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Double gill mayfly (Tepakia)

Taxonomic group

Leptophlebiidae: Tepakia

Diagnostic features

Tepakia mayfly nymphs have a flattened body form, with “M” shaped patterning on the abdominal segments. The double gills are leaf-like, but with a filament that does not originate from the apex of the gill.

Typical habitats

Tepakia larvae are most common in bush covered streams in the north of the North Island.


Leptophlebiid mayflies feed by scraping diatom algae and other organic matter from stone surfaces.

Indicator value

  • Hard bottom: 8
  • Soft bottom: 7.6

The tolerance values (ranging from 0 to 10) give an indication of which are the sensitive taxa (values of 8 or more) and which are the tolerant taxa (values of 3 or less). For more information see: Indicator species

High abundances of Tepakia are indicative of good habitat and water quality, particularly if other mayflies or stoneflies are common or abundant. They have tolerance values of 8 (hard bottom sites) and 7.6 (soft bottom sites).