Ichneutica averilla

Ichneutica averilla was first described by George Hudson in 1921 under the name Melanchra averill.[3] Hudson used the two female specimens of the moth collected by Averil Lysaght in December 1920 on Mount Taranaki.[3] The lectotype specimen of this species is held at the Museum of New Zealand Te Papa Tongarewa.[2] In 1924 Alfred Philpott, thinking this was a new species, described this moth under the name Melanchra furtiva from specimens collected around Mount Arthur as well as in the mountainous areas near Lake Wakatipu.[4] In 1988 John S. Dugdale placed this species within the genus Graphania and recognised Melanchra furtiva as a new synonym.[5] In 2019 Robert Hoare undertook a major review of New Zealand Noctuidae.[2] During this review the genus Ichneutica was greatly expanded and the genus Graphania was subsumed into that genus as a synonym.[2] As a result of this review, this species is now known as Ichneutica averilla.[2]

Ichneutica averilla observation confirmed by Robert Hoare

Hudson described the larvae of this species as follows:

The length of the full grown larva is about 1+1⁄8 inches (30 mm). Cylindrical, slightly flattened, tapering moderately towards head; hindslope moderate, rather irregular; segmental divisions deep, especially towards ventral surface. Head ochreous-brown, with dark stripe on each side. Body rather dark purplish-grey on back, pale green below lateral line, with a very irregular paler intermediate area of dull orange-ochreous; a very broken pale subdorsal line, its components slightly convergent on each segment; eight very conspicuous black bars on the lateral portions of segments 5-13 [A1–A8], with a distinct paler patch behind each bar; these bars terminate on the spiracle and are charachteristic; legs and prolegs green, tipped with brown. Rather variable in depth of colour and distinctness of markings ...[6]

Hudson, in his original description, described the female adult of the species as follows:

The expansion of the wings of the female is about 1+5⁄8 inches. The fore wings have the costa nearly straight and the termen rather obliquely rounded with slight sinuations ; pinkish-brown much suffused with grey, especially towards the base and termen ; the principal markings are very finely indicated in black ; there is a conspicuous curved longitudinal streak from the base to about 1⁄8 ; the first line is indistinct, very wavy, faintly outlined in brown; the claviform is small, cone-shaped; the orbicular is large, irregularly oval, almost wholly outlined in black ; the reniform is large, rather indistinct, outlined in brown towards the base, but otherwise faintly indicated by grey shading; the second line is very faint, grey, sharply bent inwards before the dorsum ; there is a series of dark-edged whitish subterminal dots and a V-shaped dark spot near the tornus; the tornal area is clouded with brownish-ochreous and the cilia are also brownish-ochreous. The hind wings are greyish-ochreous, darker towards the termen ; the cilia are greyish-ochreous with whitish tips. The head, thorax, and fore legs are greyish-white, very finely speckled with pinkish-brown ; the basal third of the antennae is whitish, the remaining portion blackish.[3]

I. averilla is a medium-sized moth.[3] The adult male of the species has a wingspan of between 33 and 41 mm whereas the female has a wingspan of between 36 and 41 mm.[2] The forewings of this species are pinkish brown coloured, tinged with grey and have dark markings with a notable streak running lengthwise from the forewing base.[3] There is also a distinctive v-shaped dark mark on the posterior corner of the wing.[3] The hind wings of this species are greyish brown in colour.[3]

This species can be confused with I. mutans but can be distinguished on forewing colour as I. averilla has a ground colour of uniform red-ochreous shade where as I. mutans is more brown with blackish hints.[2] Also the antemedian forewing line is normally distinct in I. mutans where as in I. averilla it is absent or just a hint of pale scaling is present.[2]

This species is endemic to New Zealand.[7] It is found in the North Island, but only in the Mount Taranaki area.[3][2] This species is widespread throughout the South Island,[2] where it has been collected in such areas as on Mount Arthur, around Ben Lomond, Elfin Bay, Lake Luna and Lake MacKenzie in Otago,[4] and at the Cass Basin in the Waimakariri River catchment.[8] I. averilla is also present on Stewart Island.[2]

I. averilla inhabits mountainous country.[5] However it can be found down to sea level altitudes in the southern parts of the South Island, such as in the Catlins.[2]

The adult moths can be found on the wing from November to March.[2]

After emerging the larvae eat their egg shell.[6] The larvae of I. averilla have been found to feed on plants in the genus Plantago and it is likely the larvae of this species feeds on a variety of plant hosts.[8][2]