Tagmosis is the evolutionary process of fuse and modifying segments in metameric organisms such as arthropods to form tagmata. In insects, the body segments (somites or metameres) have become fused into three main tagmata: the head, thorax and abdomen. Segments making up each tagma can be either completely fused (e.g. the head capsule) or more loosely connected (e.g. the abdomen).

Evolutionary biology