Heleomicra lenis, McAlpine, 2007

McAlpine, DK, 2007, Review of the Borboroidini or Wombat Flies (Diptera: Heteromyzidae), with Reconsideration of the Status of Families Heleomyzidae and Sphaeroceridae, and Descriptions of Femoral Gland-baskets, Records of the Australian Museum 59, pp. 143-219 : 214-217

Heleomicra lenis n.sp.

Figs 155–164

Material examined. HOLOTYPE.?, New South Wales: Kanangra-Boyd National Park , 1 km N of Boyd River [or Morong Creek] bridge [1200 m], 4.x.2005, D.K.M. ( AM K219762 ). Near dead chook. Mounted on card point . PARATYPES. New South Wales: 49??, 27!!, same data as holotype, but some Sept. 2005 ( AM, ANIC, USNM) ; 5??, 4!!, Boyd River crossing, Kanangra-Boyd National Park , April 2002 –2004, B.J.D., D.K.M. ( AM) ; 5??, Mount Wilson, Blue Mountains, April , Sept. 2002 –2004 ( AM) ; 2!!, Rudy’s Road turnoff, 15 km N of Jenolan, April 2004, B.J.D. ( AM) .

Other material. Victoria: Toolangi State Forest, 31 km S of Yea ( AM, MV); 11 km E of Warburton ( AM, MV); near Mount Juliet, 9 km E of Healesville ( AM); Swan Reach ( ANIC); Lilly Pilly Track, Wilson’s Promontory ( ANIC). Tasmania: Forest Road, Orford ( AM); The Neck, Bruny Island ( AM); Mount Field National Park ( AM, TDPI); Lake Saint Clair ( ANIC); 10 mi. [c. 16 km] E of Strahan ( ANIC); Lyell Highway, Franklin–Gordon Wild Rivers National Park ( AM).

Description (male, female).Very small largely black fly with unmarked wing, superficially resembling smaller species of Borboroides .

Coloration. Postfrons black, usually becoming brownblack to tawny brown anteriorly, dull greyish-pruinescent, except on large shining black zone on each side of ocellar triangle; face tawny to tawny brown; cheek tawny-brown with grey-pruinescent zone; occipital region dull black. Antenna brownish; segment 3 with extensive tawny zone. Prelabrum greyish brown to black; palpus yellowish. Thorax black to brown-black; mesoscutum and scutellum extensively but not densely grey-brown pruinescent; mesopleuron largely shining to glossy, with greyish pruinescent posterodorsal zone of variable size and usually much smaller posteroventral such zone, the two zones generally well separated by shining or glossy area extending to posterior margin; sternopleuron smooth, glossy, except for narrow pruinescent zone on upper margin. Legs dark brown to tawny brown; femora usually darker than other parts; fore and mid coxae largely yellowish. Wing membrane slightly smoky; veins brown. Halter tawny to brown, with dull yellow capitellum. Abdomen largely black; in some females, tergites with translucent tawny-yellow areas; in female tergite 4 largely smooth and glossy, pruinescent along anterior margin, sometimes more broadly so on median line; tergites 5 and 6 densely grey-pruinescent.

Head higher than long; eye rounded, usually slightly higher than long in profile; postfrons with short setulae on anterior half; face concave; height of cheek 0.26–0.37 of height of eye; cheek with two series of setulae (including peristomial series); the following bristles present: long inner and outer vertical, shorter but strong crossed postvertical, long ocellar, two long, subequal, strongly eclinate frontoorbitals, moderate-sized vibrissae. Prelabrum of female moderately developed, that of male markedly smaller; palpus moderately short.

Thorax. Intradorsocentral setulae in two pairs of rows; mesopleuron without setulae; the following bristles present: small humeral, presutural, 1+1 notopleurals, small or poorly differentiated supra-alar, long postalar, small posterior intra-alar, 0+1 dorsocentral, two pairs of scutellars, one rather small sternopleural. Fore femur with several long, irregular posterodorsal bristles and moderately developed posteroventral ones; mid femur with one moderate-sized anterior bristle near or beyond mid-length and smaller subapical anterior and posterior bristle; hind femur of male with a distinct series of posteroventral setulae, arising from prominent basal sockets and becoming smaller and more crowded distally, without dorsal and anterodorsal bristles in either sex; fore and hind tibiae without preapical dorsal or other bristles or spurs; mid tibia with an anterior and a posteroventral subapical spur, sometimes also with slightly differentiated posterodorsal subapical bristle; hind basitarsus c. as long as fore basitarsus but slightly thicker, shorter than mid basitarsus. Wing as for genus; apical section of vein 4 2.1–2.4× as long as penultimate section.

Abdomen. Male postabdomen: protandrial sclerites as for genus ( Fig. 164); surstylus, moveable from base, subject to extension and some twisting (positional designation of parts based on position shown in Fig. 162), with posterobasal foot extending to near cercus, narrowed beyond base, distally with three prominent lobes; outer lobe tapered distally with only one, terminal setula; anterior lobe broad, with several nonseriate setulae of different sizes; posterior lobe with a series of spinescent setulae; large horseshoe-shaped hypandrial sclerite present in front of base of aedeagus, with well sclerotized anterior and lateral margins; basiphallus broader than in H. collessi ; cercus simple, undivided, with long setulae; proctiger membranous, with median posterior lobe. Female postabdominal segments progressively narrowed, extensile; tergites 6, 7, and 8 sclerotized, undivided; spiracles 1 to 6 in pleural membrane (spiracle 7 not seen but possibly present); cerci elongate ovoid, joined by membrane for part of length; spermathecae three, with black vesicles, each with long slender separate duct, which is darkly pigmented on distal part and joins a nipple-like extension of vesicle (ducts not traced to origins).

Dimensions. Total length,? 1.2–1.4 mm,! 1.3–1.8 mm; length of thorax,? 0.61–0.72 mm,! 0.67–0.82 mm; length of wing,? 1.7–2.1 mm,! 2.1–2.4 mm.

Distribution. New South Wales: cooler parts of Central Tablelands division. Victoria: probably widely distributed in eastern half of state. Tasmania: probably widely distributed.

Notes

Heleomicra lenis is exceedingly similar to H. collessi , and a full statement of specific differences is difficult because so few specimens of D. collessi are available. The differences in the cercus of the males, apparently together with details of the surstylus, indicate fairly clearly that two species are involved, and careful study of available material seems to support the significance of the distribution of pruinescence on the mesopleuron of both sexes and tergite 4 of the female in distinguishing the species. However, some individual variation in these features seems to be present. It is also possible that additional unrecognized species are present in the poorer samples.

Heleomicra lenis has sometimes been found round wombat dung baits, but the large series from the type locality was taken round old domestic fowl carcasses. In Mount Field National Park, Tasmania, I swept several specimens from a tree hollow in a fire-damaged Eucalyptus .

The specific epithet is a Latin adjective meaning smooth in reference to the smaller amount of pruinescence on the thorax and female abdomen than in H. collessi .