August Thorn (Ennomos quercinaria).
The male (Plate [109], Fig. 2) is generally yellower than the female (Fig. 4), and it is in the former sex that brownish or red-brown clouding on the outer area beyond the second cross line appears most frequently, but it occurs also in the female (Plate [109], Fig. 5). Sometimes the wings are partly or entirely dull reddish brown. Two other examples of the type form showing modification of the cross lines will be found on Plate [111], Figs. 5 ♂, 6 ♀. In ab. carpinaria, Hübner, the wings are of a reddish ochreous colour. A hybrid resulting from a crossing of E. alniaria ♂ and E. quercinaria ♀ has been named dartfordi, Tutt.
The caterpillar (Plate [113], Fig. 3) is generally grey brown, mottled with reddish or olive; but, according to Fenn, it is
sometimes greenish, without humps or projections. It feeds, in the summer, on lime, birch, oak, hawthorn, etc. A chrysalis which I took out of its puparium (two leaves spun together with silk) on July 9, 1907, was green, with the upper surface tinged with yellowish; a dark-green central line, and a series of dark-green irregular marks on each side; the tail pointed and furnished with reddish hooks.
The moth is out in August and September, and may often be seen sitting on the boles of trees, generally low down. The species is widely distributed over England, but is much more frequent in the south than in the north. It has been recorded from Swansea in Wales; from Dumfries, Dunoon, and Monteith, in Scotland; and from near Derry, Hazlewood (Sligo), Mote Park (Roscommon), and Clonbrock (Galway), in Ireland.
Canary-shouldered Thorn (Ennomos alniaria).
This species (Plate [111], Figs. 1, 2) is generally easily recognised by the canary yellow coloured hairs of the thorax. The fore wings are yellowish, sprinkled with purplish grey, and crossed by two curved greyish-brown lines, which not infrequently fall close together on the inner margin. In some female specimens that I reared from eggs, received from York, the wings are more or less tinged with dull tawny brown, especially on the outer area, and in two of them the thorax is also brownish tinged.
The at first green, and afterwards blackish slate-coloured, egg, with whitish ring, and the caterpillar are shown on Plate [110], Fig. 2, 2a. The latter is brownish, mottled with purplish above, and inclining to greenish below; head, rather paler brown. It feeds, from May to July, on birch, alder, etc. The moth is out in the autumn, and occurs in suitable woodland and marshy places over England, Wales, and Scotland to Moray. It has been found in many parts of Ireland.
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