The mesothorax and metathorax are rather intimately fused together.
The number of spiracles is greatly reduced; in the adult a pair is present on the mesothorax, sometimes also a pair on the metathorax, and there is always a pair on the first and another pair on the eighth abdominal segment.
Readily movable on the mesothorax, an arrangement usual among insects with the power of rapid running.
The males are very small, free-flying insects with the prothorax, mesothorax and elytra greatly reduced, the latter appearing as little, twisted strips, while the metathorax is relatively large, with its wings broad and capable of longitudinal folding.
Readily movable on the segment (mesothorax) immediately behind - smaller and of less importance where the prothorax is fixed to the mesothorax, as in bees and flies.
3, e, f, g, h), the scutellum of the mesothorax being often especially conspicuous.
Mesothorax: III, Lateral view.
Two pairs of wings are present in the vast majority of insects, borne respectively on the mesothorax and metathorax.
3, t - on the mesothorax at the base of the fore-wings.
In the thorax the pronotum and prosternum are closely associated with the mesothorax, but the pleura of the prothorax are usually shifted far forwards, so that the forelegs are inserted just behind the head.
The Embiidae are feeble, somewhat soft-skinned insects with the prothorax small and the mesothorax and metathorax elongate.
A remarkable feature is the frequent concrescence of mesothorax and metathorax and in some cases, even, their fusion with the anterior abdominal segments.
The prothorax is short and the mesothorax very long, the three pairs of legs closely similar, the wings often highly modified or absent, and the cerci short and unjointed.