Aacanthocnema casuarinae (Froggatt)

Figs 6–13, 16–18, 136; Tables 1–8

Trioza casuarinae Froggatt, 1901: 284 –285, pl. xv fig. 11, pl. xvi fig. 27.

Aacanthocnema casuarinae (Froggatt), Tuthill and Taylor 1955: 252 –253, fig. 22.

Types. AUSTRALIA, New South Wales: Type series: 2 3, 1Ƥ (dried) Manly, Froggatt, 22.ix.1894, Casuarina, Type W.W.F. 1901 (ANIC); 13 (slide) [fore wing, hind leg, parameres, aedeagus], same data except Aacanthocnema casuarina (Frogg.) (Type series), body in spirit [specimen in ethanol not seen] (ANIC); nymphs (dried, slide) Type W.W.F. 1901 (ANIC); 73, 4Ƥ (dried), same data (ANIC).

Other material examined. AUSTRALIA. New South Wales: 2Ƥ (dried), McGarr's Creek, Sydney (ANIC); 1Ƥ (dried), Mittagong (ANIC); 33, 3Ƥ (dried), Sydney (ANIC); 53, 9Ƥ (dried), Sweetwater, Kain (ANIC); 5 3, 6 Ƥ (slide), Tolwong, NNE Nettiga (AM). Tasmania: 1 3, 1 Ƥ (slide) E Queenstown (ANIC).

Description. Adult (Figs 6–12). Colour [from dried specimens]: Male: general colour ochraceous to dark brown. Vertex dark brown; genal processes white to pale cream; antennal segments 1–2 brown to dark brown; segment 3 brown, darker apically; segments 4–10 progressively dark brown to black; pronotum with a pair of dark brown to black longitudinal submedial stripes; mesopraescutum darker laterally; mesoscutum and mesoscutellum dark brown; wings clear except for brown infuscation along veins R+M+Cu, M, M1+2, M3+4, Cu, Cu1a, Cu1b and distal portion of Rs; legs with dorsal dark brown infuscation; distal tarsal segments dark brown to black; abdominal tergites dark brown to black; proctiger, subgenital plate and parameres brown to dark brown. Female: as for male, except paler: vertex with a pair of brown markings in vicinity of fovea; pronotum with a pair of brown to dark brown longitudinal submedial stripes; mesopraescutum with a pair of brown submedial markings; mesoscutellum with a pair of orange-brown to brown longitudinal stripes; proctiger brown with dark brown infuscation in proximity to circum-anal pore ring and dark brown to black at apex; subgenital plate with dark brown apex.

Structure: measurements and ratios as in Tables 1–5. Antennae short, 1.33–1.47 times width of head; genal processes moderately long, 0.65–0.84 times length of vertex, conical, apices separated, little-divergent; anterior margin of vertex rounded from dorsal aspect, delineated from genal processes by prominent ridge; vertex with distinct medial suture; pronotum with prominent anterior, medial node; thorax weakly arched, head wider than pronotum and mesoscutum, fore wings elongate with broadly rounded apex; Rs short, terminating well short of wing apex; vein M1+2 terminating little short of wing apex; cell m1 short, broadly triangular, m1 cell value 0.93–1.42; cell cu1 short triangular, cu1 cell value 1.15–1.52; vein Cu1a strongly arched (veins Cu1a and M proximal at closest point); radular areas elongate in cells m1 and m2 and cu1; male terminalia as in Figs 16–17; proctiger without lateral expansions; parameres short, broad basally from lateral aspect, weakly curved inward towards apices. Female terminalia as in Fig 18; proctiger broadly rounded, dorsal margin rather flat from lateral aspect; subgenital plate short, broadly rounded, triangular from lateral aspect.

Nymph (Fig 13): Measurements and ratios as in Tables 6–7. Body brown with dark brown markings. Eyes reddish brown; head with submedial dark brown markings in vicinity of fovea; thorax with meso-and metathoracic depressions dark brown to black; lateral margins of fore wing pads dark brown; caudal plate with dark brown infuscation submedially and delineating margins of abdominal tergites. Body elongate; anterior margin of head rounded; dorsum of body with a distinct medial longitudinal ridge; caudal plate narrow with hind margin rounded.

Distribution. Recorded from Sydney and adjacent localities in the Blue Mountains. Two specimens from a single locality near Queenstown in montane western Tasmania are tentatively attributed to Aa. casuarinae (Fig. 136).

Host plant. Froggatt (1901) recorded the host as Casuarina distyla (junior synonym of Allocasuarina distyla (Vent.) L. Johnson). Allocasuarina distyla occurs as a dioecious shrub 1–3 m high in tall heath on sandstone ridges from Port Stephens to east of Cooma in south-western New South Wales. Specimens of Aa. casuarinae collected from Eucalyptus simmondsi (junior synonym of E. ambigua A.Cunn ex DC.) in Tasmania were undoubtedly from nearby Allocasuarina, although A. distyla is not recorded from Tasmania (Wilson & Johnson 1989).

Comments. Aacanthocnema casuarinae is very close morphologically to Aa. burckhardti (see Comments under Aa. burckhardti for diagnoses).