Pachyrrhiza parargentata, Irwin & Winterton, 2021

Irwin, Michael E. & Winterton, Shaun L., 2021, Revision of the Patagonian stiletto fly genus Pachyrrhiza Philippi (Therevidae Agapophytinae), Zootaxa 4975 (2), pp. 273-305 : 287-290

publication ID 10.11646/zootaxa.4975.2.3

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scientific name

Pachyrrhiza parargentata

sp. nov.

Pachyrrhiza parargentata View in CoL sp. n.

( Figs 18–21 View FIGURE 18 View FIGURE 19 View FIGURE 20 View FIGURE 21 , 30H View FIGURE 30 , 31C View FIGURE 31 , 34A View FIGURE 34 , 35 View FIGURE 35 )


Diagnosis. Parafacial with patch of black setae adjacent to gena; hind femur with one or two subapical anteroventral macrosetae; prosternum without setae medially; wing mostly hyaline, slightly mottled infuscate anteriorly; male abdomen with silver velutum pubescence; mid and hind coxae with white setae on posterior surfaces.

Description. Body length: 6.5–7.5 mm. Head with frons light brown pubescent, female with dark brown band above antenna, frontal vestiture with patch of short setae above antenna, shorter than setae on scape, female with short to moderate length setae over entire frons; parafacial setae as small dark patch adjacent to gena; genal setae white; occiput brown with grey pubescence, denser laterally; antennal scape slightly longer than maximum width, brown with grey pubescence, densely covered with large, dark setae (fewer in female); flagellum brown with grey pubescence. Thorax with scutum and scutellum with grey-tan pubescence and scattered, dark brown markings, numerous erect elongate black setae, denser and longer anteriorly, especially in male, setal bases dark brown; scutal markings as narrow brown medial stripe, lateral stripes broken; pleuron with dense silver-grey pubescence; prosternum without setae medially; katatergite setae all white; femora dark brown (male) or dark yellow, suffused with brown-black dorsally (female), short dark setae, admixed with elongate pale setae ventrally; hind femur with one or two subapical anteroventral macrosetae; tibiae yellow, dark grey-brown apically; tarsi dark yellow with apices brown; wing hyaline, mottled infuscate anteriorly, costal cell brown infuscate basally, yellow distally; scutal chaetotaxy: notopleural, 3–5; supra alar, 1; post alar, 1; dorsocentral, 4; scutellar, 2. Abdomen base colour mostly dark brown in male, female brown with glaucous grey pubescence, intersegmental membrane distinctly pale; male vestiture with extensive long, pale setae, female with scattered, short, dark setae, male abdomen with silver velutum on tergites 2–7; terminalia dark yellow. Male and female genitalia as per genus description except epandrium with dark medial stripe and distiphallus narrow distally.

Etymology. The specific epithet is modified after P. argentata with the Greek prefix para-, beside; referring to the similarity of the two species.

Comments. Pachyrrhiza parargentata sp. n. is known from relatively few specimens and appears endemic to the Las Trancas Valley. It is very similar to P. argentatoides sp. n. but is differentiated by the presence of pale setae on the posterior surfaces of the mid and hind coxae.

Type material. Holotype male, CHILE: Ñuble Province : Las Trancas [approximated as -36.908, -71.492], 1200m, Malaise, 24–27.XI.1994, L. Peña-Ugarte ( MEI117062 ; MEUC) GoogleMaps . Paratypes. CHILE: Ñuble Province: 1 female, same data as holotype ( MEI117067 ; MEUC) GoogleMaps ; 1 male, 3 km E. Las Trancas (-36.915, -71.453), 4.I.2000, M.E. Irwin, hand netted ( MEI121268 ; CSCA) GoogleMaps ; 1 male, Las Trancas , 73 km SE Chilián [approximated as -36.908, -71.492], 14–15.XII.1993, G.&M. Wood ( MEI123789 ; CAS) GoogleMaps ; 1 male, 1 female, Las Trancas [approximated as - 36.908, -71.492], 21–30.XI.1964, L.E. Peña ( MEI079709 , 079768 ; CNC) GoogleMaps .


Universidad de Chile


California State Collection of Arthropods


California Academy of Sciences


Canadian National Collection of Insects, Arachnids, and Nematodes













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