Bama (Bama) flavifrons, McAlpine, 2015

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 : 36-38

Bama (Bama) flavifrons n.sp.

Fig. 21

Type material. Holotype ♀ (unique). Morobe Province: Upper Stony Logging Area, near Bulolo [near 7°15'S 146°40'E], 27.vii.1979, H.R., under Euphorbia leaf ( AM K352855 ). On micropin through polyporus.

Description (♀, ♂ unknown). Moderately small, largely dark fly of moderate proportions, with heavily marked wing.

Coloration. Head: postfrons yellow, with small black fronto-orbital and ocellar zones posteriorly; face and cheekregion tawny brown; occipital region tawny, becoming blackish towards vertex, with silvery-pruinescent postocular zone. Antenna tawny; arista tawny-brown. Prelabrum tawny-brown; palpus tawny, with brownish apex. Thorax predominantly black; dense fine setulae on mesoscutum pale yellowish. Fore leg dark brown; mid and hind femora yellow; mid and hind tibiae and tarsi largely tawny. Wing with first costal cell pale tawny, second costal cell pale tawny, becoming slightly darker basally; dark brown markings otherwise as shown in Fig. 21 ; halter yellow.Abdomen black.

Head. Postfrons almost parallel-sided, nowhere gibbous, near mid-length c. 0.37× as wide as head; height of cheek c. 0.22 of height of eye; face in profile slightly concave on greater part of surface, almost flat on shallow ventral zone; fronto-orbital bristles moderately large; ocellar and postvertical bristles rather small but distinct, latter slightly divergent. Antennal segment 3 c. twice as long as deep; segment 4 very short; segment 5 rounded, its length apparently less than its diameter; segment 6 gradually tapered, with well-developed pubescence on whole length, becoming sparser apically. Prelabrum moderately developed, with lower margin prominent; palpus moderately long and slender.

Thorax. Mesoscutum minutely pruinescent between setulae on almost entire dorsal surface; scutellum minutely pubescent on entire dorsal surface; mesopleuron densely pruinescent on slightly more than posterior half; dorsocentral and prescutellar acrostichal bristles large. Fore femur with large, stout posteroventral bristles on distal half and moderately large posterodorsal bristles; mid coxa with short anteromedial lobe and dense series of large and small marginal setulae. Wing: first costal cell very finely microtrichose; second costal cell more obviously microtrichose; stem vein with a single series of dorsal setulae; vein 2 with only very slight sigmoid curvature, from near its base more evenly divergent from vein 3 than in most other species; second section of vein 4 with slight sigmoid curvature; penultimate section of vein 4 c. half as long as discal crossvein; first basal cell with sub-basal (but not distal) hyaline zone largely bare; second basal cell bare on c. basal two thirds; anal cell bare except on small apical zone; discal crossvein with almost even curvature, its posterodistal angle much more acute than anterodistal angle; anal crossvein curved only on c. anterior half, almost straight posteriorly.

Abdomen. Compound tergite 1+2 c. half as long as tergite 3 (accurate measurement not possible); sternite 1 apparently broad; sternites 2, 3 and 4 moderately large; sternites 5 and 6 shorter, but less reduced than in most other species.

Dimensions. Total length, 5.2 mm; length of thorax, 2.4 mm; length of wing, 6.1 mm.

Notes. Bama flavifrons differs from other species of the genus in the very extensive covering of fine microtrichia or pruinescence on almost the entire mesoscutum. This feature is probably only detectable in clean, dry specimens. The wing pattern somewhat resembles that of B. robertsi , though not in detail, and the predominantly yellow postfrons should prove distinctive.

The specific epithet is a Latin compound noun referring to the last-mentioned feature.

Figures

Fig. 21. Bama flavifrons n.sp., holotype female.