An adult specimen of Agabus seriatus, possessing two complete sets of tarsal claws on the left mesotarsus, was collected from a small stream in northeastern Wisconsin.
Snitgen, J. L.
"Tarsal Anomaly Found in an Adult Agabus Seriatus (Coleoptera: Dytiscidae),"
The Great Lakes Entomologist, vol 35
Available at: https://scholar.valpo.edu/tgle/vol35/iss1/11