Wormaldia thyria Denning

Muñoz-Quesada, Fernando J. & Holzenthal, Ralph W., 2008, Revision of the Nearctic species of the caddisfly genus Wormaldia McLachlan (Trichoptera: Philopotamidae), Zootaxa 1838, pp. 1-75 : 61-62

Wormaldia thyria Denning

Figures 122–128, 131

Wormaldia thyria Denning 1950: 98 , pl. II, figs. 3, 3 A, B, male, North Carolina, USA (CAS); Ross 1956: 38, 61, 62, figs. 68 A–C; Denning 1956a: 79; Fischer 1971: 199; Frazer et al. 1991: 19; Armitage 1996: [work not paginated].

Denning (1950) placed this species within subgroup 3 of the W. moesta Group established by Ross (1949). However, Ross (1956) redefined his former species group proposal and transferred W. thyria to the W. anilla Group. Finally, Armitage (1996) placed this species within the W. thyria Group (Table 1).

The genitalia of this species, Wormaldia gesugta Schmid (1968) , W. hamata Denning (1951) , W. laona Denning (1989) , W. mohri ( Ross 1948) , and W. oconee Morse (1989) are similar in having tergum VIII strongly projected posteriorly, when viewed laterally it simulates a hood, which differentiates these six species from the other Nearctic species of Wormaldia . However, W. hamata , W. laona , W. mohri , and W. oconee can be recognized from W. gesugta and W. thyria , as detailed in the diagnoses of the first three species. Finally, it differs from W. gesugta by the shapes of tergum VIII, segment IX, and the inferior appendage. Tergum VIII in W. thyria is slightly projected convexly, barely surpassing the bases of tergum X and superior appendages, and broad and slightly straight posteromesally. Tergum VIII in W. gesugta is subtriangularly projected, reaching the middle of tergum X, and narrow and rounded posteromesally. When viewed laterally, segment IX in W. thyria has a broad and strong projection convexly elongate anteromedially. Segment IX in W. gesugta is convex anteriorly. Sternum IX in W. thyria has a deep, wide, and V-shaped emargination posteriorly. Sternum IX in W. gesugta is very weakly sinuous posteriorly. When viewed laterally, the basal segment of the inferior appendage in W. thyria is straight ventrally, elongate and equal in length to the apical segment. The basal segment of the inferior appendage in W. gesugta is convex ventrally, weakly elongate, and clearly shorter than the apical segment.

Adult (in alcohol). Length of forewing 5 mm (holotype). Head brown, with lighter setae. Antenna long, slender, brown, with small, lighter setae. Maxillary palps yellowish, with lighter setae. Labial palps yellowish, with lighter setae. Dorsum of thorax brown. Legs brown, with small, lighter setae. Forewing yellowish, covered with fine, small, brown setae, with apical forks I, II, III, and V present ( Fig. 127). Hind wing translucent, with very few fine, small, brown setae, with apical forks I, II, III, and V present ( Fig. 128).

Male genitalia ( Figs. 122–126). Sternum VII with prominent, broad, convexly subtriangular, posteromesal process strongly elongate, about 0.5 times length of sternum VIII. Tergum VIII subtriangular in appearance, convexly projected posteriorly, slightly surpassing bases of tergum X and superior appendages, broad and slightly straight posteromesally; when viewed laterally, hood-shaped, sinuous dorsally, posterior margin sinuous, with posterodorsal corner widely rounded apically. Sternum VIII with slight, wide, convex, posteromesal process, noticeably smaller than posteromesal process of sternum VII. Segment IX, when viewed dorsally, deeply concave anteriorly; when viewed laterally, broad, nearly subtriangular in appearance, with broad, strong projection convexly elongate anteriorly, convex posteriorly; when viewed ventrally, with shallow and broad emargination anteriorly, with wide, deep, V-shaped, posterior emargination. Segment X, when viewed dorsally, triangularly elongate, with minute, stout, spine-shaped processes lateromedially and mesoapically, narrowest and rounded apically; when viewed laterally, narrowly rounded apically. Superior appendages digitate; when viewed dorsally, parallel with segment X, stout, elongate, rounded apically; when viewed laterally, nearly equal in length to segment X, tubularly elongate. Inferior appendages two segmented; when viewed laterally, basal segment stout, subrectangular, elongate, broadest medially, convex dorsally, straight ventrally, apical segment stout, rectangular, tubularly elongate, nearly equal in length and narrower than basal segment, slightly concave medially, rounded and slightly widened posteriorly; when viewed dorsally, apical segment slender, tubularly elongate, rounded posteriorly, with short, black, spine-shaped and peg-shaped setae scarcely medially and in rounded and apicolateral patch on inner margin; when viewed ventrally, basal segments paired, united for about their anterior halves, separated posteromesally by a deep and V-shaped emargination, each basal segment stout, slightly widest medially, with outer margin slightly convex, apical segment as when viewed dorsally. Phallus, when viewed laterally, pistol-shaped, widest basally, tapering from middle to apex, membranous apically, very lightly sclerotized, when viewed dorsally, with four visible, slender, elongate, spine-shaped, internal sclerites ( Fig. 126).

Material examined. USA: North Carolina: Holotype: Male, [Henderson Co., (?)]: Neels Creek , Game Refuge , Mt. Mitchell , 30.v.1946, J.F. Hanson (in alcohol, CAS).

Distribution. USA: AL, NC, SC, TN, VA.