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Free-living caddis (Edpercivalia)

Taxonomic group

Hydrobiosidae: Edpercivalia

Diagnostic features

The New Zealand hydrobiosid caddis larvae have pincers on their forelegs. Edpercivalia larvae are best recognised by the shape and colouring of the prosternal plate (between the forelegs). This plate is slightly wider than long, and has a strong “bump” in the black pigmentation at the midpoint of the hind edge.

Typical habitats

Edpercivalia larvae are most common in South Island stony streams, particularly in mountainous areas.


They are predators, feeding on other stream invertebrates.

Indicator value

  • Hard bottom:9
  • Soft bottom: 6.3

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

Edpercivalia are most likely to be found in cold water streams with good water quality. They have tolerance values of 9 (hard bottom sites) and 6.3 (soft bottom sites).