Kluge 2004: Fig.13

Figure 13. Tergalii.

AB Abdomen of male Siphlonurus/fg4 lacustris [Siphlonurus] (boundaries of pigmented spots shown by dotted lines): A larva; B imago (arrow shows trace of tergalia attachment). C Scheme of musculature of larval abdominal segment (tergalial muscle shown by longitudinal striation, tracheal trunks by transverse striation). DG position of ribs and tracheae in tergalii of various mayflies (ribs shown by integral lines and dotted, tracheae shown by dotted lines): D procerus [Ameletus]; E montanus [Ameletus]; F immanis [Siphlonurus]; G eugeniae [Rhithrogena]. (AB, DF from Kluge 1989a; C from Kluge 2000).

Abbreviations: a.r  anal rib; c.r  costal rib; gsty  gonostyli buds of larva and gonostyli of imago; ter  tergalius; Tm  tergalial muscle; to  tracheostium.