Is It a Millipede? How to Tell Millipedes From Look-Alikes

• Legs per segment differ: millipedes have two (more common) or four pairs of legs per segment, while centipedes have only one pair per segment.
• Body cross-section differs: millipedes are cylindrical to slightly flattened, while centipedes are flattened.
• Millipedes do not bite when disturbed (though some species exude a defensive liquid), while centipedes may bite when provoked.
• The official comparison table (Table 1) shows millipedes move slowly with the last leg pair not extended backward, while centipedes move quickly with the last leg pair extended backward.
• Millipedes have a hard outer skin and curl into a spiral upon death, a feature centipedes do not share.

People most often mix millipedes up with:

• Centipedes

Open the other page and compare its list against the marks above; the differences are usually in the antennae, wings or the way the body is divided.

Do not bite when disturbed, but some species exude a defensive liquid. Seek medical care promptly for severe symptoms or any allergic reaction.

Millipedes are generally beneficial, helping to break down dead plant matter; but in large numbers they can damage germinating seeds, seedlings, or crops such as strawberries.

Prefer cool, damp places such as under stones, leaf mold, mulch, compost heaps, and piles of grass clippings; they occasionally migrate in large numbers into window wells, basements, and garages, but do not survive indoors for more than a few days.

Get as close as your camera will focus, from directly above, in daylight or a bright lamp. Include the whole body with the legs and antennae in frame; a second shot from the side shows wings and body segments. Put a coin or ruler next to it for scale. For a bite or a bug found on skin or bedding, photograph the bug itself, not the mark. The app names the likely group; use the list above to confirm.