"Head rough. Ocelli absent. Tongue obsolete. Maxillary palpi obsolete. Tibiæ without spurs. Fore-wings with all main veins and costa connected by bars near base, 1b furcate, forked parting vein strong." (Plate [I]., figs. 22, 23, 24, 28, 29.)
"By no means an extensive family, yet of universal distribution. It stands more conspicuously isolated than any other group of Lepidoptera, for although it is without doubt a terminal development from the Micropterygidæ (that is one from which no existing family has originated), the gap between them is considerable; exotic genera, whilst differing in various details, are remarkably uniform in the more important peculiarities of structure, and do not at all tend to bridge the gap. The relatively large size of the Hepialidæ (of which some species exceed six inches in expanse of wing) may be attributed to the larval habits, which render these insects independent of the seasons or fluctuations of food-supply, thus removing the check which ordinarily limits growth. The modified type of neuration may have resulted directly from the increase of size, involving a great strengthening of the main veins beneath the costa to support the weight. As a consequence of this strengthening, the flight of the larger species is very powerful, and to this, combined with a choice of larval food, which is often rather indiscriminate, may perhaps be ascribed the wide range of the group, rather than to its antiquity. It is probably of Indo-Malayan origin, and must have existed in that region long enough to acquire fixity of type before its dispersal, which, geologically speaking, may not have been exceedingly remote."—(Meyrick.)
There are two genera represented in New Zealand.
1. [Hepialus]. 2. [Porina].
Genus 1.—HEPIALUS, F.
"Antennæ ⅛ to ¼, in male lamellate or simple. Palpi short, drooping, hairy. Posterior tibiæ usually densely rough-haired, in male sometimes with long projecting tuft above. Fore-wings with vein 7 from angle, 8 remote, 9 and 10 stalked. Hind-wings as fore-wings, 8 seldom connate or stalked with 7." (Plate [I]., figs. 22 and 23, neuration of Hepialus virescens, 24 head of ditto.)
"A genus of universal distribution, but not very numerous in species. Ovum spheroidal, smooth. Larva elongate, active. Pupa with segmental whorls of spines, enabling it to move actively before emergence."—(Meyrick.)
Represented by one species only—the largest moth we have in New Zealand.
HEPIALUS VIRESCENS, Dbld.
(Hepialus virescens, Dbld., Dieff. New Zeal., ii. 284; White, Taylor New Zeal., pl. i. 6. Hepialus rubroviridans, White, l.c., pl. i. 1. Charagia virescens, Walk., Bomb., 1569; Scott, Trans. Ent. Soc. N. S. Wales, ii. 28. C. fischeri, Feld., pl. lxxx. 1. C. hectori, Butl., Proc. Zool. Soc. Lond., 1877, 380. Hepialus virescens, Meyr., Trans. N. Z. Inst., xxii., 211.)