Stonefly Species Sweltsa exquisita (Sallflies)

Source: A Contribution To The Knowledge Of Sweltsa Exquisita (Frison) And Sweltsa Occidens (Frison) And Description Of A New Species Of Sweltsa From The Northern Rocky Mountains, U. Sweltsa A. (Plecoptera: Chloroperlidae)

Male. General color yellow in life, head with black ocellar rings, pronotum yellow except for wide black lateral margins, abdomen with wide black stripe covering terga 1 to 8, black mark on tergum 8 much broader than long as shown in Frison (1935) and sometimes even slightly divided medially. Tergum 9 with a definite, bare elevated transverse process on the anterior margin (Figs. 2 & 3). The anterior margin of the process varies from entire to slightly emarginate (Figs. 2 & 3). In dorsal aspect, the epiproct is erectile, elongate, and subparallel (Fig. 4); in lateral view, slightly enlarged subapically (Figs. 6 & 7), in dorsal aspect, apex sharp and bare (Fig. 5), laterally, rounded and bare at edge (Figs. 6 & 7); in dorsal aspect, epiproct surface covered with dense pile of appressed long setae, extending to base (Figs. 4 - 7), in lateral aspect, 2/3 or more of epiproct, covered by pile-like hairs, ventrally bare (Fig. 6). Aedeagus tubular basally, dorsal aspect subtriangular, with two small dorsal lobes, bearing long thin setae (Fig. 8), lateral, terminal aspect exhibiting paired curled hornlike lobes (Fig. 9); surface with pores (Fig. 9).

Female. Color and dark markings similar to male. Subgenital plate large, nearly covering sternum 9, sides subparallel, with a broadly rounded apex, that can sometimes appear truncate (Fig. 26).