24. Zapada chila (Ricker, 1952)

Smokies Forestfly

http://lsid.speciesfile.org/urn:lsid: Plecoptera.speciesfile.org:TaxonName:6008

(Figs. 157–160)

Nemoura (Zapada) chila Ricker 1952:55. Holotype male (Illinois Natural History Survey), Walker (Camp) Prong, Great Smoky Mountains National Park, (Sevier Co.), Tennessee, USA

Zapada chila: Illies, 1966:249

Zapada chila: Grubbs et al., 2015:1313

Zapada chila: Stark, 2017:214

Distribution. USA: TN (DeWalt et al. 2022)

Male. Macropterous. Body length 4.6–4.9 mm, forewing length 6.2–7.1 mm (n = 4). Four unbranched cervical gills are present. The length:maximum width (L:MW) ratio for the outer lateral gills is ca. 9.8 compared to ca. 9.4 for the inner medial gills (Fig. 159; Grubbs et al. 2015). Cerci simple and unmodified (Fig. 157). Paraprocts with two sclerotized lobes; inner lobes short and thin, outer lobe broadly quadrate. Epiproct recurved over 10 th tergite (Figs. 157–158); broadest basally and open dorsally, with a distinct membranous structure that is medially expanded and distally spatulate (Fig. 157); laterally sinuous in shape, showing the hump-shaped membranous structure mesally (Fig. 158); dorsal sclerite larger than the ventral sclerite in lateral view, the two structures run ca. parallel from base nearly to mid-point (Fig. 158).

Female. Macropterous. Body length 5.3 mm, forewing length 7.2–7.7 mm (n = 2). Cervical gills same as male. The 7 th sternum is produced as a broadly-rounded subgenital plate that extends slightly over the anterior margin of the 8 th sternum (Fig. 160); posterior margin of 8 th sternum slightly concave medially.

Larva. Undescribed. Adult gill characteristics of Zapada, however, are identical to those in the larval stage. This should permit positive identification of larva of this species (Stark 2017).

Comments. Zapada chila is considered a rare species. Only 13 adult specimens have been collected across a 65-year time span from a single stream (Walker Camp Prong) at the eastern Tennessee edge of Great Smoky Mountains National Park (Grubbs et al. 2015).