Nisitrus Saussure, 1878

Robillard, Tony & Tan, Ming Kai, 2013, A Taxonomic Review Of Common But Little Known Crickets From Singapore And The Philippines (Insecta: Orthoptera: Eneopterinae), Raffles Bulletin of Zoology 61 (2), pp. 705-725 : 707

Genus Nisitrus Saussure, 1878

Nisitra Walker, 1869: 91 ; Chopard, 1940: 199

Nisitrus Saussure, 1878: 511 , 522> Nomen novum for Nisitra Walker. Chopard, 1968: 352 ; Desutter-Grandcolas, 1990; Otte, 1994: 67 > Eneopteridae : Eneopterinae . Preston-Mafham, 2000: 2241 > behaviour. Robillard & Desutter-Grandcolas, 2004a: 276; 2004b: 578; 2004c: 304; 2006: 644; 2011: 637> phylogeny and acoustic evolution. Robillard et al., 2007: 1265 > acoustics. Robillard & Desutter-Grandcolas, 2008: 67> Nisitrini tribe. Desutter-Grandcolas et al., 2010: 616 > cerci evolution. Nattier et al., 2011: 2201 > phylogeny and molecular dating. Eades et al., 2012 > Orthoptera species file online.

Type species. — Nisitrus vittatus (Haan, 1942)

Diagnosis. — Among the Eneopterinae genera, Nisitrus is characterised by an elegant, wasp-like, slender and colourful body ( Figs. 1 , 3 , 8 ). Size average for subfamily. Colouration vivid, dominantly yellow, whitish and black with species specific patterns. Characteristic head shape with narrow fastigium and large prominent yellow green eyes with dorso-ventral black stripes. Pronotum setose, square shaped to slightly trapezoidal, usually bisinuated posteriorly. Metanotum with large glandular structures in males, made of a wide pit on scutum and a pair of posterior pits on scutellum, with glandular pores mostly organised by groups of 2 or 3 ( Fig. 2 ). FWs more or less as long as abdomen. Male Nisitrus show modified FW venation and characteristic glossy transparency. Hind wings longer than FWs, bicoloured in some species. Legs long and thin, FIII with a characteristic narrowed area before knee. Other general traits: TI with two tympana, inner one slit-like, covered by a swollen cuticular expansion; outer tympanum oval, its membrane transversally plicate in dorsal half. TI with three apical spurs; outer dorsal spur missing. TII with four apical spurs, inner longest. TIII with three inner and three outer apical spurs, median longest on each side; four pairs of subapical spurs, inner and outer spurs almost straight, their apex hook-like; TIII serrulate over whole length and slightly furrowed dorsally. Tarsomeres III-1 with one row of dorsal spines on external edge in addition to apical spines. Apical claws of legs slightly indented. Both males and females show characteristic genitalia: male genitalia with membranous and setose lophi well individualised; female copulatory papilla conical, apex generally sclerotised and pointed ( Fig. 7 ). Nisitrus is very close morphologically to Paranisitra Chopard, 1925 (revised by Gorochov, 2009), the second genus among the Nisitrini tribe (Robillard & Desutter- Grandcolas, 2008). Paranisitra is mostly characterised by lack of wings in both sexes, but except for this, it shares with Nisitrus its general body shape, long thin legs with indented claws, colouration with yellow and black, head shape and the general structure of male and female genitalia. Nisitrus is less easy to relate to other clades of Eneopterinae .

Figures

Fig. 1. Habitus of Nisitrus vittatus, drawing by Vanessa Damianthe & Gilbert Hodebert (MNHN). Male specimen from Singapore. Scale bar = 5 mm.

Fig. 3. Nisitrus vittatus: A, B, male; C, D, female. A, C, dorsal view; B, D, lateral view. Scale bar = 1 cm.

Fig. 8. Nisitrus vittatus: A, female on low vegetation along track in McRitchie reservoir park in Singapore; B, couple mating at night along Wallace Trail, Hindhede Nature Park, Singapore; C, subadult specimen in Wallace Trail, Hindhede Nature Park, Singapore.

Fig. 2. Metanotal glandular structures in Nisitrus vittatus. A, glandular pits (drawing by G. Hodebert (MNHN) modified from Robillard & Desutter-Grandcolas, 2004a); B, SEM view of glandular pores on scutum; C, SEM view of glandular pores on scutellum. Scale bars = 5 mm (A), 1 μm (B), 10 μm (C).

Fig. 7. Female genitalia: A–C, apex of ovipositor; D–F, copulatory papilla. A, D, Nisitrus vittatus; B, E, Lebinthus bitaeniatus; C, F, Lebinthus luae. Scale bars = 1 mm.