Bama (Bama) bipunctatum (Hendel)

McAlpine, David K., 2015, Signal Flies of the Genus Bama (Diptera: Platystomatidae) in Papua New Guinea, Records of the Australian Museum 67 (2), pp. 25-53 : 29-30

Bama (Bama) bipunctatum (Hendel)

Figs 1, 2

Euxestomoea bipunctata Hendel, 1914a: 93 , pl. 9, figs 162,

163. Hendel, 1914b: 188 (description). Malloch, 1939:

106, pl. 4, fig. 6. Bama bipunctatum (Hendel) — McAlpine, 2001: 166.

Type material. I am unclear as to the status of the type specimens of E. bipunctata . Hendel (1914a) first established this name by publication of figures of the head and wing, without any specific description. The figured specimen or specimens therefore constitute the only type specimens. Later (1914b), Hendel described the species from “ ♂ ♀ aus Neu-Guinea, S.O. [south east], Moroka, 1300 m (leg. Loria), im Mus. Civ. Genova.” This is not a clear indication of the number of specimens available to him. However, during my visits to European museums in 1973, I found one male and one female with data agreeing with Hendel’s (1914b) material coll. L.L. (Loria) in WM, now labelled “ Paratypes ”, but I could find no specimens of the species in MCG. With regard to the two WM specimens, I noted at the time that neither seemed to be a figured specimen and therefore perhaps was not a type. I now consider it more probable that Hendel’s fig. 163 is inaccurate. The type locality “Moroka” seems to be identical with Meroka, Owen Stanley Ra., on or near an upper tributary of Kemp Welch River, E of Pt Moresby, c. 9°23'S 147°37'E.

Other material examined. Central Province: 1 ♀, Sogeri Plateau (probably Itiki Numu Estate), near Port Moresby,

May 1965, T.S. ( AM); 1 ♂, 5 km S of Sirinumu Dam , 800 m , J.W.I., June 1984 ( AM). The female specimen recorded and illustrated by Malloch (Mafulu, near Woitape, L.E.C.) has not been re-examined. It was not located by Lee et al. (1956) .

Description (♂, ♀). Small to medium-sized black fly, with heavily marked wings.

Coloration. Head black to dark brown, with some grey pruinescence. Antenna tawny, becoming brown beyond base of segment 3; arista tawny basally, blackish beyond. Prelabrum dark brown; palpus predominantly tawny. Thorax black, largely shining, with slightly blue-green tinted reflections. Fore and mid coxae brown; hind coxa tawnyyellow; fore femur brown; mid femur tawny-yellow; hind femur yellow; tibiae and tarsi brown-black. Wing partly hyaline, with extensive dark brown markings ( Fig. 1 ); costal cells and some adjacent parts yellowish; pair of blackish dots within distal dark brown zone of first posterior cell present in male, absent in only available female (see Hendel, 1914a: fig. 163; and my Fig. 1 ); halter yellow with blackish capitellum (at least in male). Abdomen shining black.

Head. Postfrons almost parallel-sided, not convex anteriorly, near mid-length c. 0.33–0.35× as wide as head; height of cheek c. 1.7–1.9 of height of eye; face in profile slightly concave to mid region, not distinctly convex below; fronto-orbital bristles rather large; postvertical bristle scarcely differentiated. Antennal segment 3 narrowly rounded apically; segments 4 and 5 apparently very short (better study material needed); segment 6 with hairs relatively long for genus on most of length. Palpus moderately short.

Thorax. Mesoscutum bare and largely glossy between dorsal setulae, pubescent-pruinescent only towards lateral margins; mesopleuron almost entirely glossy, with only small trace of pruinescence; scutellum with fine pubescence on most of dorsal surface; thoracic chaetotaxy as given for B. robertsi . Fore femur with long, moderately stout posteroventral and posterodorsal bristles; mid coxa with comb of marginal setulae and rounded anteromedian lobe with non-linear group of smaller setulae. Wing ( Fig. 1 ): first costal cell largely bare; second costal cell almost uniformly microtrichose; stem vein with non-linear group of dorsal setulae; vein 2 with very slight sigmoid curvature; second section of vein 4 with sigmoid curvature; penultimate section of vein 4 almost as long as anterior crossvein, c. half as long as discal crossvein; in first basal cell, only sub-basal hyaline zone bare; second basal cell bare on c. basal half; anal cell bare, except near anal crossvein; anal crossvein with abrupt bend near mid-length.

Abdomen. Male: sternite 4 not cleft; aedeagus ( Fig. 2 ) with preglans smooth, more sclerotized than stipe but scarcely swollen and without lobe; flexible section short, with well defined sclerite; glans rather slender, subcylindrical, with membranous distal lobe rather long, broad basally, rounded apically; bulb c. 0.4× as long as glans, c. twice as long as wide; left terminal filament tapered, but slightly expanded again at apex, c. 0.8× as long as glans; right terminal filament only slightly shorter, of similar diameter except at narrowly truncate apex. Female: compound tergite 1+2 c. 0.65× as long as exposed part of tergite 3; sternites not observed.

Dimensions. Total length, ♂ 5.2 mm, ♀ 7.1 mm; length of thorax, ♂ 2.0 mm, ♀ 3.2 mm; length of wing, ♂ 4.9 mm, ♀ 7.0 mm; length of glans of aedeagus, 0.24 mm.

Notes. Hendel described this species in his genus Euxestomoea , which it somewhat resembles in wing markings and general appearance. However, the largely bare anal cell, the dorsally setulose stem vein, the one very large apical mid-tibial spur, in the male the long but unequal terminal filaments arising from a rather long bulb, and in the female the vestigial abdominal tergites 4 and 5 in contrast to the large tergite 3, are all in contrast to Euxestomoea and in agreement with Bama .

Hendel (1914a, b) illustrated and described two blackbrown dots in the distal dark zone in the first posteriormarginal cell of the wing, and these appear to be the basis of the specific epithet. These dots are present in the only male now available to me ( Fig. 1 ), but are absent in the only available female, as they are also in the female wing figured by Malloch.

Hendel described the species as having the halter yellow with black capitellum, and this is in agreement with my one available male. However Malloch described his female specimen as having the capitella (“knobs”) yellow. My female has the capitellum missing from both halteres. This character needs checking on a better series of specimens. Bama robertsi and B. divergens are the only other known species of the subgenus Bama with dark capitellum.

Figures

Figures 1, 2. Bama bipunctatum (Hendel). (1) Left wing of male, Sirinumu Dam. (2) Distal part of aedeagus, Sirinumu Dam, scale = 0.1 mm.bu, bulb; fs, flexible section of aedeagus; g, glans;lg, distal lobe of glans;pg, preglans;tf, terminal filaments.