The giant stoneflies are identifiable by two main features. The head of these larvae appears to be tilted downward, because it a vertical orientation. Pteronarcyidae have gills on both thoracic and abdominal segments. It is one of only two families of stoneflies to have thoracicgills. These large stonesflies are shredders, eating mostly algae and decomposing leaf litter. Giant stoneflies are fairly sensitive to pollution and can be used to indicate good water quality.
Wings developing in wing pads. Mouthparts suitable for chewing. Gills digitiform and located near mouthparts, on neck, sides of thorax, or underside of base of abdomen, never on top or sides of abdomen. Two tarsal claws per leg. Only two tails (cerci).
The body is dark and can be quite large (up to 2 inches), with profusely branching gills under the thorax and basal abdominal segments; the wing pads are divergent.
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