Northern Crayfish (Virile Crayfish)
The northern crayfish (or virile crayfish) is reddish brown or green without prominent markings. The pincers are green or blue-green with orange tips and in adults are conspicuously studded with whitish or yellowish knobs. Paired dark blotches run lengthwise along the abdomen. The rostrum has conspicuous notches or spines near its tip.
The virile crayfish is the largest of crayfish in the Prairie Region and in the state. The papershell (or calico) crayfish differs from this species in having pincers that are gray, purple, or pink, a pale lengthwise stripe along the middle of the carapace and abdomen, and a rostrum without lateral notches or spines. The spothanded crayfish usually has a dark spot at the base of the moveable finger and a saddle mark at the back edge of the carapace.