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Watch your step. The first summer I canoed the Upper Delaware
River, I wondered about white gauzy material, a lot of it the size of silver
dollars, fastened above the water surface onto bridge piers and huge boulders.
Much later I learned that each gob of material was a dried
secretion that protects up to 1000 small eggs. As they hatch, small larvae
drop into the water and make homes on the bottom, where they become hellgrammites,
insects with powerful jaws, prized by fishermen for bait.
Hellgrammites spend three years on the bottom, often in riffles
and strong currents, where they cling to rocks and devour small prey. After
three years of breathing by gills, they move onto land to pupate in small
burrows and emerge as large, harmless flying insects called dobsonflies.
The picture below was snapped during a hike on the Tusten
Mountain Trail just above Ten Mile River. I was surprised that a hellgrammite
was so active on land until I recalled that the species supplements its gill
system with spiracles, small openings that allow it to survive temporarily
on land by drawing oxygen from the atmosphere.
—Ed Wesely
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