Phthiria socotrae, Greathead & Evenhuis, 2001

Greathead, D. J. & Evenhuis, N. L., 2001, Bombylioidea (Diptera: Bombyliidae; Mythicomyiidae) from the island of Sokotra, Zootaxa 14, pp. 1-11 : 7-8

Phthiria socotrae sp.nov.

Frequently in collections of Phthiria spp. females greatly outnumber males. In this instance there is only one male, here described as the holotype of the new species. It belongs to the species group with a long second flagellomere, about as long as the width of the first, which includes P. g a e d i i Wiedemann and similar species in Europe and south west Asia. The male most closely resembles that of P. subnitens Loew in that the body is entirely black to blackish­brown above but it has largely pale yellowish legs and distinct white borders to the abdominal sterna unlike P. subnitens . The female is even paler in colour than that of P. gaedii in that the cuticle is predominantly whitish and yellow in colour. However, the females are extremely variable in coloration and black areas may be greatly reduced in comparison with darker specimens.

Holotype male. Head black with grey tomentum, except on sides of face which are shining. Sparse short hairs on ocellar triangle and frons, black. More dense and longer hair on occiput and underside white. Antenna brownish­black, hairs black. Scape and pedicel as long as wide, first flagellomere slightly more than twice length of scape and pedicel combined. Spine­like second flagellomere as long as width of first. Proboscis black. Palpi black.

Thorax. Black, grey tomentose and with a pair of ill defined shining stripes on mesonotum close to the mid­dorsal line, flared posteriorly in front of scutellum also with broad ill defined shining stripes at sides.

Legs. Coxae, bases of femora and tarsi brownish­black. Remainder pale yellowbrown. Hairs white, spicules black. Pulvilli grey, as long as claws. Claws black.

Wing. Hyaline but subcostal cell opaque whitish. Veins whitish at base darker towards apex where they are blackish. Venation with r­m cross­vein at distal quarter of discal cell, origin of R4 at level of cross­vein m­m. Fringe of squama white. Halteres greyish.

Abdomen. Black, shining. Terga barely paler at posterior margins. Posterior margins of sterna with narrow white borders. Hair white. Genitalia not dissected.

Length of body, 5 mm; of proboscis, 3 mm; of wing, 4.5 mm.

Paratype females. Head whitish with whitish tomentum. Middle of occiput, ocellar triangle and usually a median stripe on frons black. Sides of face and genae shining brownish black. Hairs white. Antenna. Scape and sometimes pedicel whitish, remainder blackish, especially outer side of first flagellomere. Proboscis and palpi as holotype.

Thorax whitish with variably developed black areas which at their greatest extent include fore margin of mesonotum with extensions at midline and above humeral calli, mesonotum in front of scutellum, anepisternum, fore margin and lower part of katepisternum, meron, laterotergite and mediotergite. Dorsal surface of mesonotum composed of mostly bright yellow scale­like patches separated by fine blackish lines and with a very fine median white stripe and a pair of lateral white stripes ( Fig. 13 ). Hair white.

Legs. Pale yellow but trochanters and apices of tarsi blackened. Pulvilli and claws as holotype.

Abdomen. Whitish with anterior margins of terga and sterna blackened to a variable extent, tending to be more extensively black at midline and anterolateral corners. Upright hair white but also with minute, short and sparse decumbent black hair and rows of long black hairs at hind margins of first and eighth terga.

Length of body, 4­5.5 mm.

Types. Holotype male and 12 female paratypes from SOKOTRA: Ayhaft , cca 13°N 54°E, 15.iii.2000, K. Stástny & V. Bejcek. Holotype in NMSA. Paratypes in MBC, NMSA, BMNH, and DJG .

Figures

FIGURE 13. Phthiria socotrae sp. nov. Dorsal view of thorax to show colour pattern: heavy shading, black; light shading, yellow; unshaded white.