Category Archives: Entomology

Ecdyonurus torrentis (Large Brook Dun/Spinner)

This large and widespread European upwinged fly is inhabitant of the stony rivers. Nymphs are stone clingers.

Ecdyonurus nymph

It is not sensitive to moderate pollution and temperature oscillations.

Large Brook Dun can be found near the bank,  on the bushes, rocks and often on the water surface.

Ecdyonurus torrentis subimago


After final  transformation in the adult insect, smaller groups of males and females swarms above the water.


Interestingly, the same species can be found in brownish and reddish color.

ecdyonurus imagos

Flight period: april – june

Length: about 2 cm

February Red Stonefly (Brachyptera risi & Taeniopteryx nebulosa))

There are two widespread species of february red stoneflies. First is Taeniopteryx nebulosa, which is inhabitant of slow and weedy trout rivers. Second is Brachyptera risi , which prefers stony and fast rivers.


This insect is one of the first in trout season. Hatches occurs from february till april. In some days trout can be ocupied by feeding with this juicy middle-sized stonefly.

Length: 1-2 cm

Body Color: Reddish-Brown

Wings color: Mottled Brown


Yellow Sally (Isoperla grammatica)

In the late spring and early summer this is one of the most important stoneflies. It is widespread and abundant in most of the clear and cold rivers of Europe.


Adult female  of Yellow Sally is often in the trout’s diet,  because it swarms above the riffles and dips abdomen into the water to lay  eggs.

It’s middle-sized stonefly with body length about 1 cm.





Early Brown Stonefly (Protonemura meyeri)

This is abundant and widespread stonefly in high-altitude European rivers.  It’s always in the same habitat as trout and grayling. It prefers cold and clean running water.

Protonemura meyeri

Flight period is from march to may. Although it hatches on the banks and submerged objects, it is often on the water surface, so it is one of the most interesting stoneflies to imitate with artificial dry fly.

Body length is 5 – 9 mm.

Grannom Sedge (Brachycentrus sp.)


Grannom mating pair

This is widespread and abundant spring-time sedge from running waters. It hatches on the open water. Huge swarms can be seen above the high and mid altitude rivers. Waterside bushes and bridges can be buried with grannoms.

Grannom swarm

Length of the wings can vary between 6 to 11 millimeters.  The body is grayish with green or brown tone.  Characteristically, the female has a pouch with green eggs on the abdomen, which will lay walking under water.

Grannom down

Baetis rhodani (Large Dark Olive)

First In Season

Upwinged flies are the most popular
insects in the fly fishing . There’s a reason for that: They are the easiest to see and there are plenty of types in different colors , which attracts  our attention to its beauty . Although the late winter present numerous midges, we act like we don’t see them, but we get very excited when we see the first upwinged fly in the season – Baetis rhodani .

Subimago of this insect sail
helpless on the water and this attracts the fish to feed in the atmosphere . Rising and splashing were able to see earlier, because the midges were on the water in the middle of winter, but… Now the real thing begins : A sailboats , who we follow to the moment when fish turn them into a bite . “Bluurrrpp!” So powerful ! After a long winter break , dry fly anglers are on the move again.
Ventral view – important for tying a fly
Nymphs & Emergers
Nymph-lovers are excited too , because the same insect nymphs become active even weeks before the hatch.  They belong to the “agile darter” group of the Ephemeridae nymphs. In early spring, they are more often on the menu, less protected and more easily killed.

Instinct makes them get out of the shelter and come to the surface to hatch. Many of them are being eaten in that stage.
Baetis imago
Finally, there is the adult stage, which is important too. Baetis lay their eggs under water. The female walks into the water, using submerged objects. Then again, she is vulnerable and available to fish jaws.

Size: About 1 cm + tails

Habitat: Rivers

1st Hatch: February-May

2nd Hatch: October-December