Alloperla usa Ricker, 1952

Stark, Bill P. & Kondratieff, Boris C., 2010, Larvae Of Eight Eastern Nearctic Alloperla Species (Plecoptera: Chloroperlidae), Illiesia 6 (20), pp. 267-276 : 274

Alloperla usa Ricker

( Figs. 21-25 )

Alloperla usa Ricker, 1952:178 .

Holotype ♂ (Illinois Natural History Survey), Tennessee, Sevier Co., Little Pigeon River near Alum Cave Creek, Great Smoky Mountains National Park

Material examined. North Carolina: Burke Co., Jacob’s Fork, Old NC Hwy 18, South of Pleasantford , 35.59° N, 81.57° W, 3 May 2005, B.C. Kondratieff, R.F. Kirchner, R.E. Zuellig , D. R. Lenat , 1 pharate male larva ( CSU) .

Mature larva. Body length 9.0 mm. General color brown without distinctive pattern. Head slightly darker over ocelli and pale forward of median ocellus ( Fig. 21 ). Anterolateral margin of head somewhat angulate and slanted from near antennal base to labrum. Anterior pronotal margin with ca. 5-6 moderately thick setae on corners and 2 long thin setae on posterior corners ( Fig. 21 ). Mesonotal and metanotal wingpads without obvious outer or inner marginal setae but short, thick basal setae abundant on both segments, extending slightly beyond mesonotal wingpad on surface of metanotal wingpad ( Fig. 22 ). Ventral tibial fringes and dorsal femoral fringes apparently absent on all legs; dorsal tibial fringes sparse ( Fig. 24 ). Abdominal terga without pale spots; posterior fringe reduced to a few short thick setae near lateral margins and several (ca. 6) long thin setae; intercalary setae restricted to areas near lateral margins ( Fig. 23 ). Cerci with 18 apparent segments ( Fig. 25 ), vertical fringe sparse and restricted to segments 11-16, primarily on ventral side; a few scattered dorsal fringe setae occur on segments 13-15.

Comments. Larvae of A. usa may have been incorrectly identified as a possible southeastern species of Utaperla in the past due to the slightly elongated head and the poorly developed cercal fringe. Mature larvae however are more robust than those of Utaperla and the two can be readily separated by the pronotal setation which consists of numerous long setae on both the anterior and posterior margin in species of that genus ( Stewart & Stark 2002).

Figures

Figs. 21-25. Alloperla usa larval structures. 21. Head and pronotum. 22. Mesonotum and metanotum. 23. Abdominal terga 8-9. 24. Right foreleg. 25. Lateral aspect of cercus, dorsum left.