Diario del proyecto Bombyliidae (Bee Flies) - Southern Africa

Systropus (Systropus) macilentus Wiedemann 1820

An elegant Ammophila wasp-like Bombyliid of reddish to reddish-brown and black colour pattern (first abdominal segment, abdominal segments II-V above are reddish) with infuscate wings with 2 submarginal cells.
Best identified by comparing to photo of type.
https://www.gbif.org/occurrence/3458602669#occurrencePage_media

Original description (page 19) with figure in:
Wiedemann, C.R.W. 1820. Munus rectoris in Academia Christiano-Albertina iterum aditurus nova dipterorum genera. Offert iconibusque illustrat. C. F. Mohr, Kiliae Holsatorum
https://ia801606.us.archive.org/29/items/novadipterorumg00wiedgoog/novadipterorumg00wiedgoog.pdf

Systropus macilentus group
A group of 4 species characterized as follows:

• fore and mid tibiae without conspicuous silvery pubescence,
• hind femora with some spines below;
• pteropleuron without a distinctly tufted patch of silvery or white hair on posterior margin;
• petiole of four segments (II-V), club well differentiated although small;
• pale areas of body and legs reddish, reddish brown or brown;
• wing distinctly infuscate, with 2 or 3 submarginal cells.
• restricted to the Cape and adjacent south-west areas

Detailled redescritption of S. macilentus (and key) in:
Bowden, J. 1967. Studies in African Bombyliidae. VI. A provisional classification of the Ethiopian Systropinae with descriptions of new and little known species, Journal of the Entomological Society of Southern Africa 30, No. 2
https://journals.co.za/doi/pdf/10.10520/AJA00128789_2611

Type locality: Cape of Good Hope, Western Cape, South Africa

iNat observations:
https://www.inaturalist.org/observations/242830988
https://www.inaturalist.org/observations/241693697

This fairly large and striking Australoechus species is easily recognisable by the long dense, and shaggy white and black pubescence and well-developed bristles on the body and the dimidiate wings, in which the anterior half is brown and without any distinct spots in posterior hyaline part or with only a feeble infuscation at base of fourth posterior cell. Pubescence discally on thorax with numerous dark or brownish hairs, not distinctly striped. Spines of the legs black.

Original description in:
Macquart, P.J.M. 1840. Diptères exotiques nouveauxou peu connus. Tome deuxieme. 1er partie. Roret, Paris.
https://www.biodiversitylibrary.org/item/54217#page/94/mode/1up

Redescription in Hesse 1928:
https://www.biodiversitylibrary.org/page/40845178#page/253/mode/1up

Distribution: Western Cape and Eastern Cape, South Africa

iNat observations:
https://www.inaturalist.org/observations/244753259
https://www.inaturalist.org/observations/244752771
https://www.inaturalist.org/observations/244550128