Pyrrhosoma is a genus of damselfly in the family Coenagrionidae.
Pyrrhosoma species are rather large damselflies with a mainly red abdomen. They have no postocular spots, black legs and pterostigma are dark. Females are usually also red, but sometimes black marked with yellow. The markings on the thorax, often red, are diagnostic. The antehumeral stripes are in the shape of exclamation marks. They cross the humeral suture whereas normally, these stripes are entirely anterior to that suture (hence the name antehumeral).
Separation from other genera
Red specimens can only be confused with Ceriagrion species, but differ in leg and pterostigma colour, and the distinctive antehumeral stripes. Black females can be confused with females of Erythromma and the black form of Ceriagrion, but they differ by details of the markings on their thorax.
Males are aggressive, but do not keep obvious territories. Males and females oviposit in tandem.