Bug FAQStenoperla prasina
Stenoperla prasina · Order: Plecoptera · Family: Eustheniidae
Adults are usually bright green but can also be yellow, with glossy pea-green fore-wings and more translucent hind-wings tinted green. They live near clean, cold, fast-flowing streams with stony bottoms in native bush across New Zealand’s main islands and some smaller islands. Adults fly from October to March, are active at dusk, are attracted to light, and their larvae feed on plant detritus and other aquatic insects.
Source: Wikipedia
How to recognize it
Adults are typically bright green, though some may appear yellow. Fore-wings are glossy pea-green with darker veins; hind-wings are clearer with a green tint on the costal half.
Source: Wikipedia
Size
Wings expand to about two inches across. Body hairs are less than a quarter of the body length.
Source: Wikipedia
Does it bite or sting?
Adults can carry nematode and trematode parasites. Their presence in streams indicates good water quality.
Source: Wikipedia
What it eats
Adults feed on sooty mould fungi, pollen, fern spores, and other plant material.
Source: Wikipedia
When you see it
Adults are on the wing from October through March. They are active at dusk and are attracted to lights.
Source: Wikipedia
Where it comes from
Endemic to New Zealand, occurring on the North, South, Stewart, and Little Barrier Islands.
Source: Wikipedia
Lookalikes
While most adults are green, some may be yellow, which can cause identification issues, especially in early stages.
Source: Wikipedia
More photos
Questions people ask
When can I see adult Stenoperla prasina?
Adults are active from October to March and are most noticeable at dusk.
Source: Wikipedia
What do the larvae eat?
Larvae feed on plant detritus and other aquatic insects in cold streams.
Source: Wikipedia
Are these insects a sign of clean water?
Yes, their presence indicates good water quality in streams.
Source: Wikipedia
Same family (Eustheniidae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Stenoperla_prasina
Look it up elsewhere: GBIF · iNaturalist · BugGuide · Wikipedia
Text written 2026-10-23 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-23.