Plyomydas peruviensis, J. Wilcox & N. Papavero, 1971

J. Wilcox & N. Papavero, 1971, The American Genera of Mydidae (Diptera), with the Description of three new Genera and two new Species, Arquivos de Zoologia 21 (2), pp. 41-119 : 108-112

Plyomydas peruviensis , sp. n.

( Fig. 128 )

Male: Length 12 mm.

Head black, gibbosity brown; broad sides of face, frons, a small spot above at middle of gibbosity, and the occiput densely white pollinose. Hairs yellowish, sparse, semi-erect on gibbosity, long and dense to sides of antennae, quite long and erect on frons, upper occiput and below proboscis; short, erect, whitish hairs on lower occiput. Proboscis brown. Face at lower eye margin 15, at antennae 25, at vertex 17, and one eye 17, in width. Antennae black, apical two-thirds of club reddish: hairs below on segments 1-2 short yellowish, above black; segments 12-5-35-40 (16) in length (width) (Fig. 33).

Mesonotum dull black, humeri, lateral margins and postalar calli brown. Humeri, lateral margins, and dorsocentral stripes extending to Genus Pseudonomoneura M.

Bequaert

Psettdonomoneura M. Bequaert, 1961: 13. Type-species, Lepiomydas hirtus Coquillett (orig. des.).

Head in anterior view about one and one-half times as broad as high; face at antennae about five-thirteenths width of head; oral margin at about three-fifths distance from lower eye margin to antennae. Stem of proboscis usually slender, labella attached at apex, length including labella ranges from about one-half length (obsolete) to two and one-half times length of oral cavity; palpi short and about two times as long as wide. Antennal segment 1 cylindrical, one and one-half to two times as long as wide; 2 one-third to one-half as long as 1, and about one and one-half times as broad as long; 3 usually two to three times as long as 1-2, in species with obsolete proboscis it may be slender or stout and subequal in length to 1-2; club usually shorter than segment 3 and widest at three-fourths its length, in species with obsolete proboscis it is usually longer than 3 (Figs. 38-41).

Mesonotum with dense, semi-erect hairs on lateral and posterior margins and in dorsocentral rows and without pollen, varying to species with sparse pile and dense pollen on these areas. Scutellum and arms bare. Postscutellum smooth, lateral slopes bare, varying to species with dense clumps of long hairs, and varying from densely pollinose to bare of pollen. Pleura with dense clump of hairs on episternum-1, pteropleura, laterotergite, and metasternum; katepimeron long pilose in a few species; in a few females these hairs and also those on the postscutellum are very short and' sparse.

Abdominal tergite-1a slightly rounded, usually long pilose but with very short hairs in some females, pollinose in some species but usually without pollen; 1p similar; tergite 2 and at times 3 with long hairs basally, apical one-half or less of 3-6 or 3-7 with dense recumbent hairs in some males, sparse and recumbent in other males; bullae (Fig. 56) oval, two to three times as long as broad, minute in some females. Some females have dense, long hairs on tergite 1 and base of 2 but usually they are long and sparse and recumbent on 2-6; 7-8 with many retrorse hairs. Male sternites 2-7 with many short, recumbent hairs, 8 one-fifth length of 7 and usually with long hairs. Female sternites 2-6 with short recumbent hairs, 7-8 with retrorse hairs; apex with circlets of strong spines. Male genitalia (Figs. 129-131): hypandrium completely coalescent with basistyli, the resulting structure remarkably elongate and subrectangular; apical processes of gonopods reduced, short, ventrally bent; aedeagus with a thick ventral bulb, the neck ventrally bent (a unique character among American Mydidae ); epandrial halves united at base, very well-developed, bowl-shaped, with an apical prolongation also ventrally bent; cerci fused at base forming with anal lamellae an erect tube arising from middle of epandrial halves.

Fore and middle femora slightly swollen, about one and one-half times as wide as their tibiae. Hind femora slightly swollen, six or seven times as long as broad; about 12 sharp, slightly tuberculate spines on venter; hairs short, recumbent to long erect. Hind tibiae cylindrical with three or more apical bristles. Hind metatarsus about three times as long as wide and subequal in length to 2-3.

Alulae with a fringe of short, sparse, fine hairs. Wings about three and one-third times as long as wide; second submarginal cell closed, stump vein R 3 near base absent or short; first posterior cell open or closed; posterior crossvein absent; ambient vein weak; axillary lobe one and one-half to two times as long as broad.

Length: 9-20 mm.

Geographic range: U. S. A. (Arizona, California, Nevada, Utah), Mexico (Baja California, Coahuila).

Figures

Fig. 128, Plyomydas peruviensis, gen. n., Spa n., whole insect (note: head upside down).