Hexatoma (Eriocera) metallica Schiner, 1868

Billingham, Zacariah D. & Theischinger, Gunther, 2022, New and Poorly Known Species of Crane Flies (Diptera: Limoniidae) from New South Wales, Australia, Records of the Australian Museum (Rec. Aust. Mus.) 74 (1), pp. 19-40 : 28

Hexatoma (Eriocera) metallica Schiner, 1868

Figs 20–23

Material examined. Australian Capital Territory: 2♀♀, Tidbinbilla , 1 Dec 1935, Mackerras & Fuller ( ZB) . New South Wales: 1♀, Wilson River Reserve , 26 Nov 1966, D. McAlpine ( ZB) ; 1♂, Kembla Heights, American Creek off Cordeaux Rd (34.437°S 150.795°E), 19 Nov 2018, Z. Billingham & G. Theischinger, GHD ( T 21736) . Victoria: 1♂ , Victoria, Bindi, Tambo River at Blackfellows Flat (37.058°S 147.827°E), 29 Nov 2011, Z. Billingham, GHD ( T1522 ) .

Remarks. Skuse (1890) provides the first description of H. (E.) metallica in English, with the original description (Schiner,1868) having been given in German. While the description provided by Skuse is more detailed, the hypopygium was not described in detail. With the availability of fresh material a thorough description of the hypopygium is now possible, along with a description of the ovipositor. A general description of the male is also provided, with particular emphasis on updating the wing venation, the terminology in Skuse (1890) being now somewhat outdated.

Male. body length 11.2 mm, wing length 10.1 mm. Head ( Fig. 20 ) dark greyish brown, vertex with swollen, low, rounded tubercle. Antenna and palpus yellowish brown. Antenna with seven segments, flagellomeres elongate, cylindrical, first segment especially so. Antenna extending back a little past the prescutal pit. Dorsal thoracic segments all dark greyish brown to black, with prominent metallic blueish to greenish sheen. Pleurites greyish brown, metallic sheen less prominent. Coxae, trochanters, femora and tibiae greyish brown, tarsi darkening to black. Wing with deep grey tinge, stigma not evident, veins greyish brown ( Fig. 21 ). Sc long, extending a short distance beyond the fork of Rs, sc-r just before its tip, Rs in close alignment with R 5, the two of similar length, R 2+3 and R 2 each about half the length of the fairly long R 2+3+4, r-m and m-cu in near alignment, both situated a short distance past the base of the discal medial cell, discal medial cell closed, cell m1 lacking. Halter with stem greyish brown, knob pale greyish. Abdomen generally dark greyish brown to black, tergites with prominent metallic blueish to greenish sheen. Hypopygium ( Fig. 22 ) with T9 dark greyish brown with metallic sheen, gonocoxites dark brown with pale, nearly membranous horizontal band at about midlength. Distal margin of tergite with shallow irregular V-shaped concavity, sternite with broad, and considerably deeper V-shaped concavity. Gonocoxites fairly short, subequal to length of T9. Outer gonostylus gently curved, broad at the base and narrowing gradually to a sharply pointed tip. Inner gonostylus broad and fleshy, leaf shaped, a little longer than the outer gonostylus. Interbase greatly developed, branching into two arms, the lower arm broad and trapezoidal in shape, together with the lower arm of the opposing interbase forming a quadrate shield above the aedeagal complex, upper arm with a prominent short, hooked process near its base, then gradually tapering to a blunt tip.Aedeagal complex somewhat low saddle-shaped at base, aedeagus not extending far past the upper arms of the interbase.

Female. Size and colouration much the same as for male. Ovipositor ( Fig. 36 ) with tergite and sternite dark greyish brown, cercus and valve lighter brown. Cercus long, mostly straight, tip rounded. Tip of hypogynial valve reaching to about ½ length of cercus, valve with row of long, thick, setae along dorsal margin.

Discussion. Four species of Hexatoma are known from Australia: H. (E.) aperta Alexander, 1920 and H. (E.) australiensis Alexander, 1920 , both known only from the Cairns area of Queensland, H. (E.) metallica , known from multiple locations from the south of Sydney to the east of Victoria and into the Victorian Alps, and H. (E.) setifera , known only from Uriarra near Canberra. Hexatoma (E.) metallica is the only Australian species whose male is known, with all other species having been described from female specimens; as a result no comparisons can be made between the hypopygia of the Australian species. However, H. (E.) metallica is readily distinguished from all other Australian species of Hexatoma by the body colouration, with no other species showing the prominent metallic sheen on the dorsal surface of thorax and abdomen.

Figures

Figures 20–22. Hexatoma metallica male. (20) head, lateral; (21) wing; (22) hypopygium, dorsal view, with aedeagal complex inset.

Figures 23. Hexatoma metallica female (23) ovipositor, lateral, with hypogynial valve inset.

Figures36–39. Elephantomyia (Elephantomyodes) fumicosta, female.(36) headand rostrum, dorsal; (37) wing; (38) abdominal colouration, dorsal; (39) ovipositor.