Sweltsa mediana (Banks)

Stark, Bill P., Kondratieff, Boris C., Kirchner, Ralph F. & Stewart, Kenneth W., 2011, Larvae Of Eight Eastern North American Sweltsa (Plecoptera: Chloroperlidae), Illiesia 7 (4), pp. 51-64 : 56

Sweltsa mediana (Banks)

( Figs. 11-15 )

Alloperla mediana Banks, 1911:336 .

Holotype ♀ (Museum of Comparative Zoology), North Carolina, Black Mountain, North Fork of Swannanoa River

Material examined. NORTH CAROLINA: Haywood Co.: Great Smoky Mountains National Park, Cataloochee River , 4 May 1985, K.W. Stewart, B.C. Kondratieff, R . F. Kirchner , 7♂, 4♀, 7 larvae ( KWS) . TENNESSEE: Sevier Co.: Great Smoky Mountains National Park , 2 mi below Newfound Gap Summit, 18 May 1993, B. Stark, B.C. Kondratieff, R . F. Kirchner, 1 pharate larva. Great Smoky Mountains National Park, Greenbriar Cove , 3 mi above Ranger Station, 17 May 1983, B. Stark, B.C. Kondratieff, R . F. Kirchner , 3♂, 3♀, 1 larva ( BPS) .

Mature larva. Body length 7.0-8.0 mm. General color pale brown without distinctive pigment pattern except underlying adult pattern in pharate individuals. Pronotum bearing ca. 14 anterolateral setae and ca. 16 posterolateral setae near margin; posterolateral setal row extends to median suture ( Fig. 11 ).Mesonotum bearing prominent setae scattered along outer margin from base to apex ( Fig. 12 ), and a few inner marginal setae near notch. Metanotum with several outer marginal setae and a large grouping of intercalary setae on wingpad surface; apex of wingpads with interspersed long and short setae. Fore femora with a few fringe setae, tibiae sparsely fringed on outer surface ( Fig. 13 ). Thick setae present on dorsal and ventral margins and a few scattered on femoral surface; tibiae bearing long thin setae and a row of short thick setae along outer margin. Posterior abdominal fringe on tergum 8 with a mixture of thin and thick setae between innermost long setae ( Fig. 14 ); intercalary setae clustered in lateral group of ca. 7. Cerci with ca.15 segments; long dorsal setae in segmental whorls about as long as 1.5 segments ( Fig. 15 ).

Comments. This southern Appalachian species is found in the upper Tennessee River drainage southward in the mountainous regions of North Carolina, South Carolina, Tennessee and Virginia ( Surdick 2004) and earlier records from Alabama were recently assigned to S. hoffmani by Grubbs (2010). Generally S. mediana occurs in larger streams than S. lateralis , but they are known to be sympatric at numerous sites. Mature larvae of S. mediana are the only southern Appalachian Sweltsa species with a long tibial fine setal fringe ( Fig. 14 ). See additional comments above for S. hoffmani .

Figures

Figs. 11-15. Sweltsa mediana larval structures. 11. Head and pronotum. 12. Mesonotum and metanotum. 13. Right foreleg. 14. Abdominal terga 8-10. 15. Lateral aspect of cercus, dorsum left.