"Black Willow Fly"
Acroneuria nigrita
common stonefly nymph
Medium-size, dark
species found in limited
numbers on swift northern streams and northern
Rocky Mountains. Mostly black with yellowish-
orange throat and posterior. 7/8ths". June hatch
in east; 4-6 weeks later in west. Also known as
"water crickets."
Other common stoneflies: Brown Willow Fly