### Identification The Black Stonefly (*Acruroperla atra*) is a striking exception to the usually drab world of stoneflies. Measuring between 20–30mm, this insect is draped in a velvety, midnight-black exoskeleton that looks almost like polished obsidian. The most reliable field mark is the vivid shock of burnt-orange or reddish-orange on the upper segments (femora) of its legs, creating a high-contrast "knee-high" look against its dark body. Unlike many other stoneflies, their wings are soot-colored and held flat over the back, and their two "tails" (cerci) are notably short and stout, giving them a compact, armored appearance.
### Habitat & Range This is a creature of the cold and the ancient. You’ll find *A. atra* in the cool-temperate rainforests and sub-alpine regions of South-Eastern Australia, particularly the Victorian Alps, New South Wales, and Tasmania. They are specialists of high-altitude, oxygen-rich environments, clinging to moss-covered logs and granite boulders alongside frigid, fast-flowing mountain streams.
### Behaviour Observing an *A. atra* is a lesson in slow-motion survival. They are often called "winter stoneflies" because adults emerge during the coldest months. You might spot one lumbering across a patch of snow or a frost-rimed rock with a deliberate, heavy gait. They are poor fliers, preferring to crawl through the leaf litter. When threatened, they don't dart away; instead, they rely on their cryptic coloration against dark, wet stones or tuck their legs in to play dead.
### Diet As nymphs, they are the "shredders" of the stream bed, playing a vital role in the ecosystem by consuming submerged decaying wood and leaf litter. As adults, their mouthparts are functional, but they eat sparingly, occasionally scraping biofilm, algae, or lichen from damp bark to sustain their brief terrestrial life.
### Fascinating Fact While most insects vanish at the first frost, *Acruroperla atra* has "antifreeze" in its blood! They possess specialized proteins that prevent ice crystals from forming in their tissues, allowing them to remain perfectly active and search for mates on top of actual snowdrifts.