We rarely see centipedes but found one in the house last night, scuttling around on the slate floor downstairs. We trapped it, photographed it in its plastic jail cell, and released it into the garden where it belongs.
Arthropods (insects, spiders, crabs and their kin) are invertebrates with segmented bodies, jointed limbs and a chitinous exoskeleton. Centipedes are arthropods but not insects: they belong in the subphylum Myriapoda which includes:
• Chilopoda – centipedes
• Diplopoda – millipedes
• Pauropoda – sister group to millipedes
• Symphyla – resemble centipedes
The Australian Museum has a reasonably good overview of the Myriapoda here.
Wikipedia notes that, “Centipedes are known to be highly venomous, and often inject paralyzing venom,” and (less seriously), “Despite the name, centipedes can have a varying number of legs, ranging from 30 to 354. Centipedes always have an odd number of pairs of legs. Therefore, no centipede has exactly 100 legs.” (For something even less serious, try The Centipede’s Dilemma.)
Our visitor belongs in Scolopendromorpha, variously known as ‘tropical’ or ‘giant’ centipedes (because they are both). Ours was no giant but was a respectworthy 80 mm or so.