Stonefly Species Sierraperla cora (Roachflies)

Source: Sierraperla Jewett, 1954 (Plecoptera: Peltoperlidae), Distribution, Egg Morphology And Description Of A New Species

Adult habitus. General color yellow-brown patterned with dark brown (Figs. 13, 33). Head mostly yellow brown, usually with an irregular narrow bar extending across median frons forward of ocelli and often with a narrow brown band extending between ocelli; occiput yellow-brown, sometimes with obscure dusky pigment; some specimens have more extensive dark pigment forward of ocelli. Pronotum with numerous irregular pale spots, some bearing small dark inclusions, particularly in median half of pronotum. Femora yellow-brown to brown, but sometimes slightly darker along dorsal margin; tibiae usually yellow-brown. Wing membrane brown with darker veins except along C and Sc (Fig. 33).

Male. Forewing length 16 - 17 mm. Abdominal tergum 10 with extensive pale pigment surrounding epiproct sclerite; transverse anterior band brown but slightly paler at mid-length (Fig. 14). Epiproct sclerite variable but often with a well defined triangular notch on anterior margin. Abdominal sternum 9 with a wide oval hammer. Ventral aspect of aedeagus a wide membranous bag without sclerites and bearing sparse thin setal spines on and adjacent to lateral and mesal lobes; lateral lobes near mid-length not bifurcate; smaller mesal lobes triangular in outline and often project toward lateral lobes (Fig. 15); apex bearing two pairs of closely appressed lobes, separated by a shallow notch.

Female. Forewing length 18 - 19 mm. Subgenital plate extends over ca. half of sternum 9; lateral margins broadly curved forming a parabolic plate with median apical notch (Fig. 16).

Egg. Hemispherical in lateral aspect, polar aspects circular (Fig. 9). Diameter (n = 12) ca. 364 - 403 µm . Collar a flattened disc covered with shallow pits and reticulations and surrounded by a narrow groove (Fig. 9). Anchor flattened, membranous, ca. 212 - 235 µm in diameter (n = 5), and bearing clusters of globular bodies around outer margin. Lateral surface of egg covered with pits; micropyles located in an irregular ring nearer collar than anterior pole; orifices smaller in diameter than adjacent pits and surrounded by slightly raised, oval rims (Fig. 10). Anterior surface completely covered with pits, surrounded by raised, follicle cell impression walls; walls smooth and of similar height and thickness on all sides; inner dimensions of pits relatively large giving FCIs an open appearance (Figs. 1 - 8, 11 - 12).

Larva. Undescribed. The larval descriptions attributed to this species (Stark & Stewart 1981, Stewart & Stark 1988; 2002) are assigned below to Sierraperla tolowa sp. n. Identification of the larva of Sierraperla cora is discussed in the diagnosis section of Sierraperla tolowa sp. n.