7 Chilopoda – Tracheal system

Centipedes are terrestrial, tracheate arthropods. Spiracles occur on many or most trunk segments, but never on the forcipular segment or the last leg-bearing segment and genital segments. The size of the spiracles increases up to the fourth long tergite covering leg-bearing segments 7-9, to decrease thereafter. In the Pleurostigmophora, the spiracles and atria are covered by numerous cuticular trichomes. The spiracles of the Scolopendrinae are triangular to lengthwise oval, whereas the roundish spiracles of the Otostigminae are often ear-shaped. The tracheal tubules are built by epidermal cells with large nuclei, and very scarce cytoplasm. The tracheae are formed by a flat single-layered epithelium approximately 30 nm in height, which is only extended in the area of the nuclei. Two tracheal stems, originating at the spiracle pair of the third leg-bearing segment, project into the head. Keywords:centipedes; Otostigminae; pleurostigmophora; Scolopendrinae; Spiracles; tracheae; tracheal system