Wormaldia hamata 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 : 31-33

Wormaldia hamata Denning

Figures 46–52, 131.

Wormaldia hamata Denning 1951: 158 , figs. 2 A, B, male, California, USA (CAS); Ross 1956: 38, 61, 62, figs. 69 A–C; Denning 1956a: 79; Denning 1956b: 248, fig. 10: 16D; Fischer 1971: 191; Armitage 1996: [work not paginated].

Denning (1951) placed this species within subgroup 3 of the W. moesta Group of Ross (1949). Subsequently, Ross (1956) reconsidered his former species group proposal and transferred W. hamata to the W. anilla Group. In 1996, Armitage modified Ross’s species group proposal and relocated W. hamata within the W. thyria Group (Table 1).

The genitalia of this species, Wormaldia gesugta Schmid (1968) , W. laona Denning (1989) , W. mohri ( Ross 1948) , W. oconee Morse (1989) , and W. thyria Denning (1950) 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 Wormaldia . However, W. laona , W. mohri , and W. oconee can be separated from W. hamata , W. gesugta , and W. thyria , as detailed in the diagnoses of the first three species. This species can be separated from W. gesugta and W. thyria by the shapes of tergum VIII, segment IX, and the inferior appendage. Tergum VIII in W. hamata is strongly projected subtriangularly, beyond the middle of tergum X, and narrow and truncate posteromesally. Tergum VIII in W. gesugta is subtriangularly projected, reaching the middle of tergum X, and narrow and rounded posteromesally; in W. thyria it is slightly projected convexly, barely surpassing the bases of tergum X and superior appendages, and broad and slightly straight posteromesally. When viewed laterally, segment IX in W. hamata is acutely convex anteromedially. Segment IX in W. gesugta is convex anteriorly; in W. thyria it is broad with a strong projection convexly elongate anteromedially. Sternum IX in W. hamata is straight posteriorly. Sternum IX in W. gesugta is very weakly sinuous posteriorly; in W. thyria it has a deep, wide, and V-shaped emargination posteriorly. When viewed laterally, the basal segment of the inferior appendage in W. hamata and 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 male forewing 5 mm (holotype). Head brown, with lighter setae. Antenna long, slender, yellowish, with small, lighter setae. Maxillary palps yellowish, with lighter setae. Labial palps yellowish, with lighter setae. Dorsum of thorax brown. Legs yellowish, with small, lighter setae. Forewing yellowish, covered with fine, small, brown setae, with apical forks I, II, III, and V present ( Fig. 51). Hind wing translucent, with very few fine, small, brown setae, with apical forks I, II, III, and V present ( Fig. 52).

Male genitalia ( Figs. 46–50). Sternum VII with prominent, broad, convexly triangular, posteromesal process strongly elongate, about 0.5 times length of sternum VIII. Tergum VIII subtriangular in appearance, strongly projected posteriorly, beyond middle of tergum X, narrowest and slightly truncate posteromesally; when viewed laterally, hood-shaped, sinuous dorsally, slightly concave posteriorly, with posterodorsal corner rounded apically. Sternum VIII with slight, convex, posteromesal process, about 0.2 times length of posteromesal process of sternum VII. Segment IX, when viewed dorsally, deeply concave anteriorly; when viewed laterally, slender and nearly subrectangular in appearance, acutely convex anteriorly, relatively straight posteriorly; when viewed ventrally, concave anteriorly, straight posteriorly. Segment X, when viewed dorsally, triangularly elongate, narrowest and rounded apically; when viewed laterally, slender, slightly pointed apically. Superior appendages digitate; when viewed dorsally, parallel with segment X, elongate, bulged medially, rounded apically; when viewed laterally, shorter than segment X, subovally elongate posteromedially. 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, narrower than basal segment, wide and rounded posteriorly; when viewed dorsally, apical segment as in ventral view, when viewed ventrally, basal segments paired, united for about their anterior threefifths, separated posteromesally by a wide, moderately deep, V-shaped emargination, each basal segment stout, widest medially, with outer margin slightly convexly curved anteriorly, apical segment slender, subtriangularly elongate, narrowest and subovate posteriorly, with elongate and apicolateral patch of short, thin, black, spine-shaped setae on inner margin. Phallus, when viewed laterally, pistol-shaped, widest basally, tapering from middle to apex, membranous apically, very lightly sclerotized, with many small, visible, internal sclerites ( Fig. 50), surrounded by highly convulated membranes.

Material examined. USA: California: Holotype: Male, Trinity Co.: Hayden Flats , Trinity River , 30.vii.1950, 1200 ft [= 366 m], C.P. Alexander (in alcohol, CAS).

Distribution. USA: CA.