1. Thorn-like process or outgrowth of the cuticula and part of it (without a joint). Example: the spines on the scutellum in many Stratiomyidae and in Simulium pupae 'tergite IX with 1 small seta and 1 short, slightly curved terminal spine'.
2. Large seta seated in an alveolus. Example: in Heleomyzidae 'the wings often have small but distinctly longer, well-spaced spines mixed with the shorter spines along the leading edge'.