Oemopteryx glacialis ( Barnston, 1848 )

Oemopteryx glacialis ( Barnston, 1848) View in CoL

( Figs 34–38 View FIGURE 34 View FIGURE 35 View FIGURE 36 View FIGURE 37 View FIGURE 38 )

Canadian Willowfly

Nemoura (Brachyptera) glacialis Barnston, 1848: 389 . Holotype male (USNM), Wells , Sacandaga River , Hamilton Co., New

York, USA. Taeniopteryx glacialis View in CoL : Hagen 1861: 36. Perla chicoutimiensis Provancher, 1878: 75 . Syn. Ricker 1952:158. Brachyptera glacialis View in CoL : Frison 1929: 373. Nemoura (Brachyptera) glacialis : Ricker,1938: 131. Taeniopteryx alex Hanson, 1938: 79 View in CoL . Holotype male; (USNM); Sacandaga River, Hamilton Co., New York, USA. Syn. Frison

1942: 251. Taeniopteryx alex : Claassen 1940: 39. Taeniopteryx glacialis : Claassen 1940: 43. Nemoura (Brachyptera) glacialis : Frison 1942: 251. Taeniopteryx (Brachyptera) glacialis : Harden 1942: 321. Brachyptera (Oemopteryx) glacialis : Ricker 1952: 158. Oemopteryx glacialis : Illies 1966: 63. Nemoura (Brachyptera) glacialis : Kimmins 1970: 343. Oemopteryx glacialis : Zwick 1973: 313. Oemopteryx glacialis : Kondratieff & Kirchner 1987: 27. Oemopteryx glacialis : Kondratieff & Kirchner 1988: 205. Oemopteryx glacialis : Grubbs & Bright 2003: 78. Oemopteryx glacialis : Myers, Kondratieff, Mihuc & Ruiter 2011: 96. Oemopteryx glacialis : Grubbs, Pessino & DeWalt 2012: 165.

Distribution. Canada —NB, NS, ON, QC. USA.—CT, MA, MI, MN, NH, NY, VT, WI, WV ( DeWalt et al. 2024 in part) ( Fig. 33 View FIGURE 33 )

Material examined. Canada — Nova Scotia : Colchester County, Salmon River , [Valley Rd.], 45.38938, - 63.18037], 25 March 2016, J. Ogden, 1M ( CSUIC) GoogleMaps . Quebec: Les Pays-d’en-Haut Regional County Municipality , Riverie Du Nord , 1.0 km SE Saine-Adele, at Rue Vallee Du Golf , 45.94328, -74.12445, 21 March 2016, R. E. DeWalt, P.P. Harper, 3M, 1F ( INHS: Insect Collection 659063) GoogleMaps . Le Haut-Saint-Laurent Regional County Municipality, Trout River , Chemin 1 st Concession , 45.00828, -74.31238, 22 March 2016, R. E. DeWalt, P.P. Harper, 3M, 1F ( INHS: Insect Collection 659117) GoogleMaps . USA.— Minnesota: Pine Co., Snake River , 8.6 km NW Grantsburg, 200m upstream St. Croix River, 45.82306, -92.77001, 23 March 2013, E.J. South, R. E. DeWalt, 5M ( INHS Insect Collection 631289) GoogleMaps . New York: Clinton Co., North Branch Great Chazy River, Moores at Wood Falls Rd. , 44.95646, -73.63919, 23 March 2016, R. E. DeWalt, 2M ( INHS: Insect Collection 659142) GoogleMaps ; Little Chazy River, Rt. 22 West Chazy , [44.82211, -73.509017], 14 March 2007, L. Myers, 2M ( CSUIC) GoogleMaps ; Salmon River, US 9 South of Plattsburgh , [44.62795, - 73.44752], 1 April 2008, M. Malchoff, 2M ( CSUIC) GoogleMaps ; Salmon River, Salmon River Rd. , 44.64010, -73.49470, 16 March 2012, L. Myers, 32M ( CSUIC) GoogleMaps ; [Saranac River], Silver Lake Rd. , [44.54532, -73.86182], 15 March 2005, L. Myers, R. Younghanz, 9L ( CSUIC) GoogleMaps ; same location, 12 March 2006, L. Myers, 2M ( CSUIC) GoogleMaps ; Saranac River, Rt. 3 & Strackville Rd. , [44.60540, -73.80239], 12 March 2007, L. Myers, 1M, 3F ( CSUIC) GoogleMaps . Essex Co., Bouquet River, Rt. 22, Willsboro , 44.36370, -73.39080, 16 March 2012, L. Myers, 6M ( CSUIC) GoogleMaps ; North Branch Bouquet River, US 9 & Trout Pond Rd. , 44.35300, -73.54378, 12 March 2007, L. Myers, J. Myers, 2F ( CSUIC) GoogleMaps . Franklin Co., Develin Brook, Rt. 11b, West of Bangor , 44.80030, -74.44540, 18 March 2008, L. Myers, R. Mowrey, 1M ( CSUIC) GoogleMaps . Hamilton Co., Sacandaga River, Jct. Rt. 8 & Rt. 30, 43.44530, -74.25244, B. Kondratieff, L. Myers, 4M ( CSUIC) GoogleMaps . Herkimer Co., West Canada Creek, Jct. Rt. 28 & Rt. 8, [43.23088, -75.08965], 12 March 2012, L. Myers, B. Kondratieff, 1M ( CSUIC) GoogleMaps . Lewis Co., East Branch Fish Creek, Osceola Rd. , Lewis , [43.46239, -75.59737], 31 March 2009, L. Myers, 2M, 3F ( CSUIC) GoogleMaps . Oneida Co., Mohawk River, Stokes Westernville Rd. , North Westernville , 43.3116, -75.3816, 18 March 2009, L. Myers, 1M ( CSUIC) GoogleMaps ; West Branch Fish Creek, Brewer Rd. , SE Camden, 43.32570, -75.71850, 19 March 2009, L. Myers, 2M ( CSUIC) GoogleMaps . Oswego Co., North Branch Salmon River , CR 17 ,

Upstream of reservoir, 43.58740, -75.8478, 31 March 2009, L. Myers, 4M, 2F ( CSUIC). St. Lawrence Co., Deer River , Rt. 11, 44.77570, -74.64880, 14 March 2009, T GoogleMaps . Mihuc, 1F ( CSUIC); Grass River, Canton at US 11, 44.59454, -75.17412, 24 March 2010, R GoogleMaps . E. DeWalt, M. Pessino, 8M, 2F ( INHS: Insect Collection 551145); Raquette River, Rt. 11, Potsdam , 44.66740, -74.98880, 14 March 2009, T GoogleMaps . Mihuc, 1M ( CSUIC). Vermont: Chittenden Co., Lamoille River , Rt. 7, Clarks Falls , Milton , 44.64060, -73.11300, 19 March 2012, L. Myers, J. Myers. 18M, 1F ( CSUIC). West Virginia: Greenbrier Co. , Greenbrier River , Anthony , [37.89595, -80.33201], 29 February 2004, L. T GoogleMaps . Miller, 5M, 2F ( CSUIC). Pocahontas Co., [North Fork], WV 28 at Green Bank , [38.41482, -79.850228], 13 January 1987, R GoogleMaps . F. Kirchner, 5L ( CSUIC); Greenbrier River, Rt. 39 at Marlinton , [38.22449, -80.09596], 7 March 1987, R GoogleMaps . F. Kirchner, 8M ( CSUIC); same location, 8 March 1988, R GoogleMaps . F. Kirchner, 7M, 2F ( CSUIC); same location, 3 March 1989, R GoogleMaps . F. Kirchner, 12L ( CSUIC) .

Adult male ( Fig. 34A View FIGURE 34 ). Forewing brachypterous. Length of forewings 1.7–2.6 mm (n = 10). Length of body 8.7–10.4 mm (n = 10). General body color brown to dark-brown.

Head ( Fig. 34A View FIGURE 34 ).Dorsum of head mostly dark-brown.Labrum pale anteriorly, brown submedial spots posteriorly. Anterior frontoclypeus light-brown. Frons brown with a dark-brown U-shaped marking with posterolateral extensions. Antenna longer than body. Scape, pedicel, and flagella yellow-brown to dark brown. Scape with a distal notch on anterior face. First flagellum subdivided at distal 1/4. Triangular raised rugosities anterolateral to lateral ocelli and ecdysial suture. Interocellar area uniformly dark-brown and slightly depressed. Occiput with dark brown rugosities. Medial areas of the frons, interocellar surface, and occiput covered with fine, pale, clothing hairs.

Thorax ( Fig. 34A View FIGURE 34 ). Pronotum subquadrate, wider than long (L 0.75X width) with posterior width marginally wider than anterior width; brown overall with darker rugosities. Outer margins of pronotal flange often pale. Disk with irregular dark rugosities. Prosternum moderately sclerotized. Meso- and metathorax brown, heavily sclerotized dorsally and moderately sclerotized ventrally. Thoracic sterna and coxae uniformly covered with short, fine clothing hairs and longer brown setae. Legs brown, generally concolorous. Femur with an incomplete mottled brown stripe on the anterodorsal and posterodorsal faces. Tibia brown; apex of tibiae with 2-stout apical spines. Tarsus brown. Legs uniformly covered with dark, short stout setae. Wings hyaline; venation yellow-brown to brown; mottling absent. Forewing brachypterous, extending to posterior margin of tergum-1; apex acutely pointed; upturned portion of forewing <1/3 total wing length. Hindwing extending beyond abdominal segment-10; pleated anal region absent.

Abdomen. Abdominal terga and sterna 1–9 uniformly brown, lightly covered with short, brown setae. Sterna 2–8 with a pair of anterior sublateral oval brown spots. Vesicle absent on sternum-9 ( Fig. 34C View FIGURE 34 ). Sternum-9 elongated into a scooped plate ( Fig. 35D View FIGURE 35 ); width slightly wider towards base; overall shape rectangular, ventrally ( Fig. 34C View FIGURE 34 ); apex square with rounded lateral margins. Dorsally, apex broadly rounded medially and enfolded anteriorly ( Fig. 35A View FIGURE 35 ); plate with numerous long setae on dorsal and ventral surfaces ( Figs 35A, D View FIGURE 35 ); plate covering sternum-10 ventrally and extending beyond.

Terminalia ( Figs 35A–E View FIGURE 35 ). Abdominal segment-10 nested within segment-9. Tergal sclerite-10 moderately sclerotized with a heavily sclerotized medial cleft; paired anterior processes absent ( Fig. 35C View FIGURE 35 ). Cercus 5–6 segmented, excluding vestigial apical segment ( Figs 35A, 35D View FIGURE 35 ), and with a small, finger-like, posteriorly directed basalcercal process covered in socketed setae and sensilla basiconica ( Figs 35A–B, 35D–E View FIGURE 35 ). Basal plate of tergum- 10 slightly produced dorsally, sclerotized with a medial furrow ( Figs 35A, 35C View FIGURE 35 ). Lateral struts present, median strut present ( Figs 35A, 35C View FIGURE 35 ). Basal bulb fused to anterior epiproct, covered in minute raised armature ( Figs 35A–C View FIGURE 35 ), 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 apex of the anterior epiproct. Anterior epiproct dorsoventrally flattened, widening laterally towards trilobed apex with rounded apices; width of medial lobe <1/3 epiproct width ( Figs 35A–B View FIGURE 35 ). Posterior epiproct prong divided near apex into dorsal and ventral processes. Apex of ventral process with a pair of bulbous lobes that are contiguous medially; sclerotized ventrally and membranous with scale-like setae dorsally ( Figs 35A–B View FIGURE 35 ). Dorsal process pouch-like, armed with posteriorly directed spine-like setae with an apical sleeve containing 2-internal eversible filaments ( Figs 35B, 35D–E View FIGURE 35 ); filament(s) generally not visible inside of basal bulb. Paraprocts subdivided into 2-parts, symmetrical anterior paraprocts and asymmetrical multi-lobed posterior paraprocts. Anterior paraproct, sub-rectangular medially directed, narrowing apically to a rounded apex ( Figs 35A–B View FIGURE 35 ). Posterior paraprocts with 3-prongs, variously fused (not visible in Figs 35A–E View FIGURE 35 ). Left outer prong broad, flat, concave posteriorly, apex scoop-shaped, directed anteriorly. Left middle prong projecting from the posterior proximal edge of outer prong, twisted, flat, lightly sclerotized, concave anteriorly, apex scoop-shaped. Left inner prong with a sclerotized ridge bearing 12-long stout golden setae, arising from the base on the posterior face of the posterior paraproct. Right outer prong, moderately sclerotized, C-shaped laterally, with a round, distally recurved apical projection; right middle prong projecting from the posterior proximal edge of the right outer prong, tubular, twisted and tapering to apex. Right inner prong a raised sclerotized ridge bearing 12-long stout golden setae.

Adult female ( Fig. 34B View FIGURE 34 ). Macropterous. Length of forewings 13.6–14.7 mm (n = 10). Length of body 12.0– 13.2 mm (n = 10). General body color brown. Overall appearance similar to male. Wings hyaline; mottling absent. Forewing without costal crossveins between humeral crossvein and apex of the subcostal vein which may be forked ( Fig. 34D View FIGURE 34 ). AA1 vein of forewing with short fine setae, a few longer setae distally ( Fig. 34F View FIGURE 34 ). Lateral margins of abdomen unsclerotized. Sternum-8 sclerotized laterally ( Fig. 34E View FIGURE 34 ). Subgenital plate concave on posterior margin ( Figs 34E View FIGURE 34 , 36A–B View FIGURE 36 ); moderately produced posteriorly ( Figs 34E View FIGURE 34 , 36A–B View FIGURE 36 ) with a moderately sclerotized triangular area medially ( Fig. 34E View FIGURE 34 ). Sternum-9 produced just beyond the apex of abdominal segment-10; free portion of sternum (length 1.0X width); uniformly covered with long setae that become longer posteriorly; lateral margins slightly narrowing to a rounded apex. Cercus 8-segmented, excluding vestigial apical segment ( Figs 34E View FIGURE 34 ; 36B View FIGURE 36 ).

Ovum. Unknown.

Mature larva ( Fig. 37A View FIGURE 37 ). Length of male body 8.7–10.9 mm (n = 5), female body 10.5–13.3 mm (n = 6). General color light-brown to 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 rarely with the head touching or approaching the abdomen apex.

Head ( Fig. 37A View FIGURE 37 ). Dorsum of head brown with brown maculations variously developed. Antelabrum pale; anterior margin with a dense brush of golden setae. Postlabrum pale. Anterior frontoclypeus pale. Frons with a brown U-shaped marking with posterolateral extensions; light-brown subrectangular markings directly anterior to lateral ocelli. Interocellar area diffusely light-brown to brown. Occipital area brown near ecdysial suture and with irregular brown rugosities. Eyes with pigmented ommatidia reduced, not reaching eye margins. A single long seta both anterior and posterior to eyes. Antennal scape brown; pedicel and flagella light-brown; dorsobasal apically inserted setae present ( Fig. 37C View FIGURE 37 ); antenna slightly shorter than body ( Fig. 37A View FIGURE 37 ).

Maxilla ( Figs 38A–B View FIGURE 38 ). Lacinia triangular with a straight inner margin. Lacinia with 2-apical, cupped teeth and 6–7 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 margin with 12-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 1/4. Galea with a dense brush of curved setae on the distal apical margin, which transition to sparse peg-like setae at the apical 2/3; a thin patch of setae on inner margin below apical setae, which extends about halfway to base. Length of galea, including apical setae, 1.3X length of lacinia; width of galea 0.8X the lacinia width. Maxillary palp with 5-segments; 1.8X length of lacinia; all palpal segments with sensilla basiconica sparsely scattered over entire surface.

Mandible. Right mandible ( Fig. 38C View FIGURE 38 ) bicuspid, outer cusp with 2–3 teeth, inner cusp with 1-tooth. Molar pad adorned with marginal rows of truncate acanthae. Palm dorsum with 6–8 dorsal sensillae adjacent to molar pad (requires focusing through the mandible) ( Fig. 38C View FIGURE 38 circle inset); 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. 38C View FIGURE 38 . Left mandible ( Fig. 38D View FIGURE 38 ) bicuspid, outer cusp with 4-teeth, inner cusp with 1-triangular tooth. Molar pad with marginal rows of rounded acanthae and long pointed acanthae (length 2X width). Ventral face of molar pad with>15 conical acanthae ( Fig. 38D View FIGURE 38 square inset). Palm dorsum with 1–2 dorsal sensillae adjacent to molar pad (requires focusing through the mandible) ( Fig. 38D View FIGURE 38 circle inset); the proximal basal corner with a marginal patch of 4-hair-like, branched setae. Ventro-apical setal patch extending from outer cusp to beyond the inner cusp basally (indicated by dotted line in Fig. 38D View FIGURE 38 ).

Thorax ( Fig. 37A View FIGURE 37 ). Pronotum marginally wider posteriorly; light-brown with faint rugosities; Length of forewing pad male = 1.0X; female = 3.0X width. Length of hindwing pad male = 2.0X; female = 1.8X width. Venter of thorax pale. Prothoracic presternum mostly glabrous with a pair of elongate lateral cervical sclerites. Prothoracic basisternum and furcasternum light-brown; spicules if present, indistinct Mesothorax with an oval prefurcasternal pit. Mesothoracic basisternum with light-brown spicules mostly concentrated medially. Furcasternal pit present between mesothoracic legs; furcasternum triangular, wider than long (length 0.5X width). Metathoracic basisterna with a pair of furcasternal pits. Anterior face of femur generally light-brown; anterior and posterior faces of the femur with scattered short stout setae ( Fig. 37D View FIGURE 37 ). Femur and tibia with a dorsal fringe of silky setae (not shown); length of femoral setae about 1.0X the width of the femur; length of tibial setae about 1.25X tibial width. Tibia light-brown; tibial callus not significantly darkened ( Fig. 37D View FIGURE 37 ). Tarsus brown with a sparse fringe of silky setae. Venter of tibia and tarsus with scattered short stout setae.

Abdomen. Dorsum of abdomen uniformly brown ( Fig. 37E View FIGURE 37 ). Posterior margins of terga with a single row of short, stout sensillae. Posterior margins of terga 8–10 with a pair of thin, erect, submedial setae. Venter of abdomen pale; sterna 1–8 with sparse sensillae that are abundant and conspicuous on sterna 7–8 ( Fig. 37F View FIGURE 37 ). Sternum-9 with an elongate plate (male = length 1.5X width; female = length 1.5X width); plate width relative to sternal width (male = 0.7X; female = 0.7X). Male plate ( Fig. 37G View FIGURE 37 ) with sides marginally wider towards posterior margin of sternum- 9, posterolateral margins convex, evenly rounded towards apex. Female plate ( Fig. 37H View FIGURE 37 ) 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 basally, becoming denser towards apex. Cercus uniformly light-brown; dorsobasal apically inserted setae present; cercus about as long as body ( Fig. 37A View FIGURE 37 ).

Diagnosis. Oemopteryx glacialis is defined in the adult male by the lack of a vesicle, brachypterous forewings, the upturned portion of forewing being <1/3 total wing length, the medial apical lobe of anterior epiproct being <1/3 epiproct width, the apical lobes of posterior epiproct being contiguous medially and the free portion of sternum-9 being rectangular ventrally. The female is distinguished by long setae not extending to the base of AA1 vein and a subgenital plate with a moderately sclerotized triangular area medially. The larvae are defined by having a darkened third tarsal segment, and abdominal sterna 7–8 with conspicuous sensillae.

Biological notes. Oemopteryx glacialis is known from the forests and uplands of the Upper Midwest, Great Lakes, Northeast region into Atlantic Canada and south to West Virginia. Elevations of collection locations range between 3 m to 841 m ASL. Based on known records O. glacialis appears to be allopatric with O. fosketti with which it is most morphologically similar. Available records indicate adults are active from late February to mid-April. Larvae have only been collected from a few streams with drainage areas ranging from 336 km 2 to 406 km 2. Harper et al. (1991) documented a univoltine fast life cycle in Quebec with direct spring hatching and subsequent larval diapause during summer. NatureServe (2024) has assigned this species a conservation rank of G4 indicating the species is at 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.

The O. leei Group