Field plate · Scutigera coleoptrata
House centipede
Thirty long legs, a blur across the basement wall, and entirely on your side: it hunts the insects you actually have a problem with.
Plate 16 of 28. Drawn in profile to the identification marks named below; the scale rule is a drawing convention — sizes are given in the text.
Identification marks
Body 25–35 mm, yellowish with three dark lengthwise stripes, ringed by fifteen pairs of very long, banded legs — the last pair longest. It moves startlingly fast and freezes when lit.
Look-alikes it is confused with
Nothing else in a Pennsylvania house looks like it. Small spiders and silverfish share its rooms, not its outline.
Where it hides in a house
Damp basements, bath and laundry rooms, crawlspaces, and around floor drains — wherever it can hunt silverfish, roaches, carpet beetle larvae, and spiders at night.
Health & property risk, stated plainly
Negligible. It can bite if handled and almost never is; it does not infest food, damage the house, or breed into numbers. A house full of centipedes is a sign of damp and of prey — treat it as a meter reading, not an infestation.
What actually works
Reduce the conditions: dehumidify the basement, fix drips, seal the baseboard gaps it shelters in, and vacuum corners. Fewer prey and fewer damp refuges means fewer centipedes, without a drop of insecticide.
What doesn't
A pesticide program aimed at the centipede itself — you would be paying to remove a predator while leaving the prey and the damp untouched.
When to call a licensed pro
Rarely for the centipede. Call a pro for what it is feeding on, if inspection finds roaches or a heavy silverfish population in stored paper.