Physiphora allomma Speiser 1914

Physiphora allomma (Speiser 1914)

Figures 41–52.

Chrysomyza allomma Speiser, 1914: 16; Physiphora allomma: Steyskal, 1980: 576.

Material. Type. Holotype ♀: [Cameroun:] “Dschang, Oktober 1912 ” not located, apparently destroyed during WWII. Non-type. Ethiopia: Wushwush Saum, 36º 05.17E 07º 18.59N, h= 1988m, Trockenrasen, Streifnetz, 6, 10.12.2014, 3♂, 1♀ (H.-J.Flügel) (HJFC; SIZK); South Africa: W Cape, Cape Town, 33º56′S 18º28′E, larvae infesting growth tip of date palm, 19. v.2008, 6 ♂, 3♀, 3 puparia (G. Tribe) (SANC; SIZK); Namibia: West Kaprivi Park, Okavanga River Susuwe, 17º45′ 37″S 23º20′56″E, Malaise trap, dry woodland, 28.ix–2. x.1998, 1 ♂ (A. Kirk- Spriggs); Mahango Game Park, Okavango River at 18º13′ 19″S 21º45′10″E, Malaise trap, dry woodland, 1♀ (Kirk- Spriggs, Pape & Hauwanga) (NICW).

Diagnosis. This species differs from all other species of the genus by the combination of almost entirely black head, dull black thorax with faint blue or violet tinge, white fore basitarsomere with dark basal (!) and apical 0.2 of its length, and wing with widely opened cell r4+5 and brown veins. Superficially similar P. hendeli sp. n., P. rugosa sp. n., and P. tarsata, which sometimes may have dull black thorax with faint blue tinge, can be easily differentiated from it by the cell r4+5 narrowly closed, veins light yellow, fore basitarsomere yellow at base, and frons deeply wrinkled or pitted (smooth in P. allomma). P. aperta, P. longicornis, and P. violacea sharing with P. allomma black mesonotum with blue or violet tinge, are shining, with sparsely and weakly wrinkled thorax, whereas in P. allomma it is densely rugulose and dull. P. allomma and P. aperta (from Solomon Islands) share widely opened cell r4+5 and brown veins, differing mostly by black or brown frons and different ratio of the sections of costal vein between R4+5 and M and between R2+3 and R4+5 (see Key and Figs. 45 and 59).

Description. Head (Figs. 42–44) black. Frons 1.2 times as long as wide, black, at anterior margin sometimes brown, shining, sparsely and finely, almost inconspicuously setulose, with round parafrontal microtichose spots and two pairs of calluses (oval swellings) posterior to its middle and slightly concave anterior half. Vertical plates black, with dark blue sheen, bearing 2 pairs of black, short, slightly reclinate orbital setae. Ocellar triangle black.

Face black to dark brown, facial carina sharply delimited, dorsal half brown and black, medially with triangular microtrichose area narrowly separated from microtrichose antennal grooves. Lunule and facial ridge, parafacial and gena black or, rarely, brown, gena 1/3 times as high as eye; only parafacial with narrow white microtrichose stripe along anteroventral eye margin. Epistome entirely black. Occiput black. Medial vertical seta half as long as frons width, 1.3 times as long as lateral vertical and 3–4 times as long as ocellar, orbital and postocellar setae. Antenna brown to black; flagellomere 1 rounded apically, 1.5 times as long as wide, greyish microtrichose; arista bare, brown in basal 1/6, remainder black. Clypeus brown to black. Palp brown to black. Mouthparts black.

Thorax (Fig. 41). Scutum and scutellum black, with dull green metallic sheen, finely rugulose, except antepronotum and posterior surface of postpronotal lobe, as well as pleura strongly shining; posterodorsal part of anepisternum shagreened; supra-alar area and tympanal fossa matt brown to black, postscutellum black, gray microtrichose; postero-ventral margin of scutellum without microtrichose area. Mesonotal scutum without medial row of setulae, acrostichal and dorsocentral setae; only poorly visible dorsocentral and postsutural intra-alar setulae present; all setae very fine and short, black. One postprononal, 2 postsutural supra-alar, one intra-alar and one postalar setae strong, black.

Scutellum transversely shagreened, with faint deep blue reflection, with very fine and short black setulae and 2 pairs of black scutellar setae.

Wing. Entirely hyaline, with brown veins; cell r4+5 conspicuously open, section of costal vein between R4+5 and M longer than half of crossvein r-m and less than half (0.25–0.3) times as long as section of costal vein between R2+3 and R4+5 (Fig. 45). postero-apical extension of cell cup 1.3 times as long as vein A1+CuA2, and 3 times as long as transverse section of vein CuA2. Length: 3.0–4.9 mm.

Legs. Black except fore tarsus with basitarsomere creamy yellow in medial portion, and black in basal and apical one-fifth, mid- and hind tarsi yellow except apical tarsomeres black; all setae black; fore femur posteroventrally with 3–5 thickened, but rather short setae in apical half.

Abdomen. Both tergites and sternites black, finely rugulose, with bluish reflection; all setulae black; abdominal tergite 1 basally grey microtrichose; female abdominal tergite 2 with pair of dimple-like structures laterally.

Male postabdomen brown to black; epandrium as on Figs. 48–49, phallus with stipe at most as long as preglans and glans; preglans with chain of sharp spinules (Fig. 46 a) and big black spur distally of caecum (Fig. 46 b); glans as on Figs. 47, with at least two wide-based, sharply pointed lobes and one narrow claw-like lobe.

Female terminalia: eversible membrane (Fig. 50) with two pairs of long taeniae and membrane between them cowered by fine monodentate scales; aculeus (Fig. 51) 7 times as long as wide at base; 3 spherical spermathecae (Fig. 52).

Distribution: Ethiopia to Cameroon, Namibia and South Africa.

Biology. Larvae feed in rotting date palm stems (possibly damaged by the palm weevil larvae).

Remarks. Rare in collections; further comparative study of this species and P. aperta is needed.