantly at Whittlesea Mere. Its haunts in the present day are Wicken and Chippenham fens in Cambridgeshire, but specimens from these localities are somewhat smaller than the old Hunts examples. Barrett states that he put down some eggs of the species in Ranworth Fen, Norfolk, and that five years later two males were captured within a short distance of the spot where the eggs had been placed.

The range abroad extends to China and Japan.