Promachus vertebratus (Say)

Dennis, D. Steve, Barnes, Jeffrey K. & Knutson, Lloyd, 2008, Pupal cases of Nearctic robber flies (Diptera: Asilidae), Zootaxa 1868 (1), pp. 1-98 : 67-69

Promachus vertebratus (Say)

( Figs 40–42 )

The following description is based on four male and five female pupal cases from the United States Nation Museum collection. The males are labeled "Crown Point, Ind.; IV­24­34; reared from Lachnosterna ?; Luginbill & Painter Colls," "Dayton, Ind.; VII­27­35; reared from Phyllophaga ?; P. Luginbill and H. R. Painter Colls," "Lafayette, Ind.; VIII­8­39; McCoy field; reared from Phyllophaga ?; P. Luginbill and H. R. Painter Colls," and "Lafayette, Ind., VII­27­39, McCoy field; reared from Phyllophaga ?; P. Luginbill and H. R. Painter Colls." Three females are labeled "Crown Point, Ind.; IV­24­34; reared from Lachnosterna ?; Luginbill & Painter Colls," one female is labeled "Crown Point, Ind.; IX­12­36; reared from Lachnosterna ?; P. Luginbill & H. R. Painter Colls," and one female is labeled "Merrillville, Ind.; VII­29­35; reared from Phyllophaga ?”

The pupal case of P. vertebratus was described by Malloch (1915, 1916, 1917) and Davis (1919). Because these descriptions are incomplete we are redescribing the pupal cases here.

Redescription: Greatest length, including anterior antennal processes, ♂ 21.0–26.0 mm, ♀ 19.0–27.0 mm; greatest width of thorax ♂ 6.0– 6.5 mm, ♀ 6.0– 6.5 mm; greatest width of abdomen ♂ 4.5–5.5 mm, ♀ 5.0–6.0 mm, tapering to ♂ 1.5–2.0 mm and ♀ 1.5–2.5 mm at greatest width of abdominal segment 8. Integument subshining, light golden brown; spines and other processes glistening reddish brown.

Head with pair of dorsally flattened, ventrally wedge­shaped anterior antennal processes not joined at base and group of 3 basally fused posterior antennal processes located ventrolaterally on each side; middle and outer posterior processes closer together and fused basally for greater distance, appearing shorter than inner process; middle and outer posterior processes rounded apically; inner posterior process more acute apically, especially on posterior margin. Labral sheath rugose, with apical keel. Proboscial sheath rugose, with 2 tubercles on each side and large, basally concave median tubercle posteriorly; innermost tubercle smaller than outer tubercle and somewhat hidden in rugoseness. Maxillary sheath with large, apically rounded posterior process, rugose about process and often along innermost margin, especially on margin next to labral sheath.

Anterior coxal sheath irregularly rugulose, with anterior, median, longitudinal split; with 1–2 small rugulose callosities on each side of proboscial sheath. Prothoracic spiracle on very rugose area, situated midlaterally at anterior margin of thorax. Anterior mesothoracic spines consisting of pair of dorsoventrally flattened, subequal spines on each side of thorax above mid leg sheaths; anterior spine broader basally than posterior spine, curved posteriorly and acute along posterior margin; posterior spine straight and medially acute, sometimes more wedge­shaped ventrally; thoracic area above spines rugose. Posterior mesothoracic callosity large, slightly rugose, with sclerotized margin, situated at base of each wing sheath; posterior mesothoracic spine short, apically rounded, located medially on posterior margin of callosity. Wing sheath with posterior half rugose; large, apically rounded, spine­like tubercle near base; 2 small median tubercles posteriorly; and small, circular, upraised area posterior to median tubercles and more toward outer edge of wing sheath. Thoracic area above wing sheath irregularly rugose. Apex of hind leg sheath reaching between middle and posterior margin of abdominal segment 3.

Abdominal spiracles C­shaped, shining reddish brown, situated along midline laterally.

Abdominal segment 1 with dorsal transverse row of 12–13 (usually 12) apically recurved spurs along anterior margin; outermost spur and sometimes second spur on each side of midline shorter than other subequal spurs; dorsolateral bristle­like spurs absent; 3 lateral bristle­like spines behind spiracle; venter obscured by wing and leg sheaths.

Segments 2–6 with dorsomedian transverse row of 11–14 alternating broad, long, straight to apically recurved spurs and narrow, short, straight spines pointing posteriorly; spines slightly in front of long spurs; some short spines bifurcate or irregularly furcate.

Segment 7 with dorsomedian transverse row of 6 long, sagittate, straight to apically recurved spurs; rarely with small spine between large spurs.

Segments 2–7 with 5–9 dorsolateral bristle­like spines of unequal size, often basally fused; segments 2–6 and segment 7 with 8–10 and 6–7 narrow, mostly long bristle­like spines behind each spiracle, respectively; outermost spine on each side and sometimes other spines one­third to three­fourths as long as most spines; rarely with some spines bifurcate.

Segment 2 with 4–7 long, median, ventral bristle­like spines on each side of hind leg sheath. Segments 3– 7 with ventral transverse row of 16–21 median bristle­like spines in male, with 20–24 ventral spines in female; some cases with median space on segment 3 or with bristle­like spines missing where hind leg sheath presumably rubbed against venter; median pair of spines on some segments darker and slightly in front of surrounding spines or slightly fused basally and diverging apically; some spines bifurcate and/or smaller than others.

Segments 8–9 frequently bent ventrally at 45–90 0 angle so that ventral bristle­like spines on segment 7 touch venter of segment 8. Segment 8 with 2 dorsal spurs on each side of midline, outermost spur usually shorter than innermost spur; spiracle not visible; with 3–4 lateral bristle­like spines on each side; males with 2 long, median, diverging ventral spines and 2 short ventrolateral spines; females lacking ventral spines.

Segment 9 with pair of long dorsal posterolateral processes pointed dorsally and pair of small ventral posterolateral processes fused basally to dorsal posterolateral processes; with 2 terminal ventromedian tubercles just anterior to ventral posterolateral processes and 2 midventral tubercles shorter and closer together in females.

Figures

FIGURES 40–42. Promachus vertebratus (Say), 40. ventral view with enlarged view of facial area. 41. lateral view, 42. dorsal view. Abbreviations: acsh = anterior coxal sheath, prsh = proboscial sheath.