Genus 9.—VENUSIA, Curt.
"Face smooth. Antennæ in ♂ bi-pectinated, apex simple. Palpi loosely scaled. Fore-wings with areole simple. Hind-wings with vein 8 anastomosing with cell to beyond middle."—(Meyrick.) (Plate [II]., fig. 13, head of V. verriculata; figs. 25 and 26, neuration of V. undosata.)
We have three species represented in New Zealand.
VENUSIA VERRICULATA, Feld.
(Cidaria verriculata, Feld. cxxxi. 20. Panopæa verriculata, Meyr., Trans. N. Z. Inst. xvi. 62. Pancyma verriculata, ib. xviii. 184.)
(Plate [VI]., fig. 30 ♂, 31 ♀.)
This remarkable species has occurred at Wellington in the North Island, and in the South Island at Christchurch, Ashburton, Dunedin and West Plains.
The expansion of the wings is about 1½ inches. All the wings are pale yellowish-brown, with many straight oblique parallel dull brown lines; on the fore-wings there are three lines broader and more isolated than the rest, running from the apex to the dorsum; on the hind-wings the lines near the middle are rather thicker than the others, and have a broad space on each side of them; all the lines are clearly marked on the abdomen, so that each line appears to be continuous from one side of the moth to the other.
The perfect insect appears from October till May, and frequents the Cabbage Tree Palm (Cordyline), on which its larva probably feeds. According to Mr. Fereday the moth always rests on the dead leaves of the plant, keeping its wings in such a position that the lines are continuous with the parallel veins of the dead leaf, which they precisely resemble in appearance. We have, I think, in this species a most instructive instance of special adaptation to surrounding conditions; and the action of natural selection, in preserving favourable variations of colour and habit, appears to be here unmistakably indicated. Had our investigations been confined to the examination of cabinet specimens only, we might have long remained in the dark as to the explanation of such an unusual type of wing-marking.
VENUSIA XANTHASPIS, Meyr.