Stonefly Species Diura knowltoni (Nearctic Springflies)

Source: Diura Washingtoniana (Hanson) Resurrected From Synonymy With Diura Nanseni (Kempny) (Plecoptera: Perlodidae), Supplemented With A Description Of The Larva And Egg And Comparison To Other Congeners

Adult habitus. General color dark brown to black in life (Stark et al. 1998). Markings on head and pronotum similar to Diura washingtoniana and Diura bicaudata, except that the sub-triangular yellow interocellular spot is broadly continuous with the longitudinal, yellow median band of the vertex and occiput (Figs. 61, 70). Mesoeusterna and metaeusterna yellow with lateral areas dark brown (Fig. 62). Mesothoracic sternum with an incomplete sternacostal suture separating the basisternum from the furcasternum (Fig. 62).

Male. Body length longer than Diura nanseni, similar to Diura washingtoniana and Diura bicaudata. Macropterous, forewing length similar to Diura washingtoniana and Diura nanseni. Tergum 8 (Fig. 63) exhibits a broad chalice-shaped light-colored area; setose, lacking short, stout sensilla basiconica. Tergum 9 (Fig. 63) similar to that of Diura washingtoniana in that it is nearly divided by a longitudinal, lightly sclerotized median band that extends from the posterior margin to near the anterior margin; setose and on each side of the mesal band exhibits a semicircular area of short, stout sensilla basiconica; immediately laterad of each sensilla basiconica patch there is a broad light-colored band. Tergum 10 pattern of sclerotization similar to Diura bicaudata – the median pale, longitudinal, lightly sclerotized strip is interrupted mesally by a darkly sclerotized band connecting the adjacent darkly sclerotized tergal halves; setose with a single, mesal patch of a few short, stout sensilla basiconica. Epiproct also absent. Each paraproct caudal projection in dorsal and ventral views with its outer surface exhibiting a bluntly pointed protuberance (Figs. 63, 65, 66, 71); setal lengths generally less than those of Diura washingtoniana and Diura nanseni; in lateral view (Figs. 64, 65, 72) the caudal projection of each side is somewhat sub-triangular and tapers to a bluntly pointed apical margin.

Female. Body length longer than Diura nanseni, similar to Diura washingtoniana and Diura bicaudata. Macropterous, forewing length similar to preceding species. Sternum 9 bearing two oblique brown bands (Fig. 67). Subgenital plate similar to preceding species by exhibiting variable shapes (Figs. 68. 73), ca. 3.8 – 4.6 x wider than long. Vagina and spermatheca membranous; spermatheca (Fig. 45 s), similar to that of Diura bicaudata, ovoid or egg-shaped, nearly as long as wide (1.3 x longer than wide); spermathecal duct (sd) 0.5 x length of vagina (v); spermatheca and duct bearing accessory glands (ag).

Larva. Originally described by Frison (1942), other information provided by Stewart and Stark (1984, 2002, 2008) and Stark et al. (1998). Similar to preceding species except that abdominal tergites have broad areas of light color giving the impression that the larva is yellow to light brown with dark brown markings, spinulae pattern of pronotal margins (Fig. 79) similar to Diura washingtoniana and Diura nanseni.

Egg. Initially described by Knight et al. (1965). Collar forms a Y-shaped, triradiate ridge (Stark & Szczytko 1984). Anchor uniquely comprised of three rounded mushroom-shaped plates each located between the arms of the ridged collar (Figs. 80, 81). Chorionic surface similar to preceding three species (Figs. 80, 81).Source: Diura Washingtoniana (Hanson) Resurrected From Synonymy With Diura Nanseni (Kempny) (Plecoptera: Perlodidae), Supplemented With A Description Of The Larva And Egg And Comparison To Other Congeners

http: // lsid. speciesfile. org / urn: lsid: Plecoptera. speciesfile. org: TaxonName: 932 Figs. 61 – 73, 79 – 81