Palpada prietorum belongs to a small group of species, the ruficeps subgroup, which has the wing bare or nearly so, but shares some characters with the other member of the vinetorum species group, e.g. ciliate metatibia with apicolateral dens (tooth), and the pilose posterior anepimeron. There are 4 species in this subgroup: bistellata (Hull, 1935), prietorum Mengual spec. nov., ruficeps (Macquart 1842) and suprarufa Thompson, 1999 (see figs. 1–4). Palpada prietorum is most similar to ruficeps but is a smaller and darker species, and can be separated as follows: 1) wing dark on anterobasal 2/3, not hyaline; 2) wing microtrichose in cell R1 in area from fork of RS to end of vein Sc, not bare; 3) tegula and basicosta black, not pale; 4) metacoxa black pilose, not white pilose; 5) mesotibia black pilose, not mostly white pilose; 6) postalar callus black pilose on at least the anterior 3/4, not entirely orange pilose; 7) pleuron black pilose, not mostly or entirely pale pilose; 8) metasternum black pilose, not most white pilose; 9) 2nd and 3rd terga entirely dark pilose, mainly black pilose but more brownish orange anteromedially, not pale yellow pilose on basal 3/4 (2nd) to 2/3 (3rd) (Mengual and Thompson 2008).
Original description from Mengual and Thompson (2008).
MALE.
Head. Face yellow except some individuals dark brown along oral margin, golden pollinose and golden pilose laterally and ventrad of antenna; tubercle distinct, shiny and bare; gena broad, black, silvery white pollinose; lunule golden; frontal triangle golden and black pilose, but mainly golden pilose; vertical triangle as long as eye contiguity, dull brownish pollinose, golden pilose; ocelli reddish; holoptic;
eye golden pilose; antenna orange, black pilose on scape and pedicel; basoflagellomere brownish dorsally in some specimens; arista orange or brownish, bare; occiput silvery pilose and pollinose on ventral 2/3, becoming golden pollinose and pilose on dorsal 1/3.
Thorax. Mostly black, grayish pollinose; postpronotum orange-brownish, orange pilose; scutum completely black, black pollinose, orange-reddish pilose; scutellum intense orange, orange pilose; postalar callus mainly black pilose, with yellow pile on posterior 1/4 to 1/5; pleurae dull grayish-black pollinose, entirely black pilose; dorsal calypter brownish black; ventral calypter light brown; halter pedicel pale; capitulum brownish; spiracular fringes brown; katepimeron black pilose; posterior anepimeron black pilose; dorsomedial anepimeron bare. Wing. Wing hyaline except blackish on anterobasal 2/3; tegula and basicosta black pilose; almost completely bare, microtrichia restricted to narrow vitta along medial area, from posterior to tip of cell C across cell Sc and R1 at level of base of cell R4+5 and across cell R and ending at vein M . Legs. Coxae and trochanters black, black pollinose, black pilose; femora black, shiny except profemur and mesofemur sparsely black pollinose dorsolaterally; tibiae black, black pilose; tarsi brownish yellow to brownish black, orange pilose.
Abdomen. Dorsum mainly black, black-brownish pollinose, except 3rd and 4th terga with medial shiny fascia; 1st tergum whitish-yellow pilose; 2nd tergum usually with 2 yellow-orange lateral maculae but very dark brown in some individuals, orange pilose in the anterior medial 1/2, blackish-brown pilose in the posterior 1/2 and lateral anterior 1/2; 3rd tergum dark brown pilose; rest of posterior terga whitish-yellow pilose; sterna black, black pollinose, white pilose; male genitalia shiny black, white pilose; surstylus with dorsal lobe strongly curved and arcuate, with tip densely microsetose; superior lobe broad, with apicoventral row of microdens and two strong lateral setae.
FEMALE: Unknown.
Palpada (Trichopalpada) prietorum Mengual, 2008.
Mengual, X. & Thompson, F.C. (2008) A taxonomic review of the Palpada ruficeps species group, with the description of a new flower fly from Colombia (Diptera: Syrphidae). Zootaxa 1741, 31-36. [2008.04.04]
Adults were collected hilltopping in the same place on four different occasions (July, 26th and August, 4th of 2004, and of February, 15th and 24th of 2006). On 24 February, they were flying with Palpada cosmia (Schiner, 1868), P. mexicana (Macquart, 1847) and P. ruficeps (Macquart, 1842), where the two former were much more abundant (Mengual and Thompson 2008).
unless otherwise stated