Leather-leaf star-miner

The genus was described by Edward Meyrick as follows:

Antennae in ♂ rather strongly ciliated. Palpi rather short, obliquely ascending, second joint with tolerably appressed scales. Thorax with strong double posterior crest. Forewings 7 and 8 separate, 7 to termen. Hindwings without cubital pecten, 3 approximated at base to 4, 4 and 5 short-stalked, 6 and 7 stalked. The larvae of P. polypodii were described by Watts as follows:

Length when full-grown about 12-14 mm. Cylindrical; ground-colour bright green, head and prothoracic shield dark grey-brown; skin transparent, disclosing a bright -green alimentary canal and dorsal vessel. Tubercles small, green; setae light grey. Skin covered with minute pile except in vicinity of tubercles. Thoracic legs normally developed; prolegs on segments 3-6 inclusive and 10; ventral prolegs possess complete circles of 16-18 crochets each, the anal prolegs possess only a semicircle of 10-12 crochets each. Spiracles small, circular. Hudson described the pupa of the species as follows:

The pupa is enclosed in a cylindrical cocoon of thin white silk, constructed within the final blotch-mine, the larva having prepared an exit through which the pupa protrudes its anterior portions prior to emergence. Hudson described the adults of the species as follows:

The expansion of the wings is about 1⁄2 inch. …

This species is endemic to New Zealand. It has been recorded in both the North Island and the South Island, as far south as Banks Peninsula.

The larva will produce black coloured liquid from its mouth if disturbed. The larva will exude a silken thread if shaken from the leaf which they then use to return to their host. When the adult moth is disturbed it runs about in an unpredictable directions adding pauses to its activity. In flight this moth moves erratically and rapidly. The adult moth is on the wing from November to December and is attracted to light.

It is assumed that the eggs of this species are laid on the host plant. The larvae feed over winter and spring on P. eleagnifolia, mining the leaves. Young larvae create a number of mines radiating from the base creating a star shape. These mines are filled with frass. After the leaf withers, the larva moves on to another leaf. As the larva grows, the size of the mine also increases. At the final stage of larval development, the older larvae create a large blotch mine in which it pupates. Larvae have been collected in August and September. These larvae pupated in October and emerged as adult moths from the 20th of October until the 1st of December.