Machimus notatus (Wiedemann)

Dennis, D. Steve, Barnes, Jeffrey K. & Knutson, Lloyd, 2008, Pupal cases of Nearctic robber flies (Diptera: Asilidae), Zootaxa 1868 (1), pp. 1-98 : 86-88

Machimus notatus (Wiedemann)

( Fig. 52 )

The pupal case of Machimus notatus was briefly described by Malloch (1915, 1917) and Bromley (1946) under the name Asilus notatus Wiedemann. The redescription presented here is based on a male pupal case with associated pinned adult from the United States National Museum. It is labeled "Staten Isl., N.Y.; VI, 17, '28; S.W. Bromley Collection 1955."

Redescription: Greatest length, including anterior antennal processes, 16.0 mm; greatest width of thorax 3.8 mm; greatest width of abdomen 3.5 mm, tapering to 1.0 mm at greatest width of abdominal segment 8. Integument subshining light yellow tan, head and thorax slightly darker; bristle­like spines pale yellowish; head processes light reddish brown; anterior antennal processes darker apically, posterior processes more uniformly colored; spines and other processes of abdominal segment 8–9 darker 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; middle and outer posterior processes fused for greater distance, appearing slightly shorter than inner posterior process; outer posterior process apically pointed on inner margin, with flattened, basal, oval area toward dorsum projecting slightly posteriorly beyond process; inner and middle posterior processes apically rounded. Labral sheath small, slightly rugose, especially near posteromedian tubercle. Proboscial sheath laterally rugulose, with median groove posteriorly, slightly ridged on each side, with flattened area of cuticle between groove and small, round, terminal tubercle. Maxillary sheath rugose anteriorly, slightly rugulose posteriorly, with minute tubercle­like swelling on inside margin halfway between sheath tip and posterior margin of labral sheath.

Anterior coxal sheath mostly smooth, with anterior, median, longitudinal split. Prothoracic spiracle elongate­oval, tilted posteriorly on small, smooth, anteriorly ridged callosity, situated midlaterally at anterior margin of thorax. Anterior mesothoracic spines subequal, short, apically acute, situated above base of sheath of mid legs; both spines directed posteriorly; anterior spine more curved on inner margin than posterior spine; posterior spine straight sided, at sharp angle to thoracic surface. Posterior mesothoracic callosity smooth, with apically rounded to acute posterior mesothoracic spine at base of each wing sheath. Wing sheath rugose on posterior half. Thoracic area above wing sheath mostly smooth, except for rugoseness near posterior mesothoracic callosity. Apex of hind leg sheath reaching to middle of abdominal segment 3.

Abdominal spiracles elongate­oval, reddish brown, similar to thoracic spiracles.

Abdominal segment 1 with dorsal transverse row of 10 long, apically recurved spurs, 2 median spines pointing laterally; dorsolateral bristle­like spines absent; with 5 bristle­like spines behind each spiracle; venter obscured by wing and leg sheaths.

Segments 2–6 with dorsomedian transverse row of 6 long, straight spurs alternating with 7 short spines; segment 2 with short, apically blunt spines; segments 3–7 with spines apically rounded, similar to long spurs.

Segments 2–7 with 4–7 (usually 6–7) dorsolateral bristle­like spines and 5–9 (usually 7–9) lateral bristlelike spines behind each spiracle; dorsolateral and lateral bristle­like spines frequently bent at right angle apically.

Segment 2 with 8–11 straight to apically recurved bristle­like spines on each side of, and extending under, hind leg sheath; segments 3–5 with complete transverse row of 27–30 straight to apically recurved ventral bristle­like spines; segments 6 and 7 with 23 and 21 bristle­like spines, respectively.

Segment 8 with 1 dorsal spur on each side of midline, 1–2 dorsolateral spines, small reddish­brown spiracle at lateral midline, 5–6 lateral bristle­like spines on each side, and complete transverse row of 16 overlapping ventral bristle­like spines.

Segment 9 with pair of long dorsal posterolateral processes curved toward each other for entire length; pair of ventral posterolateral processes apically bent at a right angle toward each other, not fused basally to dorsal posterolateral processes; pair of approximate terminal posteroventral tubercles slightly anterior to ventral posterolateral processes, and pair of widely separated midventral tubercles.

Figures

FIGURE 52. Machimus notatus (Wiedemann), abdominal segments 2–6, dorsal view.