Bug Identifier
Identification

Bugs With Lots of Legs: Centipedes and More

By the Bug Identifier Editorial Team. Updated September 27, 2026. 3 minute read.

Bugs with far more than six legs are not insects at all. This guide covers 3 of them.

How to narrow it down

Narrow it down with three quick checks. Count the legs: insects have six, spiders and ticks have eight, and centipedes and millipedes have many more. Check for wings, even folded ones. Then compare size against a coin: a US penny is 19 mm across. Our bug identifier tool does this filtering for you.

The 3 bugs

House Centipede

House CentipedeScutigera coleoptrata25–35 mmNuisance

A fast, yellowish-gray centipede with 15 pairs of very long legs that races across floors and walls at night. It hunts silverfish, cockroaches and spiders.

Tell-tale sign: Fifteen pairs of long, banded legs. Risk: House centipedes rarely bite; a bite feels like a mild bee sting.

Millipede

MillipedeOxidus gracilis20–40 mmNuisance

A slow-moving, cylindrical arthropod with two pairs of legs on most body segments. Millipedes eat decaying leaves and often migrate indoors after heavy rain.

Tell-tale sign: Rounded, segmented body with many short legs. Risk: Millipedes don't bite; some release a fluid that can stain or irritate skin.

Pill Bug

Pill BugArmadillidium vulgare8–14 mmHarmless

A small land crustacean that rolls into a tight ball when disturbed, also called a roly-poly. It eats decaying plant matter in damp soil and mulch.

Tell-tale sign: Gray, armored, segmented body with seven pairs of legs. Risk: Pill bugs are harmless and only occasionally nibble seedlings.

Which ones should you worry about?

0 of the 3 bugs in this guide can bite or sting. None of them are considered medically significant. The rest are harmless or simply a nuisance.

Comparison at a glance

House CentipedeMillipedePill Bug
GroupCentipedes, Millipedes & CrawlersCentipedes, Millipedes & CrawlersCentipedes, Millipedes & Crawlers
Scientific nameScutigera coleoptrataOxidus gracilisArmadillidium vulgare
Size25–35 mm20–40 mm8–14 mm
ColorsGray, Tan and YellowBrown and BlackGray and Black
Legsmany legs (30 or more)many legs (30 or more)14 legs
WingsNoNoNo
Bites or stingsBitesNoNo
RiskNuisanceNuisanceHarmless
Key featureFifteen pairs of long, banded legsRounded, segmented body with many short legsGray, armored, segmented body with seven pairs of legs

Frequently asked questions

What is the most common one?

Among the bugs in this guide, the house centipede and millipede are the ones people ask about most.

Which of these are dangerous?

None of them are medically significant, though some can bite or sting.

How can I identify a bug I found?

Use the free bug identifier tool: choose the number of legs, wings, main color, size and where you found it, and it will list the closest matches.