Tryella adela, 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 : 277-278

Tryella adela n.sp.

Figs. 53a,b, 75, 85, 86

Types. NORTHERN TERRITORY Holotype 3, K179857, 38 km N of Daly Waters, Stuart Hwy, 23.xii.1986, M.S. & B.J. Moulds, AM . Paratypes as follows: 13, K179858, same data as holotype, AM . 433 (one male genitalic preparation no. AB49), 1♀, Tindal, 1– 20.xii.1967, W. Vestjens; 1♀, Tindal , 14.31'S 132.22'E, 1– 20.xii.1967, W.J.M. Vestjens; all in ANIC . 1♀, Bulman Aboriginal Comm., S Arnhem Land, nr Mainoru Stn , 25.xi.1981, A. Walford- Huggins; 13, 2♀♀, Waterhouse River , Mataranka Hsd , 23.xii.1986, MBM ; 1333 (2 male genitalic preparations nos AB1, AB2), 3♀♀, same data as holotype; 333, 1♀, 10 km N of Daly Waters , 8.xii.1982, A. Walford-Huggins; all in MSM .

Other material examined. NORTHERN TERRITORY 233 (teneral), 1♀ (teneral), Tindal, 1–20.xii.1967, W. Vestjens; all in ANIC .

Etymology. Derived from the Greek adelos meaning unseen, unknown, obscure, and referring to the small size and apparent scarcity of this species.

Description

Male ( Figs. 53a, 85, 86). Head. Usually black but sometimes brownish; often black with a pair of brown spots between lateral ocelli and eyes, and on midline against posterior margin, visible only under magnification; postclypeus and anteclypeus ferruginous. Rostrum ferruginous becoming black apically but always with extreme apex dark brown; reaching or almost reaching bases of hind coxae. Antennae black or brown, usually with basal segment, and sometimes part of second segment, brown. Without extensive silver pubescence above but usually extensive below except on clypeus. Thorax. Pronotum ochraceous with a broad middorsal fascia, pale to very dark ferruginous or sometimes nearly black, this fascia spreading laterally both at its anterior end against pronotal margin to about eyes and at its posterior end against pronotal collar; pronotal collar ferruginous to nearly black but always pale anterior of lateral angles. Mesonotum ferruginous and usually very dark immediately anterior of cruciform elevation and along lateral margins above wing bases; cruciform elevation usually light brown but sometimes dark. Thorax above often lacking noticeable silver pubescence; below medium to light ferruginous and always with distinct fine silver pubescence. Wings. Hyaline. Fore wings without infuscations; venation brown, costa pale to medium ochraceous but sometimes tinted ferruginous; basal cell hyaline; basal membrane orange or orange yellow. Hind wings with a weak infuscation at the distal end of vein 2A, often extending along much of the length of 2A, sometimes also overlaying off white plaga; venation brown. Legs. Light to medium brown; without markings. Opercula. Muddy yellow, usually with narrow black edge along lateral margin; usually covered by silver pubescence not always obvious to naked eye; clearly separated exposing apex of sternite I and barely concealing tympanal cavities. Abdomen. Tergites medium to dark ferruginous, sometimes black or darkened on tergite 1 and anterior half of tergites 2, 3 and 8, occasionally so on 4–7. Sternites light brown, often with an irregular, broad, darkened midline that usually excludes sternite VIII. Abdomen above and below often with silver pubescence not always visible to naked eye. Tymbals. Usually 9 long tymbal ribs, otherwise as for generic description. Genitalia ( Figs. 85, 86). Pygofer ferruginous; upper pygofer lobes in lateral view broad and almost straight with nearly parallel sides and a broad rounded apex, in ventral view angled slightly inwards before midpoint; basal lobes with a broad webbing fusing outer and inner lobes, in lateral view outer lobe just a short finger-like projection beyond webbing. Uncal lobes scoop-like and gently upturned at their distal ends; lateral processes of uncus in lateral view small and rounded. Conjunctival claws simple, sharply pointed, directed laterally. Flabellum produced on either side into a small triangular lobe and centrally as a low rounded lobe. Palearis absent.

Female ( Fig. 53b). Colour and markings similar to male. Abdominal segment 9 brown, tending palest ventrally; dorsal beak usually black or nearly so. Ovipositor sheath black and clearly extending beyond dorsal beak.

Measurements. n = 1033, 10♀♀ (includes smallest and largest of available specimens). Length of body: male 12.4– 13.5 (13.0); female 13.4–15.4 (14.3). Length of fore wing: male 16.1–18.2 (17.3); female 16.7–20.5 (18.8). Width of head: male 4.4–5.1 (4.9); female 4.6–5.3 (4.9). Width of pronotum: male 4.6–5.1 (4.9); female 4.8–5.7 (5.2).

Distinguishing features. Within its geographic range T. adela is most likely confused with T. castanea . Where these two species are sympatric castanea usually has a fore wing length greater than 22 mm, infuscations and a pigmented basal cell. Tryella adela is normally smaller (fore wing length never reaching 22 mm), the fore wings are normally not infuscated and the fore wing basal cell is hyaline; male genital structures show clear differences and should be examined in doubtful cases.

Furthermore T. adela shows a very close resemblance to castanea from the Victoria River district of NT and to T. kauma from Queensland; adela differs from Victoria River castanea by having the fore wing basal cell hyaline instead of weakly tinted or partly tinted translucent amber, and from kauma by having the rostrum not passing the bases of the hind coxae and by lacking any brown on antennal plates on specimens with blackened heads.

Distribution ( Fig. 75). Inland tropical Northern Territory where it is known from a relatively small area bordered approximately by Katherine, Bulman Aboriginal Community in south Arnhem Land and Daly Waters. Adults have been recorded only in late November and throughout December.

Habitat. Open woodland with shrubs. Nearly all adults have been taken at light but it is more likely that they inhabit shrubs rather than trees.