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Stony cased caddis (Philorheithrus)

Taxonomic group

Philorheithridae: Philorheithrus

Diagnostic features

Philorheithrus caddis larvae construct robust cases made of coarse sand grains. Each of the three thoracic segments have hard (“sclerotised”) plates. The fore legs and mid legs are raptorial (designed for grasping prey).

Typical habitats

Philorheithrus larvae are most common in fast flowing, cold water streams, particularly in mountainous areas.


They are predators of other stream invertebrates.

Indicator value

  • Hard bottom: 8
  • Soft bottom: 5.3

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

The presence of Philorheithrus larvae is an indication of good habitat and water quality, particularly where a range of mayflies or stoneflies is also present. They have tolerance values of 8 (hard bottom sites) and 5.3 (soft bottom sites).