Sweltsa urticae (Ricker)

(Figs. 36-40)

Alloperla (Sweltsa) urticae Ricker, 1952:185 .

Holotype ♂ (Illinois Natural History Survey), North Carolina, Great Smoky Mountains National Park, Wild Cherry Branch

Material examined. VIRGINIA: Smyth Co.: headwaters of Big Branch, Whitetop, Rt 600, 28 May 1983, B.C. Kondratieff, 4♂, 1♀, 3 pharate larvae (CSU) .

Mature larva. Body length 7.0- 7.5 mm. General color pale brown without distinctive pattern except for pale median ocellar spot due to underlying features of pharate adult. Pronotum bearing ca. 14 anterolateral setae near margin and ca. 18 posterolateral setae (Fig. 36); posterolateral setal row extends to median suture. Mesonotum bearing ca. 12 long outer marginal setae and shorter marginal setae basally and near wingpad apex (Fig. 37); mesonotal surface with few intercalaries. Metanotum with numerous intercalary setae and a mixture of long and short outer marginal setae; several inner marginal setae occur on both meso and metanota. Fore femora with sparse fringe setae and a few long and short thick setae near dorsal margin (Fig. 38); ventral margin with few thick setae. Fore tibiae with sparse outer fringe made up of hairs much shorter than the three long, thick outer setae; inner margin with ca. five short thick setae. Abdominal tergum 8 with posterior fringe widely spaced mesally; lateral intercalary cluster includes ca. 18 setae (Fig. 39). Cerci with ca. 15 segments; long dorsal setae much more prominent than longest ventral setae through segment 10; longest setae only slightly longer than segment (Fig. 40).

Comments. Sweltsa urticae is a southern Appalachian species recorded from higher elevation rheocrenes and streams of southwestern North Carolina into the Great Smoky Mountains and north to the Mount Rogers area in southwestern Virginia (Surdick 2004). It is sympatric with S. lateralis and S. mediana but is more closely related to S. holstonensis and S. voshelli in epiproct structure than to other members of the genus (Surdick 2004). Unfortunately, no larval material for either of these latter species is available. Mature larvae of S. urticae can usually be recognized by the combination of short tibial fine fringe setae (Fig. 34), metanotal wingpads with at least 10 intercalary setae (Fig. 32), and tergum 10 bearing about 10- 12 intercalary setae in lateral clusters (Fig. 33). Larvae of the species are more similar to those of S. pocahontas than to other known eastern species, but the two appear distinct on the basis of number of intercalary setae on tergum 10 and in geographical distribution.