Dayus euryphaessus ( Kirkaldy, 1907 )

Webb, Michael D. & Xu, Ye, 2022, Review of the “ red ” Empoascini leafhoppers in the genera Baguoidea Mahmood, 1967, Dayus Mahmood, 1967 and Homa Distant, 1908 (Hemiptera, Cicadellidae, Typhlocybinae) from Asia and the West Pacific, Zoosystema 44 (22), pp. 549-563 : 552-555

Dayus euryphaessus ( Kirkaldy, 1907)

( Fig. 2 A-F)

Cicadula euryphaessa Kirkaldy, 1907: 68 ; 1908: 383.

Empoasca euryphaessa – Linnavuori 1960a: 17, Fig. 5f , h-j. — Evans 1966: 266 (misidentification(?) see Remarks below). — Wilson 2009: 46.

Empoasca euryphaessa rubrocincta Linnavuori, 1960a: 18 . — Dworakowska 1971: 501. — Wilson 2009: 46.

Dayus euryphaessus – Dworakowska 1971: 501.

DISTRIBUTION. — Fiji, Australia (?) see Remarks below.

MATERIAL EXAMINED. — Fiji • 1 ♂; Labasa; R. Veitch; VII.1921; NHM • 1♀; Lautoka; W. Greenwood; 6.XII.1921; breeding on leaves of Glochidion sp. ; NHM • 1 ♀; Loloti; W. Greenwood; 19.XII.1920; NHM .

REMARKS

This species was described from an unknown number of specimens (syntypic) from Fiji with data: “ Viti Levu, Rewa (Mar.-Apr.) Navna (Feb. Muir’s No. 53) on a native tree, also on Saccarum officinarum ” (Sugarcane) (BPBM) . The data label on an imaged specimen seen (BPBM) labelled both “type” and “ Holotype ”, is as follows: “ Fiji Is 1905 [printed] 53[handwritten]” ( Fig. 2A, B ). An image of four other syntype series specimens (labelled “ Paratype ”) has been seen (BPBM). In its description Kirkaldy noted the following: “Allied to C. rufa (Melichar) [= Dayus rufus ] but the head is longer, pronotum shorter, legs pale, etc. Bright scarlet, vertex pale testaceous with a medio-longitudinal suffused scarlet stripe, which forks at the base of the frons and extends all over the face suffusedly (sometimes the red stripe is obsolete at the fork, the frons then being entirely pale, only the genae and the clypeus, etc., red.)”.

Dworakowska (1971: 501) noted her placement of D. euryphaessus in Dayus was based on the original description, presumably its colour, proportions of the head and thorax and venation. In the original description it was also noted that the venation was similar to Baguoidea rufa and this is confirmed by Linnavuori’s (1960a) redescription, which reads “third apical cell of elytra triangular and stalked” and the material examined here. However, the species is only tentatively retained in Dayus as the male genitalia show certain differences to that genus, i.e., the pygofer lacks a caudo-dorsal lobe, the subgenital plate lacks a basal setal group and the aedeagal shaft is very short without processes, all characters also found in the similar D. upoluana , although the aedeagus and connective are fused ( Fig. 2N ) and dorsal abdominal apodemes are present ( Fig. 2I ), as in other congeners.

Linnavuori (1960a) identified (and figured) D. euryphaessus from 29 specimens from Fiji, Lami, as part of a collection from Fiji sent to him by BPBM (see Introduction in Linnavuori 1960a) and not the type series, also BPBM (see above). The identification is however considered correct based on the distinctive marking of the species. It is also worth noting that Linnavuori’s figure of the aedeagus is in lateral view, but its attached connective is shown in dorsal view, while his figure of long sternal abdominal apodemes are dorsal, as in other Dayus species.

Linnavuori (1960a) also described a new subspecies ( Empoasca euryphaessa rubrocincta ) from the holotype and allotype (BPBM) ( Fig. 2 C-F) and one paratype in his own collection, from the same locality as the nominate subspecies, Fiji, Lami. It seems strange that Linnavuori (1960a), when referring to his new subspecies, should say “As the nominate form…” as he described the red marking of the two subspecies differently, confirmed by the images reproduced here ( Fig. 2A, C, E ). However, his observation that the male genitalia were the same in the two subspecies, and their same type locality, suggests they are the same taxon with unaccountably different markings. In synonymising the two, Dworakowska (1971) noted the type-series of Empoasca euryphaessa rubrocincta had been studied but from personal communication a single specimen was studied.

The record of the species from Australia (Kuranda) by Evans (1966: 266), could be incorrect and could be the specimen of Homa haematoptila , from Kuranda, noted below.

Figures

FIG. 2. — Dayus Mahmood, 1967 species: A-F, Dayus euryphaessus (Kirkaldy,1907),A, B, holotype,dorsal habitus and labels respectively;C-F, types Empoasca euryphaessa rubrocincta Linnavuori,1960, C, D, allotype,dorsal habitus and labels respectively,E, F, holotype,dorsal habitus and labels respectively;G-N, Dayus upoluanus (Osborn,1934),G, dorsal habitus of female paratype;H, labels of same; I, male basal dorsal apodemes;J, male pygofer,lateral view;K subgenital plate, ventral view; L, Xth segment, ventral view; M, aedeagus, lateral view; N, aedeagus, connective and style, ventral view. Scale bars: A, C, E, 0,75 mm; G, 2 mm.

FIG. 5. — Homa sinensis Qin & Zhang, 2011: A, head and thorax, dorsal view; B, same lateral view; C, face; D, forewing; E, hind wing; F, male genital capsule, lateral view; G, male pygofer, dorsal view; H, male pygofer, lateral view; I, male basal abdominal apodemes; J, male anal tube process, lateral view; K, aedeagus and connective, dorsal view; L, aedeagus and connective, lateral view; M, subgenital plate, ventral view; N, style. Reproduced from Qin et al. (2011, figs 1-13), with permission from copyright holder.