Sunday 6 November 2011

Hydrobiosis parumbripennis

Derek Grzelewski's excellent read The Trout Diaries mentioned using the Rhyacophila fly when fishing. Something about it made me curious... to be honest I don't remember what it was now, but here's some information I managed to dig up from my bookcase, relating to the Hydrobiosis parumbripennis, which is native to New Zealand and belongs to the "large family of caddises, the Rhyacophilidae".

(From 'An introduction to the fresh water insects of New Zealand', by J. G. Pendergrast and D. R. Cowely)

The adults (shown above) are about 16 mm. long. Their fore-wings are mottled with light and dark brown, a distinct dark-brown patch being present close to the anterior margin and about two-thirds of the way to the apex of the fore-wing.

The H. parumbripennis larva has along, bright green body with brown pigmentation dorsally. 

The head is elongated and has an area of dark pigmentation interrupted by unpigmented spots, towards its posterior end.

The thorax has a single dorsal thoracic plate which has a diamond-shaped area of dark pigmentation, again with unpigmented spots.