Ceraturgus fasciatus Walker

Dennis, D. Steve, Barnes, Jeffrey K. & Knutson, Lloyd, 2008, Pupal cases of Nearctic robber flies (Diptera: Asilidae), Zootaxa 1868 (1), pp. 1-98: 36-37

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http://doi.org/ 10.11646/zootaxa.1868.1.1



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Ceraturgus fasciatus Walker


Ceraturgus fasciatus Walker  

( Fig. 16)

Malloch (1917) figured and described the pupal case of Ceraturgus fasciatus   (as C. cruciatus (Say))   from specimens collected at Wolfville, Maryland (? = Wolfsville, Frederick County, Maryland). An adult emerged from one of his specimens, allowing for species identification. Bromley (1946) republished Malloch’s figure, but he did not describe the pupal case. The following description is based on a single case from the Illinois Natural History Survey that is labeled "Asilid pupa; Wolfville, Md.; My 14, 14; Ceraturgus cruciatus   .” This is apparently one of the pupal cases that Malloch (1917) described. The specimen, which is preserved in alcohol, is severely wrinkled and in generally poor condition. It bears well developed ventral tubercles on abdominal segment 9 and is therefore probably a male.

Osten Sacken (1878) synonymized the eastern C. fasciatus   with the midwestern C. cruciatus   , and this synonymy was repeated by all subsequent authors. It is now clear that the 2 species are distinct ( Barnes 2008). Ceraturgus fasciatus   ranges from Ontario and New England south to North Carolina and west to Michigan and Mississippi. It is the most common North American species in a small genus of rare species. Ceraturgus cruciatus   ranges from Wisconsin south to Arkansas and west to the Dakotas and Oklahoma.

Redescription: Greatest length, including anterior antennal processes, 16.6 mm; greatest width of thorax 5.5 mm; greatest width of abdomen 5.1 mm, tapering to 3.0 mm at greatest width of abdominal segment 8. Integument subshining, pale 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 6 apically round to acute, basally fused posterior antennal processes shorter than anterior antennal processes, located ventrolaterally on each side, reaching to anterior mesothoracic spines. Labral sheath swollen and smooth, lacking distinct keel. Palpal sheath small, distinct, pointing diagonally inward near apex of labral sheath. Proboscial sheath smooth, with small posterior tubercle. Maxillary sheath smooth to slightly rugulose, extending down half length of proboscial sheath.

Anterior coxal sheath smooth to irregularly rugulose, with anterior, median, longitudinal split. Prothoracic spiracle oval, distinctly raised, dark brown, situated midlaterally at anterior margin of thorax. First anterior mesothoracic spine vestigial, represented by small, rounded tubercle; second anterior mesothoracic spine dark brown, stout, acuminate, situated between mid leg sheath and wing sheath. Posterior mesothoracic callosity rugose, carinate, lacking posterior mesothoracic spine. Wing sheath smooth, lacking distinct tubercles. Apex of hind leg sheath reaching posterior margin of abdominal segment 3.

Abdominal spiracles reniform, distinctly raised above surface of integument, light yellowish brown on outer surface, darker around perimeter.

Abdominal segment 1 with dorsal transverse row of 13 spatulate, sometimes bifurcate, apically recurved spurs and vertical row of 2–3 lateral bristle­like spines behind spiracle; venter obscured by wing and leg sheaths.

Segments 2–3 with dorsal transverse row of 13–15 alternating short, truncate, sometimes bifurcate spines and long, spatulate to acuminate spurs. Segments 4–6 with dorsal transverse row of 12–13 alternating short, acuminate spines and longer, acuminate spurs. Segment 7 with dorsal transverse row of 9 alternating short, acuminate spines and longer, acuminate spurs.

Segments 2–3 lacking dorsolateral bristle­like spines. Segments 4–7 with 4–5 thin, acuminate dorsolateral bristle­like spines lateral to dorsal transverse row.

Segments 2–7 with 4–5 acuminate, lateral bristle­like spines behind each spiracle.

Segments 1–4 lacking ventral bristle­like spines; segment 5 with row of 4 short, ventral bristle­like spines; segment 6 with row of 12 longer, ventral bristle­like spines divided by wide median space; segment 7 with row of 17 still longer ventral bristle­like spines divided by wide median space.

Segment 8 with row of 4 long, dorsal spurs or spines of unequal length on each side of midline, 8–9 long, lateral bristle­like spines, and about 12 ventral bristle­like spines; spiracle not visible.

Segment 9 with pair of long, straight, spine­like dorsal posterolateral processes and pair of shorter, straight, spine­like ventral posterolateral processes; ventromedian tubercles diverging posteriorly.