flat-backed millipede

6131  Hello! My name is Nikki.  I found this guy at work in the gorge today, at the base of the Niagara Falls. Ontario, Canada

This is a flat-backed millipede (family Polydesmida) in the family Xystodesmidae; it looks like Sigmoria trimaculata – see https://tinyurl.com/yct6dqg9 for an image. These are harmless detrivores, but have an interesting defensive mechanism. When disturbed (as in being handled roughly) some species give off a chemical compound that includes cyanide (not enough to be harmful to a human. If you sniff one carefully, you might detect a faint odor of almonds. Ed Saugstad, retired entomologist; Sinks Grove, WV.