What Kind of Bug Is This? Common Bug Groups

Is It a Centipede? How to Tell Centipedes From Look-Alikes

Centipedes: 4 marks to check, what they are often confused with, whether they bite or sting, and where they turn up, quoted from university entomology and IPM sources.

These pages help you narrow a bug down to its group from what you can see. They are not medical advice. Seek medical care promptly for severe symptoms or any sign of an allergic reaction.

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At a glance

Group: Class Chilopoda
Body plan: Elongated, flattened animals bearing one pair of legs per body segment; despite the name, most species have closer to 30 pairs of legs total rather than a hundred; the house centipede commonly found indoors has 15 pairs of legs, and in adult females the last pair is nearly twice the body length and extends backward.
Size: Adults are usually brownish and more than 1 inch long; the house centipede commonly found indoors measures about 3-4 inches including legs and antennae, with a body length of 1-1.5 inches.
Bites or stings: When provoked, some large centipedes can inflict a painful bite.
Where you find them: Usually found in damp, dark places such as under stones, leaf mulch, or logs; house centipedes are commonly found inside buildings (basements, floor drains, under concrete slabs, etc.).

How to tell it is one of the centipedes

Legs per segment differ: centipedes have one pair of legs per segment, while millipedes have two (more common) or four pairs per segment.
Body cross-section differs: centipedes are flattened, while millipedes are cylindrical to slightly flattened.
Official comparison table (Table 1): millipedes have 2 or 4 legs per segment / last pair not extended backward / move slowly / rarely bite; centipedes have 1 leg pair per segment / last pair extended backward / move quickly / can bite.
When provoked, some large centipedes can inflict a painful bite, while millipedes do not bite when disturbed (though some species exude a defensive liquid).

Often confused with

People most often mix centipedes up with:

Millipedes

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.

Bites and stings

When provoked, some large centipedes can inflict a painful bite. Seek medical care promptly for severe symptoms or any allergic reaction.

Pest or beneficial?

Centipedes are generally beneficial in the garden; house centipedes are considered beneficial because they feed on silverfish, cockroaches, and other household pests, though large numbers can indicate an underlying pest problem in the home.

Where they turn up

Usually found in damp, dark places such as under stones, leaf mulch, or logs; house centipedes are commonly found inside buildings (basements, floor drains, under concrete slabs, etc.).

How to photograph it for identification

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.

FAQ

Do centipedes bite or sting?

When provoked, some large centipedes can inflict a painful bite. Seek medical care promptly for severe symptoms or any sign of an allergic reaction.

What is the quickest way to recognize centipedes?

Legs per segment differ: centipedes have one pair of legs per segment, while millipedes have two (more common) or four pairs per segment.

Are centipedes a pest?

How do I tell centipedes from millipedes?

Legs per segment differ: centipedes have one pair of legs per segment, while millipedes have two (more common) or four pairs per segment. Body cross-section differs: centipedes are flattened, while millipedes are cylindrical to slightly flattened. Official comparison table (Table 1): millipedes have 2 or 4 legs per segment / last pair not extended backward / move slowly / rarely bite; centipedes have 1 leg pair per segment / last pair extended backward / move quickly / can bite. When provoked, some large centipedes can inflict a painful bite, while millipedes do not bite when disturbed (though some species exude a defensive liquid). The Millipedes page lists its own marks.

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