Promachus fitchii Osten Sacken, 1878

Dennis, D. Steve, Barnes, Jeffrey K. & Knutson, Lloyd, 2008, Pupal cases of Nearctic robber flies (Diptera: Asilidae), Zootaxa 1868 (1), pp. 1-98 : 64-66

Promachus fitchii Osten Sacken

( Fig. 39 )

The pupal case of Promachus fitchii was described previously by Malloch (1916, 1917), Davis (1919), and Bromley (1946). A more complete description is presented here based on two cases with pinned adult males from the United States National Museum. These specimens are labeled "W. Springfield No. 915368; 18 VII 16," and "Madison, Wisc.; VI­12­17; Lafayette, Cage No. D252a; J.J. Davis Collector; Collection J.M. Aldrich."

Redescription: Greatest length, including anterior antennal processes, 19.0– 24.5 mm; greatest width of thorax 5.0–6.0 mm; greatest width of abdomen 4.5–5.5 mm, tapering to 2.5–3.0 mm at greatest width of abdominal segment 8. Integument subshining light yellow to golden brown; spines and other processes glistening reddish brown, darker apically; spurs uniformly reddish brown.

Head with pair of dorsally flattened, ventrally slightly 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 fused for greater distance, closer together, appearing shorter than inner process; middle and outer posterior processes rounded apically, inner or first posterior process more acute; outer or third posterior process slightly elbowed basally. Labral sheath rugose and with large keel posteriorly; keel with inverted V­shaped sclerotized ridge apically. Proboscial sheath rugose on each side of midline, with 2 subequal tubercles on each side and large, basally concave tubercle posteriorly; innermost tubercle sometimes concave apically. Maxillary sheath mostly smooth, with large, apically rounded, rugose process posteriorly; with small tubercles lateral to labral sheath.

Anterior coxal sheath mostly smooth or with slightly rugulose areas on margins, with anterior median, longitudinal split and small callosity on each side of midline just posterior to large proboscial sheath tubercle. Prothoracic spiracle on flush rugose area, situated midlaterally at anterior margin of thorax. Anterior mesothoracic spines consisting of pair of dorsoventrally flattened, subequal, apically curved spines on each side of thorax above bases of sheaths of mid legs; anterior spine broader basally and usually curved posteriorly; posterior spine straighter. Posterior mesothoracic callosity large, slightly rugose, with apically rounded posterior mesothoracic spine of variable length located medially on posterior margin. Wing sheath irregularly rugulose, with large, apically rounded tubercle near base and 2 minute median tubercles posteriorly. Thoracic area above wing sheath mostly smooth. Apex of hind leg sheath reaching between posterior margin of abdominal segment 2 and middle of abdominal segment 3.

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

Abdominal segment 1 with dorsal transverse row of 12–14 apically recurved spurs; most spurs subequal, with outermost spine on each side and 2 median spines one­third to one­half as long as others; dorsolateral bristle­like spines absent; with 2–3 (usually 3) bristle­like spines behind spiracle; venter obscured by wing and leg sheaths.

Segments 2–6 with dorsomedian transverse row of 11–14 alternating long, narrow, sagittate, straight to apically recurved spurs and short, broad, straight, bifurcate or multifurcate spines mostly in even row with large spurs; with 3–5 long dorsolateral bristle­like spines.

Segment 7 with dorsomedian transverse row of 10 alternating long, narrow spurs and short spines and 3–4 dorsolateral bristle­like spines.

Segments 2–7 with 5–8 long, straight to curved bristle­like spines behind each spiracle; outermost spine on each side sometimes shorter than other spines; spines rarely bifurcate.

Segment 2 with 4–6 long, median, ventral bristle­like spines on each side of hind leg sheath; some inner spines shorter than others, presumably due to leg sheaths rubbing. Segments 3–6 with 14–20 long, median, ventral bristle­like spines in complete transverse row. Segment 7 with 11–14 ventral bristle­like spines; spines on segments 3–5 curved and bent; spines on segments 6–7 straight to apically recurved; some spines bifurcate or shorter than others.

Segment 8 with 1–2 dorsal spurs on each side of midline; small spiracle at lateral midline; lacking dorsolateral bristle­like spines; with 4–5 lateral bristle­like spines, usually in pairs on callosity, and 4 subequal median ventral bristle­like spines on large callosity.

Segment 9 elongate, with pair of long, basally broad dorsal posterolateral processes and pair of small ventral posterolateral processes not fused basally to dorsal posterolateral processes; with 2 terminal median ventral tubercles just anterior to ventral posterolateral processes, small midventral tubercle, and pair of large tubercles anterior to ventromedian tubercles; venter rugose posteriorly.

Figures

FIGURE 39. Promachus fitchii Osten Sacken, abdominal segments 2–4, anterodorsal view.