Oemopteryx contorta ( Needham & Claassen, 1925 )

Verdone, Chris J., Williams, Bronwyn W., Beaty, Steven R., Holland, Victor B., Grubbs, Scott A. & Dewalt, Edward, 2025, The adults, larvae, and systematics of the Nearctic Oemopteryx Klapálek, 1902 (Plecoptera: Taeniopterygidae), Zootaxa 5595 (1), pp. 1-94 : 28-37

Oemopteryx contorta ( Needham & Claassen, 1925)

( Figs 14–19 )

Dark Willowfly

Taeniopteryx contorta Needham & Claassen, 1925: 242 . Holotype male (CUIC), Jaffrey, Cheshire Co., New Hampshire, USA. Brachyptera contorta : Frison 1942: 353.

Oemopteryx contorta : Illies 1966: 63.

Oemopteryx contorta : Zwick 1973: 313.

Brachyptera (Oemopteryx) contorta : Hitchcock 1974: 125.

Oemopteryx contorta : Ricker & Ross 1975: 141.

Oemopteryx contorta : Nelson 1982: 11.

Oemopteryx contorta : Stewart 2000: 59.

Distribution. USA.—CT, MA, MD, ME, NC, NH, PA, TN, VA, WV ( DeWalt et al. 2024) ( Fig. 6 ).

Material examined. Connecticut: Middlesex Co., Lyman’s Brook, East Hampton, [41.57583, -72.50310], 24 March 1937, H.H. Ross, 1M ( INHS: Plecoptera 6237); same data, 3L ( INHS: Plecoptera 6238); same data, 4L ( INHS: Plecoptera 6239); same data, 4L ( INHS: Plecoptera 6240); same data, 2L ( INHS: Plecoptera 6241). Maryland: Frederick Co., Fishing Creek, W of Lewiston, [39.53230, -77.47451], 2 March 1958, P.H. Freytag, A.H. Mason, 1M ( UKIC); Fishing Creek, Mountaindale, [39.51938, -77.45117], 2 March 1958, P.H. Freytag, A.H. Mason, 3L ( UKIC); Fishing Creek, abv. reservoir, Mountaindale, [39.53230, -77.47451], 2 March 1958, P.H. Freytag, 1M ( UKIC); [Little] Tuscarora Creek, west (northwest) of Yellow Springs, [39.48533, -77.46820], 20 February 1958, P.H. Freytag, A.H. Mason, 27L ( UKIC); UT Tuscarora Creek, Hamburg Rd., Frederick Municipal Forest, 39.49710, -77.47465, 9 March 2020, P.N. Hogan, 3F ( WKUC); UT Tuscarora Creek, W of Yellow Springs, [39.47951, -77.47121], 26 January 1958, P.H. Freytag, 5L ( UKIC); same location, 20 February 1958, P.H. Freytag, A.H. Mason, 10M, 4F ( UKIC); same location, 23 February 1958, P.H. Freytag, 4M ( UKIC); same location, 29 March 1958, P.H. Freytag, 4F ( UKIC); same location, 13 April 1958, P.H. Freytag, A.H. Mason, 5F ( UKIC). Garrett Co., Bull Glade Run Snaggy Mountain Rd., Garrett State Forest, 39.49162, -79.45862, 25 February 1996, S.A. Grubbs, 5L ( WKUC); Middle Fork Crabtree Creek, north bank, 150 feet from spring, Savage River State Forest, 39.51461, -79.15975, 20 March 2020, P.N. Hogan, 1F ( WKUC); UT Murley Run, Garrett State Forest, 39.49568, -79.46557, 18 March 2020, P.N. Hogan, 1F ( WKUC). Massachusetts: Franklin Co., Dean Branch, Pratt Corner, Cuchman Rd., Amherst Watershed, 42.41863. -72.47600, 18 February 2023, emerged 22 February 2023, R.E. DeWalt, R. Smith, 1M, 1E ( INHS: Insect Collection 1505820); same data, emerged 28 February 2023, 1F ( INHS Insect Collection 1505841); same data, emerged 14 March 2023, 1F ( INHS Insect Collection 1505841). New Hampshire: Coos Co., UT Cutler River, John Shelburne Ski Trail, White Mountains National Forest, 44.25960, - 71.28637, 16 June 2021, S.A. Grubbs, L. Myers, 3F ( WKUC). Grafton Co., [no waterbody], Plymouth, [43.75694, -71.68860], 26 April 1969, [no collector], 1F ( INHS: Insect Collection 795559). North Carolina: Burke Co., Hall Creek, SR 1969, South Mountain State Park, 35.60501, -81.78294, 17 January 2019, C. Verdone, S. Beaty, V. Holland, B. Kondratieff, 1F ( NCDWR). Caldwell Co., Wilson Creek, Brown Mountain Beech Rd., 35.97978, - 81.76504, 18 January 2019, emerged, 31 January 2019, C. Verdone, S. Beaty, V. Holland, B. Kondratieff, 2F, 1E ( NCDWR). Graham Co., Wolf Laurel Creek, FS 81F, Nantahala National Forest, 35.36318, -83.98268, 2 March 2008, A.L. Sheldon, 1F ( WKUC). Haywood Co., Dark Prong, Pisgah National Forest, 35.32713, -82.83004, 14 April 2006, J.L. Robinson, 1F ( WKUC); Flat Laurel Creek, off Flat Laurel Creek Trail, 35.31837, -82.88342, 20 March 2013, A.L. Sheldon, 1M ( WKUC); same data, 35.32434, -82.89617, 5M, 4F ( WKUC); same data, 35.31754, -82.88237, 12 April 2014, 1F ( WKUC); UT Flat Laurel Creek, Big Sam Trail, 35.32311, -82.89297, 12 April 2014, A.L. Sheldon, 1F ( WKUC); UT Flat Laurel Creek, Little Sam Trail, 35.31664, -82.89178 12 April 2014, A.L. Sheldon, 2F ( WKUC); UT Flat Laurel Creek, off Flat Laurel Creek Trail, 35.32142, -82.89275, 20 March 2013, A.L. Sheldon, 3F ( WKUC). Jackson Co., Big Witch Creek, Dobson Rd., 35.51611, -83.22500, 21 March 2022, R. Tetreault, 1F ( NCDWR); Cullowhee Creek, Picnic Grounds Rd. 35.31387, -83.18734, 23 January 2024, C. Verdone, V. Holland, D. Harwood, 4L ( NCDWR). Macon Co., Bearpen Branch, FS 711H, Nantahala National Forest, 35.18183, -83.62044, 17 March 2013, A.L. Sheldon, 3F ( WKUC); same data; 35.18194, -83.62048 24 February 2014, 2F ( WKUC); Bearpen Creek, FSR 711, [35.18579, -83.61411], 5 April 2014, S. Beaty, V. Holland, E. Fleek, 2F ( NCDWR); Middle Creek, 11 [km] SW Highlands, Rt. 106, [35.01325, -83.31506], 31 January 1963, W.S. Brooks, L.J. Stannard, 1M ( INHS: Plecoptera 6252); White Oak Creek, FS 711, Nantahala National Forest, 35.20191, -83.58354, 29 February 2008, A.L. Sheldon, 1F ( WKUC); Wine Spring Creek, FS 711F, Nantahala National Forest, 35.17949, -83.59764, 23 February 2014, A.L. Sheldon, 1M, 1F ( WKUC); Wine Spring Creek, FS 711H, Nantahala National Forest, 35.17964, -83.61994, 10 April 2014, A.L. Sheldon, 1F ( WKUC); Wine Spring Creek, horse camp nr. FS 711, Nantahala National Forest, 35.17740, -83.61368, 24 February 2014, A.L. Sheldon, 2F ( WKUC). Rutherford Co., Pool Creek, Bottomless Pool Rd., 35.42897, -82.22901, emerged 28 January 2019, C. Verdone, S. Beaty, V. Holland, B. Kondratieff, 1M, 1F, 1L, 2E ( NCDWR). Swain Co., Bear Creek, 140 m above campsite 75, Great Smoky Mountains National Park, [35.48709, -83.59321], 9 March 2003, D. Etnier, 1F ( NCDWR); Bunches Creek, Bunches Creek Rd., 35.53649, -83.20885, 1 March 2022, C. Verdone, S. Beaty, V. Holland, R. Tetreault, 1M ( NCDWR); Deep Creek, Deep Creek Campground, N Bryson City, [35.46122, -83.43612], 26 February 2001, B. Kondratieff, R. Zuellig. R. Kirchner, 1F ( CSUIC). Transylvania Co., Coontree Creek, NC 276, 35.28967, -82.76324, 29 January 2019, C. Verdone, V. Holland, 1M, 1F ( NCDWR); Davidson River, NC 276, 35.28810, -82.76286, C. Verdone, V. Holland, 1M ( NCDWR); UT to Greenland Creek, FS trail 488, 35.15451. -82.00331, C. Verdone, S. Beaty, V. Holland, 1M ( NCDWR); small seep, E. Devils Courthouse Overlook parking lot, 35.30460, -82.89965, 4 April 2006, J.L. Robinson, M. Geraghty, J. Robinson, 1M ( WKUC). Watauga Co., [no waterbody], Blowing Rock, [36.13513, -81.67760], 23 March 1940, T.H. Frison, C.O. Mohr, A.W. Hawkins, 1F, 2E ( INHS: Plecoptera 6242). Yancey Co., Rock Creek, end FS 5521, Pisgah National Forest, 35.77315, -82.21896, 2 March 2017, A.L. Sheldon, 1F ( WKUC); seeps, Buncombe Trail, Pisgah National Forest, 35.74279, -82.27468, 27 April 2019, M.L. Metzger, 1M, 1F ( WKUC); Setrock Creek, Mitchell Trail, 35.75561, -82.24325, 26 February 2014,A.L. Sheldon, 1F ( WKUC); South Fork Upper Creek, Buncombe Trail, Pisgah National Forest, 35.73634, -82.27946, 27 April 2019, M.L. Metzger, 1F ( WKUC); South Toe River, Pisgah National Forest, 35.75176, -82.22039, 2 March 2017, A.L. Sheldon, 4F ( WKUC); Upper Creek, Pisgah National Forest, 35.73162, -82.25181, 4 March 2017, A.L. Sheldon, 2F ( WKUC). New York: Franklin Co., Dutton Brook, Rt. 3, nr. [Middle] Saranac Lake, [44.25175, -74.23864], 15 March 2006, L. Myers, R. Younghanz, 1F ( CSUIC). Orange Co., unnamed tributary to Lake Stahehe, CR 106, E. Lake Stahehe, Palisades Interstate Park, 41.23630, -74.15080, 9 March 2009, emerged 20 March 2009, L. Myers, 3M, 2F, 4L, 2E ( CSUIC). Pennsylvania: Carbon Co., Broad Run, upstream of reservoir, 40.871183, -75.871289, 2 March 2011, T. Daley, 10L ( NCDWR). Lackawanna Co., White Oak Run, 40 ft above falls, 41.497078, -75.514229, 4 march 2011, T. Daley, 10L ( NCDWR). Snyder Co., Penns Creek, 40.79885, -76.85794, 16 April 2014, no collector data, 1M, 5F ( WKUC). Westmoreland Co., Maul Spring, Powdermill Nature Reserve, 40.13921, -79.25883, 17 April 1994, S.A. Grubbs, 1M ( WKUC); Powdermill Run, Powdermill Nature Reserve, 40.15171, -79.27028, 7 April 1993, S.A. Grubbs, 1F ( WKUC); UT Laurel Run, Powdermill Nature Reserve, 40.13406, -79.27769, 15 April 1997, S.A. Grubbs, 1M ( WKUC); UT Powdermill Run, Powdermill Nature Reserve, 40.14108, -79.26786, 29 April 1993, S.A. Grubbs, 1F ( WKUC); same data, 17 March 1994, 1M ( WKUC); same data, 8 April 1994, S.A. Grubbs, 2F, 2L ( WKUC); same data, 3 May 1994, 1F ( WKUC). Wyoming Co., South Brook, 50 m upstream Opossum Brook, 41.41998, -76.21470, 22 March 2011, T. Daley, 5L ( NCDWR). Tennessee: Sevier Co., Starkey Creek, 0.25 mi above Sams Branch, Great Smoky Mountains National Park, [35.58029, -83.66040] February 1987, D. Etnier, 3M ( CSUIC). Unicoi Co., Red Fork, FS 230, 36.13904, -82.29004, 11 April 2014, A.L. Sheldon, 2F ( WKUC). Virginia: Greene Co., [no waterbody], Stanardsville, [38.2974, -78.44010], 21 March 1940, T.H. Frison, C.O. Mohr, A.W. Hawkins, 5F ( INHS: Plecoptera 6249); same data, 1F ( INHS: Plecoptera 6248; same data, 1M ( INHS: Plecoptera 6250). Grayson Co., Cabin Creek, US 58, 36.607284, -81.521194, 16 February 2024, C. Verdone, 1M ( NCDWR); Lewis Fork, Jefferson National Forest, 36.68908, -81.51917, 3 March 2007, A.L. Sheldon, 2F ( WKUC); same data, 36.69414, -81.51462, 1M ( WKUC); same data, 36.67407, -81.52554, 1M, 1F, 1L ( WKUC); Lewis Fork, at VA-603 [near Grindstone Gap], Mt. Rogers National Recreation Area, [36.69408, -81.51479] 18 February 1990, R.F. Kirchner, K.W. Stewart, 1M ( INHS: Insect Collection 795556); Lewis Fork, Rte 603, 36.69455, -81.51460, 16 February 2024, C. Verdone, 1M ( NCDWR). Montgomery Co., [no waterbody], Brush Mountain, 2 mi W of Blacksburg, [unable to approximate coordinates], 5 March 1961, R.L. Hoffman, 1M ( INHS Plecoptera 6251). Smyth Co., Big Laurel Creek, Rte 603, 36.68190, -81.56527, 16 February 2024, C. Verdone, 1M, 1F ( NCDWR). Rappahannock Co., Thornton River, along US-211 at picnic area, Shenandoah National Park, [38.71333, - 78.15972], 28 February 1975, R.W. Baumann, 2M, 2F ( INHS Insect Collection 795561); [no waterbody], Sperryville, [38.65694, -78.22639], 17 March 1940, T.H. Frison, C.O. Mohr, A.W. Hawkins, 2F ( INHS Plecoptera 6244); same data, 1F, ( INHS Plecoptera 6245); same data, 3M ( INHS Plecoptera 6246); same data, 2L ( INHS Plecoptera 6247). Tazewell Co., Cove Creek, Rt. 662, 37.17837, -81.29900, 14 February 2024, C. Verdone, 9M, 14F ( NCDWR). Washington Co., Straight Branch, at US-58, Jefferson National Forest, [36.64579, -81.73445], 18 February1990, K.W. Stewart, R.F. Kirchner, 1M, 4F, 7L ( INHS: Insect Collection 795562). Wythe Co., Cripple Creek, Speedwell, [36.81834, -81.17447], 22 May 1940, T.H. Frison, C.O. Mohr, A.W. Hawkins, 1F ( INHS: Plecoptera 6243); East Fork of Reed Creek, 5 mi N Wytheville at Hwy 717, George Washington and Jefferson National Forest, [37.01016, -81.18438], 17 February 1990, K.W. Stewart, R.F. Kirchner, 5F ( INHS: Insect Collection 795572); East Fork Stony Creek, Rt. 717, 6 mi NW Wytheville, [37.00932, -81.18248], 3 March 1979, R. Kirchner, 10M, 2F, 15L ( CSUIC). East Fork Stony Fork [ US Stony Fork Campground] along VA-717, Jefferson National Forest, [37.00932, -81.18246], 28 March 1978, R.F. Kirchner, G. T. Voreh, 3M, 10F, 3L ( INHS: Insect Collection 795558). West Virginia: Pocahontas Co., Hills Creek, off Hwy 39, Falls of Hills Creek Scenic Area, [38.17764, -80.33669], 16 February1990, K.W. Stewart, R.F. Kirchner, 1F, 1L ( INHS: Insect Collection 795557); North Fork Cherry River, 14 mi W [E] Richwood at WV- 39, [38.19262, -80.35379], 16 February1990, K.W. Stewart, R.F. Kirchner, 26L, INHS Insect Collection 877509). Randolph Co., Trout Run, near Czar, 38.72510, -80.19430, 24 March 1992, S.M. Clark, 1F ( WKUC).

Adult male ( Fig. 15A ). Macropterous. Length of forewings 7.9–8.8 mm (n = 10). Length of body 6.1–9.2 mm (n = 10). General body color dark-brown.

Head ( Fig. 15A ). Dorsum of head mostly dark-brown. Labrum pale anteriorly, brown posteriorly. Anterior frontoclypeus brown. Frons with a dark-brown U-shaped marking. Antenna longer than body. Scape, pedicel, and flagella dark brown. Scape with a distal notch on anterior face. First flagellum subdivided at distal 1/4. Rugosities anterolateral to lateral ocelli and ecdysial suture. Interocellar area uniformly dark-brown and slightly depressed. Occasionally with a pale stripe spanning area between eyes across lateral ocelli and interocellar space. Occiput with brown rugosities. Medial areas of the frons, interocellar surface, and occiput covered with fine, pale, clothing hairs.

Thorax ( Fig. 15A ). Pronotum subquadrate, wider than long (length 0.8X width) with posterior width slightly wider than anterior width; brown overall with brown rugosities. Anterior and posterior margins of pronotal flange often pale. Disk with irregular brown rugosities; a transverse sinuous furrow at anterior 1/4. Prosternum moderately sclerotized. Meso- and metathorax dark-brown, heavily sclerotized dorsally and ventrally. Thoracic nota and coxae uniformly covered with sparse, short, fine clothing hairs. Legs with contrasting pigment. Femur pale, distal portion of femur with darker pigment. Tibia brown, darker brown on proximal and distal portions; apex of tibiae with 2- stout apical spines. Tarsus dark-brown. Legs uniformly covered with dark, short stout setae. Wings hyaline; venation brown. Forewing with light mottling; without costal crossveins between humeral crossvein and apex of the subcostal vein which may be forked. Hindwing mottling less developed, absent in anal region.

Abdomen. First abdominal tergite with a broad pale stripe medially ( Fig. 14B ); terga 2–7 uniformly brown; terga 8–9 with a posteromedial membranous cleft. Sterna 2–8 with a pair of anterior sublateral oval brown spots. Abdominal segments 1–9 lightly covered with short, fine clothing hairs. Sternum-9 with a lightly sclerotized broadly circular vesicle ( Fig. 15C ) that is attached to sternum-9 from directly beneath the vesicle. Sterna 7–8 lightly sclerotized. Sternum-9 elongated into a scooped plate ( Fig. 16D ), width subequal from base to apex; apex square with rounded lateral margins ( Fig. 15C ); plate with numerous long setae on dorsal and ventral surfaces ( Figs 16A, 16D ); plate covering sternum-10 ventrally and extending beyond.

Terminalia ( Figs 16A–E ). Abdominal segment-10 nested within segment-9. Anterior margin unsclerotized. Tergal sclerite-10 with a subtle medial cleft and paired submedial flattened anterior processes with raised scale-like armature ( Figs 16A, 16C ). Cercus 4-segmented, excluding vestigial apical segment ( Figs 16A, 16D ), and with a low, rounded, posteriorly directed basalcercal process covered in socketed setae and sensilla basiconica ( Figs 16A, 16D ). Basal plate of tergum-10 relatively flat, sclerotized with a wrinkled texture ( Figs 16A, 16C ). Lateral struts present, median strut absent; basal plate with a small medial point ( Figs 16A, 16C ). Basal bulb ( Fig. 16A ), glabrous, oval, bulbous, moderately sclerotized and with an oval inner bulb bearing a small hollow stalk, which terminates at a pore on the anterior face near the junction of the 2-processes of the anterior epiproct.Anterior epiproct prong fused to basal bulb, divided halfway to base, each arm terminating a distal facing, lightly-sclerotized foot-shaped process that is pointed at its apex and slightly recurved ventrally ( Figs 16A–B, 16D–E ). Posterior epiproct prong subdivided into 2-processes. Ventral process lightly sclerotized, divided near apex into 2-glabrous, rounded lobes ( Figs 16A, 16E ). Dorsal process pouch-like, armed with posteriorly directed spine-like setae with an apical sleeve containing 2–3 internal filaments that are not eversible; filaments sometimes visible on left side of basal bulb. Paraprocts subdivided into 2-parts, symmetrical anterior paraprocts and asymmetrical bi-lobed posterior paraprocts. Anterior paraproct, conical, medially directed, tapering to a point ( Figs 16A, 16E ); apical 1/4 subequal in width. Posterior paraprocts ( Figs 16A, 16D ) subdivided, fused at base; left outer prong short, flattened and lightly sclerotized; left inner prong long, flattened, twisted and striated, terminating with an acute sclerotized spine; right outer prong flattened and moderately sclerotized. Right inner prong tubular, twisted and striated, tapering to apex.

Adult female ( Figs 14A , 15B ). Macropterous. Length of forewings 9.1–9.6 mm (n = 10). Length of body 7.7– 9.1 mm (n = 10). General body color brown. Overall appearance similar to male. Wings hyaline; venation brown; Forewing with light mottling; without costal crossveins between humeral crossvein and apex of the subcostal vein which may be forked ( Fig. 15D ). AA1 vein of forewing with short fine setae ≤ 0.5mm ( Fig. 15F ). Hindwing mottling less developed, absent in anal region ( Fig. 15D ). First abdominal tergite with a broad pale stripe medially ( Fig. 14C ); terga 2–8 uniformly brown dorsomedially; terga 9–10 sclerotized dorsally and laterally. Lateral margins of abdomen segments 1–8 unsclerotized. Sternum-8 weakly sclerotized. Subgenital plate weakly sclerotized ( Fig. 15E ) with a U-shaped notch and a lightly sclerotized medial tab, which may be enfolded ( Figs 17A–B ). Sternum-9 parabolic, produced just beyond the apex of abdominal segment-10 ( Figs 15E , 17A ); length of free portion of sternum 0.8X basal width; uniformly covered with long setae that become longer posteriorly; lateral margins slightly narrowing to a broadly rounded apex. Cercus 5–6 segmented, excluding vestigial apical segment ( Figs 15E , 17A ).

Ovum. Unknown.

Mature larva ( Fig. 18A ). Length of male body 7.0– 8.4 mm (n = 10), female body 7.5–8.7 mm (n = 10). General color light-brown. Integument glossy, much of the body with sparse, fine, hair-like sensillae and socketed stout setae, observable at>100X magnification. Specimens generally preserve in a curled posture with the head touching or approaching the abdomen apex, similar to other Taeniopterygidae .

Head ( Fig. 18A ). Dorsum of head light-brown with dark brown maculations variously developed. Antelabrum light-brown; anterior margin with a dense brush of golden setae. Postlabrum light-brown; anterior frontoclypeus pale to light-brown. Frons with a brown U-shaped marking with posterolateral extensions; light-brown subrectangular markings directly anterior to lateral ocelli. Interocellar area diffusely light-brown, pale at junction of ecdysial suture. Occipital area diffusely light-brown and with irregular brown rugosities. Eyes with pigmented ommatidia reduced, not reaching eye margins. Antennal scape, pedicel and flagella brown; dorsobasal apically inserted setae absent ( Fig. 18C ); antenna slightly shorter than body ( Fig. 18A ).

Maxilla ( Figs 19A–B ). Lacinia triangular with a straight inner margin. Lacinia with 2-apical, cupped teeth and 2–5 subapical denticles on ventral face. Apical teeth subequal in length; relative length of apical teeth to palm length difficult to discern due to wear. Inner palm margin19 stout socketed marginal setae below apical teeth; first marginal seta robust. Basal 1/3 of palm with a cluster of>10 thin dorsal setae. A single acutely pointed sensilla basiconica on palm surface near the basal 1/5. Galea with a dense brush of curved setae on the distal apical margin, which transition to sparse peg-like setae at the apical 1/4; a thin patch of setae on inner margin below apical setae, which extends about halfway to base. Length of galea, including apical setae, 1.1X length of lacinia; width of galea 1.1X the lacinia width. Maxillary palp with 5-segments; 2X length of lacinia; palp with sensilla basiconica sparsely scattered over entire surface.

Mandible. Right mandible ( Fig. 19C ) bicuspid, outer cusp with 3-teeth, inner cusp with 1-tooth. Molar pad adorned with marginal rows of pointed acanthae (length 2.1X width). Palm dorsum with 9–11 dorsal sensillae adjacent to molar pad (requires focusing through the mandible) ( Fig. 19C circle inset); the proximal basal corner with a marginal patch of 3-hair-like, branched setae. Ventro-apical setal patch extending from outer cusp to beyond the inner cusp basally (indicated by dotted line in Fig. 19C ). Left mandible ( Fig. 19D ) bicuspid, outer cusp with 5- teeth, inner cusp with 1-broad concave tooth. Molar pad with marginal rows of rounded acanthae and long pointed acanthae (length 4.0X width). Palm dorsum with 1–12 dorsal sensillae adjacent to molar pad (requires focusing through the mandible) ( Fig. 19D circle inset); the proximal basal corner with a marginal patch of 5-hair-like, branched setae. Ventro-apical setal patch extending from outer cusp to beyond the inner cusp basally (indicated by dotted line in Fig. 19D , square inset).

Thorax ( Fig. 18A ). Pronotum wider posteriorly; light-brown with faint rugosities and a pale posteromedial spot. Length of forewing pad 3.3X width. Length of hindwing pad 1.8X width. Venter of thorax pale. Prothoracic presternum mostly glabrous with light-brown spicules laterally and a pair of elongate lateral cervical sclerites. Prothoracic basisternum and furcasternum light-brown; spicules dense medially and sporadic distally. Mesothorax with an oval prefurcasternal pit; light-brown spicules present both anterior and posterior to pit; lateral areas glabrous. Mesothoracic basisternum with light-brown spicules mostly concentrated medially. Furcasternal pit present between mesothoracic legs; furcasternum triangular, as long as wide (length 1.0X width). Metathoracic basisterna with a medial patch of light-brown spicules and a pair of furcasternal pits. Anterior face of femur usually pale, darker distally; dorsum pale ( Fig. 18D ). Femur and tibia with a dorsal fringe of silky setae (not shown); length of femoral setae less than 1/2 the width of the femur; length of tibial setae about equal to tibial width. Anterior and posterior faces of the femur with scattered short stout setae. Tibial callus darkened ( Fig. 18D ). Tarsus with a sparse dorsal fringe of silky setae (not shown); tarsus light-brown and becoming progressively darker distally. Venter of tibia and tarsus with scattered short stout setae.

Abdomen. Dorsum of abdomen usually uniformly light-brown; sometimes darker anteriorly and lighter posteriorly on posterior segments ( Fig. 18E ). Posterior margins of terga with a single row of short, stout sensillae. Posterior margins of tergum-8 and tergum-9 with a pair of thin, erect, submedial setae. Venter of abdomen pale; sterna 1–8 with light-brown spicules. Sternum-9 with an elongate plate (male = length 1.5X width; female = length 1.5X width); plate width relative to sternal width (male = 0.9X; female = 0.8X). Male plate ( Fig. 18F ) with sides slightly widening towards posterior margin of sternum-9, posterolateral margins convex, evenly rounded towards apex. Female plate ( Fig. 18G ) narrower basally, widest at posterior margin of sternum-9; posterolateral margins convex, evenly narrowing towards apex. Plates of both males and females with stout setae sparse on basal half, becoming denser towards apex. Cercus uniformly brown; dorsobasal apically inserted setae absent ( Fig. 18B ); cercus about as long as body ( Fig. 18A ).

Diagnosis. Oemopteryx contorta is defined in the adult male by the anterior processes on tergum-10 and by the presence of a distinctive broad pale strip on tergum-1, which the female also possesses. The larvae are usually separable from O. bimaculata sp. nov. by the concolorous abdominal terga. Oemopteryx contorta also differs from O. tuscarora sp. nov. by its darkened tibial callus, a character it shares with O. bimaculata sp. nov.

Biological notes. Oemopteryx contorta is endemic to the Appalachian Mountains with records known from at least five EPA Level III ecoregions (Blue Ridge, Ridge and Valley, Central and North Central Appalachians and the Northeast Highlands), in at least ten states ranging from Tennessee north to Maine. Verdone et al. (2017) reported O. contorta from Georgia, but this record now pertains to O. bimaculata sp. nov. as described above. Oemopteryx contorta is expected to occur in the Blue Ridge EPA Level III ecoregion in Georgia, but no specimens are currently known. Additionally, records of O. contorta from Alabama reported by Grubbs (2006) are considered dubious given their location in the Southwestern Appalachians Level III ecoregion. These specimens could not be located to confirm their identity. Elevations of collection locations range between 135 m to 1720 m ASL. Larvae have been collected from streams with drainage areas ranging from 0.8 km 2 to 104.7 km 2. Nelson (1982) first described the larva of O. contorta and reported a univoltine life cycle for this taxon.

Based on known records, O. contorta appears to be allopatric with O. bimaculata and O. tuscarora sp. nov. Both O. contorta and O. bimaculata sp. nov. occur in the Central Appalachians; however, O. contorta appears to be distributed north and east of the Dissected Appalachian Plateau Level IV ecoregion, which may be a basis for which to delineate the ranges of the two species. Available records indicate adults are typically active from mid-January to late April; however, females have been collected as late as mid-June at higher elevations and northern latitudes. The North Carolina Biological Assessment Branch has just one larval record of O. contorta and consequently, a pollution tolerance value is currently unknown for this taxon. NatureServe (2024) has assigned this species a conservation rank of G4, defined as a low risk of extinction due to its extensive range and numerous populations, but with possible cause for some concern as a result of threats to habitat, or other factors.

Figures

FIGURE 6. Distribution map of the Oemopteryx contorta Group species. Records include examined material, BOLD records included in genetic analysis and unpublished data from the CNCI.

FIGURE 14. Oemopteryx contorta, Cove Creek, Tazewell Co., Virginia, adults. A. Live female. B. Male tergum one, dorsal. C. Female tergum one, dorsal. [morphological abbreviations: see Table 1].

FIGURE 15. Oemopteryx contorta, Cove Creek, Tazewell Co., Virginia, adults. A. Male habitus, dorsal. B. Female habitus, dorsal. C. Male sterna, ventral. D. Female wings. E. Female sterna, ventral. F. Female forewing, lateral. [morphological abbreviations: see Table 1].

FIGURE 16. Oemopteryx contorta, Pool Creek, Rutherford Co., North Carolina, adult male.A. Terminalia, dorsal.B. Terminalia, close, dorsal. C. Abdominal terga, dorsal. D. Terminalia, lateral. E. Epiproct, lateral. [morphological abbreviations: see Table 1].

FIGURE 17. Oemopteryx contorta, Hall Creek, Burke Co., North Carolina, adult female. A. Abdominal sterna, ventral. B. Subgenital plate. [morphological abbreviations: see Table 1].

FIGURE 18. Oemopteryx contorta, South Brook, Wyoming Co., Pennsylvania, larva. A. Habitus, dorsal. B. Right cercus, lateral. C. Right antenna, lateral. D. Legs, anterior. E. Abdomen, dorsal. F. Male sterna, ventral. G. Female sterna, ventral. [morphological abbreviations: see Table 1].

FIGURE 19. Oemopteryx contorta, UT Lake Stahehe, Franklin Co., New York, larval mouthparts, ventral. A. Right lacinia, galea and maxillary palp. B. Left lacinia, galea and maxillary palp. C. Right mandible; dorsal sensillae (circle inset). D. Left mandible; ventro-apical setal patch (square inset); dorsal sensillae (circle inset). [morphological abbreviations: see Table 1].