About Izatha convulsella (Walker, 1864)
Izatha convulsella (Walker, 1864) has a wingspan of 14–20 mm for males and 13.5–19 mm for females. G. V. Hudson described its larva as follows: the larva lives under the bark scales of rimu trees (Dacrydium cupressinum), and reaches about half an inch in length when full grown. It is stout, with a hard dark brown head and two hard plates on its second body segment. The rest of its body is dull yellowish-brown, with six rows of hard warts, each of which bears a long bristle. Hudson also described the adult of this species: the wing expansion is about half an inch. The forewings are fairly narrow, with an oblique termen; they are dull bluish-grey, irregularly speckled with black and marked with white. There is a dark basal patch, a fairly broad, curved white band starting from the costa at about one-quarter wing length, a very indefinite darker central band, and an indistinct whitish line running from two-thirds of the way along the costa to the tornus. There are three or four small black marks in the disc before the middle of the wing, a black spot beyond the middle, and a much fainter spot before the apex. A series of marginal dots runs from the costa at about three-quarters wing length to the tornus. The hindwings are greyish-ochreous, and darker towards the apex and termen. This species is very similar in appearance to its close relative Izatha gekkonella. The most reliable way to confirm a specimen's identity is to dissect the male genitalia, as I. convulsella males have a comb-like structure in their reproductive organ. Generally, I. convulsella is slightly larger than I. gekkonella, and has fewer grey scales with yellow tips. This gives I. convulsella a more white and grey overall appearance, while I. gekkonella, with a larger number of these yellow-tipped scales, has a more brownish appearance. I. convulsella also has paler hindwings than I. gekkonella. This species is endemic to New Zealand. It is widespread in the eastern part of the South Island. In the North Island, it has only been recorded from Wellington, Ōtaki, Palmerston North, Taihape and Waipawa, and has not been found in Auckland.
