Notiphila poliosoma Mathis 1979

Notiphila (Notiphila) poliosoma

DIAGNOSIS.—Specimens of N. poliosoma are among the most distinctive members of the loewi group. Externally, members of this species are generally characterized by extensive gray coloration, by the lacteous, pollinose postfrons, and by the almost entirely pale third antennal segment. The male genitalia are also diagnostic: Ventral process of the epandrium proportionately very long in relation to rest of the epandrium; shape of arms distinctive (Figures 92–94).

DESCRIPTION.—Moderately small to medium-sized shore flies, length 2.96 to 3.76 mm; with gray to slightly brownish gray coloration and very few light brown markings.

Head: Head ratio 1:0.75; postfrons ratio 1:0.70; frons mostly lacteous in coloration, median triangular area and lateral margins slightly lighter. Para-vertical bristle approximately equal to genal bristle, larger than postocellars; at most with 1 fronto-orbital seta. First and second antennal segments mostly dark brown, anterodorsal area of second segment with some pale coloration; third antennal segment mostly pale, yellow, sometimes with some dark tinges along anterodorsal margin; arista with approximately 8 dorsal branches. Pale unicolorous, light yellow; prefrons ratio 1:0.79. Eye ratio 1:0.84; eye-to-cheek ratio 1:0.24. Gena moderately narrow, mostly concolorous with face anteriorly becoming gray posteriorly; genal bristle subequal to paravertical bristle. Maxillary palpus pale, yellow.

Thorax: Mesonotum mostly gray but with some light brown dusted areas, especially posteriorly; scutellum usually lighter gray in coloration than mesonotum. Pleural areas mostly gray, lighter in color than mesonotum; mesopleuron often with a faint light brown maculation area toward dorsal margin. Femora almost entirely gray but with some darker, charcoal areas, apically pale; tibiae and tarsi entirely pale. Setal fascicle of hind basitarsus dark brown to black. Wing ratio 1:0.43; costal vein ratio 1:0.45; M1+2 vein ratio 1:0.81.

Abdomen: Abdomen ratio of males 1:0.67; length of fourth tergum to fifth tergum of males 1:1; fifth tergum ratio of males 1:0.53. Coloration mostly gray, pollinose, third and fourth terga with two small geminate, light brown maculation spots on anterior margin. Male genitalia as in diagnosis and in Figures 92–94.

TYPE-MATERIAL.—Holotype male: “Franklin Co., 16 June 1936, Ohio/A. Peterson, collector/HOLOTYPE Notiphila poliosoma Mathis (red).” Allotype female and three paratypes (1, 2): “Carlinville, Illinois, Charles Robertson Collection (collection numbers 6396 to 6399, INHS).” Other paratypes as follows: 2, 1, Kansas, Linn Co., Marais des Cygnes Wildlife Refuge area, 5 September 1961, D. L. Deonier, on floating leaf of Potomogeton sp. (ISU, WNM); 1, Kansas, Douglas Co., Kansas University Natural History Reserve, 7 June 1963, D. L. Deonier (ISU); 5, 2, Wisconsin, La Crosse Co., 2–3, August 1975, D. F. Sefton (WNM). The holotype will be deposited with the Ohio State University insect collection, Columbus.

ETYMOLOGY.—The epithet poliosoma, of Greek derivation, is a combination of polios (“gray”) plus soma (“body”) in reference to the gray general body coloration.

GEOGRAPHIC DISTRIBUTION.—This species occurs in midwestern United States. Collection dates are from 7 June to 5 September.