Kluge 2004: Fig.8

Figure 8. Reduction of wings and pterothorax among mayflies.

AB Siphlonurus/fg3 spp., mayflies with most usual plesiomorphic proportions: A general view; B median section of pterothorax. CD Turbanoculata, mayflies with reduced hind wings: C vernus Curtis 1834 [Baetis], mayfly with vestigial hind wings; D median section of pterothorax of Cloeon/fg* diptera [Ephemera], mayfly without hind wings. EF individual variability of wing size in an undescribed short-winged species of Rhithrogena/fg2 from Chukotka (River Amguema 12 km below meteorological station, 1 IX 1976, leg. E. Makarchenko). (A from Tshernova 1964, B from Kluge 2000, C from Kluge 1997d).

Abbreviations: MTm2  median tergal muscle of mesothorax; MTm3  median tergal muscle of metathorax; PhM  middle phragma; SA.Sm  subalar-sternal muscle; S.ESm2  scuto-episternal muscle of mesothorax; S.ESm3  scuto-episternal muscle of metathorax; S.LPNm  scuto-lateropostnotal muscle.