Notiphila pallicornis Mathis 1979

Notiphila (Notiphila) pallicornis

DIAGNOSIS.—In most respects, specimens of N. pallicornis are similar to members of the adusta group but they also resemble taxa of the avia group. Of the species of the adusta group, they are similar to specimens of N. adusta, N. biseriata, and N. footei. Like N. pallicornis, specimens of these species have an enlarged hypandrial process that is apically covered with spinules. The general shape of the process varies, however, from species to species. In N. pallicornis, the process is more slender and not as heavily clothed with spinules. The conformation of the ventral epandrial process is also similar to that of N. adusta but differs in having the apices of the arms turned inward. The shape of the basiphallus of specimens of N. pallicornis is similar to that found in members of the avia group, being much longer than wide. See Figures 32–33. Externally, the entirely pale antennal segments are diagnostic.

DESCRIPTION.—Medium-sized shore flies as based on the length of the thorax; with grayish tan background coloration and a general absence of darker markings.

Head: Head ratio 1:0.71; postfrons ratio 1:0.55, frons generally unicolorous but with darker appearing broad stripes toward lateral margin of mesofrons when viewed from some angles; paravertical bristle only slightly larger than postocellar setae, much smaller than genal bristle; at most with 1 pair of small proclinate, fronto-orbital setae. Antennal segments entirely pale, bright yellow; arista with approximately 8–9 dorsal branches. Face nearly concolorous with frons, yellow but not appearing velvety from some angles; facial setae not strongly developed, mostly hairlike; prefrons ratio 1:0.63. Eye ratio 1:0.75; eye-to-cheek ratio 1:0.26. Gena moderately wide, concolorous with face anteriorly, becoming grayer posteriorly; genal bristle prominent, larger than paravertical bristle. Maxillary palpus pale, bright yellow.

Thorax: Generally grayish tan and immaculate; dorsum concolorous with pleural areas. Femora dark except at apices, dusted gray; tibiae mostly dark; hind tibia with considerable pallor at apex; tarsi mostly pale, yellowish orange. Setal fascicle of hind basitarsus dark. Wing ratio 1:0.43; costal vein ratio 1:0.45; M1+2 vein ratio 1:077.

Abdomen: Concolorous with thorax in general but with darker areas toward the anterior margin of each segment. The abdomen was removed before measurements were taken. Male genitalia as in diagnosis and in Figures 32–33.

TYPE-MATERIAL.—Holotype male: “Reindeer Depot Mackenzie Delta 17–VIII–1948 J. R. Vockeroth/HOLOTYPE Notiphila pallicornis Mathis (red).” Reindeer Depot is in the Northwest Territories, Canada. The type will be deposited with the Canadian National Collection, Ottawa, type number 15761.

ETYMOLOGY.—The epithet pallicornis is a combination of the Latin adjective pallidus (“pale” or “dim”) plus the noun cornu (“horn”) in reference to the distinctively pale antennae.

GEOGRAPHIC DISTRIBUTION.—Notiphila pallicornis is known only from the type-locality, Reindeer Depot, Mackenzie Delta, Northwest Territories.