Salomone: Salmonflies are on the move.

We have been waiting a year for their arrival. They are making their move toward the riverbank. Clustering under large, flat rocks and jumbled together in a writhing mass of legs and bodies, the hoard gathers before the exodus to the surface. Salmonflies — a name that turns the head of any true fly fisher — are on the move.

The Latin term for the giant insects, Pteronarcys Californica, sounds like the name of a dinosaur. I guess they are the dinosaurs of the stonefly family. Reaching out over the 3-inch mark, salmonflies appear in the late spring and early summer days on the Colorado River. The biggest trout in the river feast when the salmonflies appear.

There are a lot of factors and misbeliefs surrounding the emergence of salmonflies. I’ve read anglers think the nymphs not only migrate toward shore but crawl upstream. The same has been said for adults. The flight of the winged adult salmonfly goes upriver to compensate for strong currents which move the bugs downstream.

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I’m not so sure about some of the claims I’ve read or heard about salmonflies, but from decades of reveling in the epic emergences, I have observed bugs flying upriver. But that is the result of prevailing winds that blow up the river corridor, pushing the large-winged insects in the wind.

The insects develop as nymphs for up to four years. The nymphs become increasingly active and mobile during the pre-hatch period. The bugs get knocked free from purchase and tumble in the heavy river current that is simultaneously increasing: high, rough water is a common occurrence during the salmonfly hatch.

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The nymphs grow to enlarged proportions. One of the other factors I’ve heard and read is that the magic river water temperature for pushing the nymphs to transition is 56 degrees Fahrenheit. The cumulation of insects will move en masse to the bank and up onto the rocks. A salmonfly must exit the river to hatch unlike mayflies and caddis, which hatch in the river.

The large nymphs crawl great distances before their skin grows tight and splits on the back, at which point the insect forces itself out of its dried exoskeleton. When the hatch is really happening, insect husks gather like dried leaves on the bank. Remnants from the day before cling to pine tree bark and smooth boulders.

After emerging, the newly-winged adults wait in the sun to gain function in their wings. Wrinkled, mashed wings stretch and fill, taking shape. The freshly winged adults lumber clumsily through the air. The hummingbird-sized insects fluttering on the winds inadvertently end up on the water. Any adult salmonfly struggling on the surface near the bank will attract the attention of a trout.

With the adults in the air, anglers have the chance to experience epic dry-fly fishing. Despite the high water, if a trout can find a feeding lane or area out of the heavy current, the fish will feed until insects protrude from their gullet.

The adults pair up and mate in riverside vegetation. Females develop a black, egg cluster after mating. The females returning to the river to deposit their eggs creates the best dry fly fishing. These are not the young trout from last year feeding either. The big bugs bring out the big fish.

Cutbank monsters venture out to hammer the clumsy fliers. Deep water denizens rise from their underwater caves to partake of the gluttony. Massive feeding occurs both above and below the surface.

Nymphing with a black Pat’s Rubber Legs will bring fish to the net. Any large dry fly presented in the cushion of easier water along the riverbank will gather the appropriate attention. Fly fishers who witness an epic salmonfly hatch experience stellar nymph and dry fly fishing.

Step up with your tippet — rough water, fish size and the intensity of the feeding activity demand heavy line. The weight of deep-water nymph rigs and the repeated flogging with a dry fly make fishing strenuous. Five weight rods are the generic option but fly fishers regularly reach for six weights to compensate for the increased size of everything.

Anglers eager with anticipation are poised, ready to exploit the hatch. Salmonflies provide an epic opportunity where rewards loom as large as the bugs. Black dinosaurs with orange pinstripes create dry fly nirvana when the salmonflies arrive.