Cinygmula (Dark Red Quills) Mayfly NymphView 8 PicturesThis nymph was one of many I collected with vivid white or semi-transparent markings on the front of the head, the sides of the pronotum (Pronotum: The top of the insect prothorax.), and the last abdominal segments.
The femur of this Isonychia bicolor mayfly spinner is highlighted in red.
Femur: The main segment of an insect's leg close to the body, in between the tibia and the trochanter.) are characters that differentiate Epeorus deceptivus from Epeorus longimanus.