Gonomyia (Paralipophleps) wirthiana Alexander 1970

Gonomyia (Paralipophleps) wirthiana

General coloration of body and wings as in the subgenus, thoracic pleura conspicuously striped longitudinally with dark brown and white; male hypopygium with outer apical angle of basistyle produced into a flattened blade, with a fleshy lobe at its base; dististyle a broadly flattened pale plate, apex nearly truncate, with a blackened bidentate area; phallosome with 2 pairs of elongate rods, tips of one pair acute, of the other obtuse.

MALE.—Length about 5.5–6 mm; wing 3.5–4 mm.

FEMALE.—Length about 5.5–6 mm; wing 4–4.2 mm.

Rostrum and palpi black. Antennae with scape, pedicel, and proximal 2 flagellar segments orange yellow, remainder dark brown to black; outer flagellar segments long-cylindrical, verticils of the 3rd and succeeding 5 or 6 segments exceedingly long, about one-third the entire flagellum, of the outer segments shorter but still longer than the segments. Head very pale yellow, center of vertex weakly darkened.

Pronotum china white, including also the pretergites and narrow lateral praescutal margins, the latter extended posteriorly across the wing base to include the dorsal pleurotergite and lateral parts of the mediotergite. Mesonotal praescutum light chestnut brown, patterned with slightly darker brown, including a central stripe and narrower sublateral lines adjoining the whitened margins; scutum with lobes chestnut brown, lateral mesal borders dark brown, central region yellow with a vague central darkening; scutellum yellow, very narrowly bordered posteriorly by dark brown, variegated as indicated above. Pleura with the ground dark brown, appearing as 2 narrow longitudinal stripes that enclose a slightly broader china white ventral line; more dorsally below the wing root with a slightly separated brown line that includes the propleura, the 2 darkened stripes enclosing a slightly paler brownish yellow line. Halteres yellow, base of stem infuscated, apex of knob yellowed. Legs with coxae whitened, apex of fore pair and base of middle dark brown, being included in the ventral dark brown pleural stripe; trochanters yellow; femora yellow, with a narrow subterminal brown ring, the narrow tip pale; tibiae and tarsi brown. Wings (Figure 47) light brown, prearcular and costal fields clear light yellow, more expanded surrounding the dark brown stigma, including all of cell R1 and along vein C virtually to wing tip; very narrow and vague darkenings over cord and outer end of cell 1st M2, best indicated by a darkening of the veins; remaining veins yellowed, trichia black, very short and relatively sparse, including vein R5, all outer medial branches and outer end of Cu1. Venation: Sc1 ending just before origin of Rs, anterior branch of the latter strongly upcurved, very pale and difficult to see against the ground; veins R5 and M1+2 convergent outwardly, strongly narrowing cell R5; m-cu close to fork of M.

Abdominal tergites obscure yellow, posterior borders narrowly brownish black, median area with a much paler brown longitudinal line; sternites yellowed medially, light brown on sides and along posterior border; 9th tergite light yellow, remainder of hypopygium slightly darker yellow. Male hypopygium (Figure 59) with outer lateral angle of basistyle, b, produced into a flattened blade that terminates in an acute spine, at its base with an additional nearly apical fleshy lobe with very long setae. Dististyle, d, a broadly flattened pale plate, apex very obtuse to nearly truncate, bearing a slightly bidentate blackened area, the 2 modified setae at outer edge of this area. Phallosome, p, including 2 long acute spines and 2 longer narrow pale rods, their tips obtuse; ventral plate terminating in 2 small divergent arms.

Holotype, male, Clarke Hall, Dominica, 1–10 February 1965 (Wirth). Allotopotype, female, 21–28 February 1965 (Wirth). Paratopotypes, numerous males and females, 8 January-20 March 1965 (Wirth), 13–17 October 1966 (Gumey). Paratypes, males, Antrim, 304.8 m (1,000 ft), 11–20 March 1956 (Clarke).

I take unusual pleasure in naming this distinct fly for Dr. Willis W. Wirth, distinguished student of the Diptera, to whom much of our knowledge of Dominican flies is due. The species is readily told from other regional members of the subgenus by the conformation of the dististyle of the hypopygium.

Eriopterodes, new genus

Antennae short; pedicel enlarged-oval, proximal 2 flagellar segments short and crowded, closely approximated to partially fused, the suture indicated; succeeding segments progressively more elongate outwardly, with very long verticils, the longest exceeding twice the length of the segments; outer 3 segments very long, without verticils, the preceding one with a single such seta. Legs with trochanters, femora, tibiae, and proximal ends of basitarsi with abundant to dense elongate scales, outer segments with normal setae; claws very small. Wings (Figure 63) in the genotype, celestis, with trichia of veins unusually stout, from microscopic punctures, tips obtuse, in laetipleura the scales long and of normal thickness. Venation: Cord at near midlength of wing; cell M2 open by atrophy of m; m-cu at or beyond fork of M; vein 2nd A only slightly sinuous, terminating opposite or before m-cu. Male hypopygium not inverted, the tergite dorsal in position, its median area produced into a broad lobe. Basistyle without lobes or modifications. Dististyles 2, terminal, both simple, long and slender; outer style nearly straight, at apex with 2 divergent teeth; inner style virtually as long, curved gently to the obtuse tip. Phallosome unusually simple, including the long slender aedeagus, its base broader, outwardly narrowed to the acute tip; gonapophysis simple, pale, bladelike, tip obtuse, base dilated.

GENOTYPE.—Erioptera (Erioptera) celestis (Alexander), 1940, page 294. Ecuador and Venezuela. I consider the materials in the present series from Dominica to represent an undescribed subspecies, Eriopterodes celestis dominicana, new subspecies. The Mexican E. laetipleura (Alexander) with unpatterned wings, likewise belongs here.

The hypopygial feature of a simple aedeagus separates the present group from Erioptera Meigen and its various subgenera, which have the apex of the aedeagus bifurcate. Certain other groups earlier associated with Erioptera, such as Arctoconopa Alexander, now are believed to represent entirely distinct genera. The long slender aedeagus of Eriopterodes is suggestive of the condition found in the genus Molophilus Curtis, particularly in the subgenus Promolophilus Alexander, where the structure is unusually short but stout.