Thraxan, Yeates & Lambkin, 1998

Li, Xuankun, Yuan, David, Rodriguez, Juanita & Yeates, David K., 2019, Sand wasp (Hymenoptera: Crabronidae) parasites emerging from mud wasp nests (Hymenoptera: Sphecidae) - a reliable host record of Thraxan Yeates & Lambkin (Diptera: Bombyliidae: Anthracinae) with description of the pupal exuviae of three Thraxan species, Zootaxa 4609 (1), pp. 149-159 : 150-152

Thraxan sp.

( Fig. 1 )

Specimens examined. Australia, ACT, ♀ Pupal exuvia, Black Mountain, Bike tunnel, 5 September 2018 ; Pupated 30 September ; Emerged 22 October . ♀ Pupal exuvia, Australian National University campus, 1 October ; Pupated 8 October ; Emerged 4 November .

Description. Pupal exuvia. Length: 13.0 mm. Head width: 2.2 mm. Thorax width: 2.9 mm. Abdominal width: 3.0 mm, tapering to 0.9 mm at width of anal segment. Coloration. Predominantly pale yellow, spines dark brown to black. Head. Armed with 3 pairs of cephalic spines. One anterior antennal process (aap) present, base area with one dorsal long hair and one lateral long hair ( Figs 1g, h ). Two posterior antennal processes (pap) present, two pap slightly shorter than aap ( Figs 1g, h ). One median facial hair (mfha) present, one frontal spine (fsp) present. Labral sheath (lsh) with a small ventral subapical process. Proboscidal sheath (prsh) short, about 0.5 length of lsh, slightly rugose laterally. Maxillary sheath (msh) smooth, extending and connecting well after prsh. Palpal sheath (pash) rugose, extending slightly over lsh ( Figs 1c, d ). One posterolateral facial hair (plfha) present. Thorax. Mostly smooth, one small posterior mesothoracic callosity (pmc) present. Thorax with one long hair located anterior of pmc, one long hair located above pmc, and two pairs of dorsal hairs. Wing sheath (wsh) and base half of leg sheaths (lesh) smooth, apex half of lesh rugose ( Fig. 1d ). Wsh reaching abdominal segment 3. Fore leg sheath (lesh 1) not exceeding apex of wing sheath, mid leg heath (lesh 2) reaching abdominal segment 3, hind leg sheath (lesh 3) reaching abdominal segment 4. Abdomen. Eight abdominal segments visible, segments 8 and 9 fused ( Fig. 1b ). Abdominal tergite 1 with a row of dense long hairs. Abdominal tergites 2 to 6 with well-developed chitinous rods with both apexes raised as spines on tergites 2 to 5, and posterior apex raised as spines on tergite 6, and with short spines on tergite 7; long hairs present laterally and between two chitinous rods or spines on tergites 2 to 7 ( Fig. 1e ). Tergite 8+9 with one dorsal spine, and one posterolateral callosity. Abdominal pleuras 2 to 7 each with a cambered row of long hairs, pleura 8+9 with two long hairs. Sternites 2 to 7 and 8+9 with a transverse row of hairs on posterior half. Anal segment smooth, some ventral small callosities present ( Fig. 1j ). Dorsal posterolateral process (dpp) small and fused, ventral posterolateral process (vpp) elongate, acute with one inboard spine, dorsal area with one dorsal spine and one ventral spine ( Figs 1i, j ).

Host. Pison simillimum Smith ( Hymenoptera : Crabronidae : Crabroninae ).

Figures

FIGURE 1 Thraxan sp. Female Pupal exuvia: (a) dorsal; (b) lateral; (c) head, ventral; (d); head and thorax, ventral; (e) abdominal segments 2 to 4, dorsal; (f) cephalic spines, dorsal; (g) cephalic spines, frontal; (h) cephalic spines, lateral; (i) anal segment, dorsal; (j) anal segment, ventral. Scale bars = 1 mm (c, e–j); = 0.1 mm (a, b, d). Abbreviations: aap = anterior antennal process; absr = abdominal spiracle; dpp = dorsal posterolateral process; fsp = frontal spine; lesh 1 = fore leg sheath; lesh 2 = mid leg sheath; lesh 3 = hind leg sheath; lfsp = lateral facial spine; lsh = labral sheath; mfha = median facial hair; msh = maxillary sheath; pap = posterior antennal process; pash = palpal sheath; plfha = posterolateral facial hair; pmc = posterior mesothoracic callosity; prsh = proboscidal sheath; vpp = ventral posterolateral process; wsh = wing sheath.