Northern Crayfish (Virile Crayfish)
The northern crayfish (sometimes called the virile crayfish) is reddish-brown or green without prominent markings. The pincers are green with orange tips and in adults are conspicuously studded with whitish 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 calico (“papershell”) crayfish (O. immunis) differs from this species in having pincers that are gray or purple, a pale lengthwise stripe along the middle of the carapace and abdomen, and a rostrum without lateral notches or spines.