Maccaffertium ithaca (Light Cahill) Mayfly Nymph Pictures

Maccaffertium is a Latinized version of the name of the world-renowned mayfly systematist, W. Patrick McCafferty. And, mediopunctatum is constructed from roots of medi- meaning middle, and punct- meaning point, so I assume this species has some distinctive feature midpoint in its anatomy. Assuming my logic is valid, perhaps someone else can tell you what the feature is.

The distribution of this species is confined to the states and provinces lying east of the N. American continental divide.

This is the same specimen that I collected from a stream nearby.
Can anyone tell me the history( name basis) for this insect ?
Is it common across the country?

Thanks....