Oecetis geniculata, Wells, 2006

Wells, Alice, 2006, A review of Australian long-horned caddisflies in the Oecetis pechana-group (Trichoptera: Leptoceridae), with descriptions of thirteen new species, Memoirs of Museum Victoria 63 (2), pp. 107-128 : 117

Oecetis geniculata sp. nov.

Figures 25, 26, 64

Material examined. Holotype. Male, NT, Litchfield National Park , Billabong, 18–19 Apr 1992, A. Wells ( ANIC).

Paratypes. NT: 21 males, 33 females, same data as for holotype ( NTM and ANIC); 17 males, 15 females, Humpty Doo , Solar Village , 9 Apr 1991, Horak and Upton ( NMV) .

Other material. Forty-five samples from the north of NT.

Diagnosis. Readily distinguished by the almost jointed appearance of the inferior appendages in ventral view, the unusually slender wings, and markings on the forewings.

Description. Male. Wings with vestiture short; forewing with a patch of scales, but scales appear to be readily dehiscent so that often specimens are collected without scales. Forewing length 4.6–5.0 mm. Abdominal segments II–IV darkly sclerotised, segment IX of moderate length, segment X sub-triangular. Genitalia, see figs 25–26. Pre-anal appendages almond-shaped. Inferior appendages stout, elongate, ridged and turned inward at about two-thirds length, giving a jointed appearance; without a basi-dorsal pouch. Phallus about 1.5 abdominal segments long, paramere straight.

Distribution. Often abundant in samples from the north-west of NT.

Etymology. The name derives from the Latin geniculatus — knotty, for the somewhat jointed appearance of the inferior appendages.

Remarks. This species is small and pale, its narrow wings lacking the usual dark markings of the pechana -group. It is commonly collected at billabongs or other stillwater bodies.