Tryella occidens, Moulds, 2003

Moulds, M. S., 2003, An Appraisal of the Cicadas of the Genus Abricta Stål and Allied Genera (Hemiptera: Auchenorrhyncha: Cicadidae), Records of the Australian Museum 55, pp. 245-304 : 292-293

Tryella occidens n.sp.

Figs. 66a,b, 100–102

Types. WESTERN AUSTRALIA— Holotype 3 (genitalic preparation no. AB23), K179834, Carnarvon, 26.ii.1977, MBM, in AM. Paratypes as follows: 433, 2♀♀, Carnarvon, 24,25,26. ii.1977, MBM; 233 (one male genitalic preparation no. AB24), Carnarvon, 4.ii.1975, 10.v.1981, K. & E. Carnaby; 13 (genitalic preparation no. AB48), 4♀♀, Lyndon R. crossing, NW Coastal Hwy, 28.ii.19184, 19.ii.1985, at light, K. & E. Carnaby; all in MSM. 13, Gascoyne R, Carnarvon, 3.iii.2001, P. Hutchinson, in PH .

Etymology. From the Latin occidens meaning in the direction of the setting sun and referring to the extreme western distribution of this species in Australia.

Description

Male ( Figs. 66a, 100, 101). Head. Black or dominantly so on most individuals, sometimes dark ferruginous, and usually with a very small muddy yellow marking on midline against posterior margin, not discernible to naked eye; postclypeus ferruginous; anteclypeus ferruginous but usually a little darker than postclypeus except along midline. Rostrum muddy yellow basally becoming black towards apex particularly on labium, but always with extreme apex dark brown; reaching to or just beyond bases of hind coxae. Antennae black or sometimes dark brown. Often bearing some silver pubescence, especially below. Thorax. Pronotum dark ferruginous, sometimes with a broad fascia along midline a little darker or a little paler than remainder; pronotal collar usually very dark ferruginous, especially at lateral angles. Mesonotum dark ferruginous, sometimes with an adjacent pair of obconical markings based on anterior margin a little paler; cruciform elevation similar in colour to majority of mesonotum. Thorax above often with some silver pubescence; below substantially covered by silver pubescence. Wings. Hyaline. Fore wings always with a bold zigzag infuscation following basal veins of apical cells 2–4 and also along the length of vein R1b forming apical cell 1; venation and costa brown; basal cell tinted brown, sometimes barely so; basal membrane dark grey to brown; costa and veins on basal half or so of wing usually with some silver pubescence, not always discernible to naked eye. Hind wings with infuscations bordering plaga along veins 2A and 3A; plaga off white, following length of vein 2A, almost the length of 3A, and the inner margin of anal lobe almost to distal end of 3A; venation muddy yellow, sometimes tending brown. Legs. Mid brown, without obvious tonal contrasts or markings. Opercula. Medium to dark grey tending yellowing or reddish brown and with little tonal variation; often bearing fine silver pubescence usually visible to naked eye; clearly separated, exposing apex of sternite I and barely concealing tympanal cavities. Abdomen. Dark ferruginous to nearly black, of even or nearly even tone but usually with tergite 2 paler laterally and tergite 8 black or nearly so along posterior margin. Sternites similar in colour to tergites although sometimes a little paler near base. Abdomen above and below usually with silver pubescence visible to naked eye. Tymbals. Usually 11 long tymbal ribs, otherwise as for generic description. Genitalia ( Figs. 100, 101). Pygofer dark ferruginous to nearly black; upper pygofer lobes in lateral view stunted, very broad and rounded, in ventral view tilted slightly inwards; basal lobe entirely lacking outer lobe, the inner lobe normal. Uncal lobes with mediodistal part of each developed into a robust hook turned outwards and upwards; lateral processes of uncus in lateral view well-developed, straight, parallel-sided, apex nearly square. Conjunctival claws simple, sharply pointed, directed dorsolaterally. Flabellum absent. Palearis a small rounded flange set on a small but prominent raised lobe situated about one quarter length of theca from its distal end.

Female ( Fig. 66b). Colour and markings similar to male. Abdominal segment 9 usually slightly paler than tergites; dorsal beak usually darker and sometimes nearly black. Ovipositor sheath ferruginous brown usually darkest towards apex; clearly extending beyond dorsal beak.

Measurements. n = 833 and 6♀♀ (includes all available specimens). Length of body: male 19.5–22.0 (20.6); female 21.0–24.0 (23.4). Length of fore wing: male 24.9–27.7 (26.5); female 25.8–29.5 (28.2). Width of head: male 7.3– 7.8 (7.5); female 7.3–8.6 (8.0). Width of pronotum: male 7.4–9.0 (8.0); female 7.9–9.1 (8.6).

Distinguishing features. This species is remarkably similar to T. noctua but can be distinguished by the colour of the postclypeus which is ferruginous in occidens but black or nearly so in noctua . However, there are major differences in male genitalia between these two species, the most significant being the direction of the conjunctival claws (outturned and partly upturned in occidens , downturned in noctua ) and the shape and position of the lateral processes of the uncus and the basal pygofer lobes (broad and adjacent in occidens , relatively slender and widely separated on noctua —compare Figs. 48 and 100).

The male genitalia of occidens clearly differ from all other Tryella species. The partially upturned conjunctival claws are unique and the upper pygofer lobes are short and rounded with a low profile.

Tryella occidens is also similar to darker individuals of T. stalkeri . The latter species lacks the black pigmentation on the hind wing adjacent to vein 3A that is always obvious on occidens .

Distribution ( Fig. 102). Far west of WesternAustralia where there are records only from around Carnarvon and the Lyndon River crossing some 150 km north of Carnarvon. Adults have been taken in February, March and May.

Habitat. Adults inhabit trees or large shrubs.