Ditrichophora canifrons Cresson

Mathis, Wayne N. & Zatwarnicki, Tadeusz, 2012, A revision of the New World species of Gymnoclasiopa Hendel (Diptera, Ephydridae), ZooKeys 248, pp. 1-69 : 47-50

Ditrichophora canifrons Cresson stat. rev. Fig. 58

Ditrichophora canifrons Cresson 1926: 250; 1942: 121 [review]. Wirth 1965: 739 [Nearctic catalog]. Steyskal 1972: 129 [habitat on tree trunks].

Gymnoclasiopa canifrons . Mathis and Zatwarnicki 1995: 176 [generic combination, world catalog]. Chandler 2012: 17 [list, Maine].

Diagnosis.

This species is distinguished from congeners by the following combination of characters: Small to medium-sized shore flies, body length 1.85-3.25 mm; head and thorax generally microtomentose gray dorsally, abdomen subshiny to shiny black. Head: Frons moderately microtomentose, cinereous to whitish; proclinate fronto-orbital setae 2, length of anterior seta about 1/2 that of posterior seta, inserted far anteriad, distance between proclinate setae subequal to that between posterior seta and medial vertical seta. Antenna generally yellowish orange (sometimes apex of basal flagellomere and scape darkened); arista bearing 7-8 dorsal rays. Face rather flat; antennal grooves, especially ventral margins, poorly defined, not conspicuous; face slightly whitish gray dorsally, dorsal portion shallowly carinate between shallow antennal grooves, thinly, microtomentose, becoming blackish, less microtomentose ventrally; facial setae inserted close to parafacials, aligned vertically; gena short, less than height of basal flagellomere; gena-to-eye ratio 0.08-0.09. Maxillary palpus black. Thorax: Mesonotum moderately microtomentose, cinereous, similar to frons, not shiny; pleural areas from ventral notopleural suture ventrad black, contrasted with whitish gray mesonotum, similar to black abdominal tergites. Wing lacteous; costal section II conspicuously longer than costal section III; costal vein ratio 0.47-0.65; M vein ratio 0.54-0.57; halter stem yellowish tan to yellow, knob yellowish white to white. Femora black; tibiae black except for basal and apical extremities black; tarsi mostly yellowish orange. Abdomen: Tergites subshiny to shiny, black. Male terminalia: Epandrium in posterior view as an inverted U, narrowed dorsally, each lateral arm shallowly curved; cercus in posterior view semilunate with dorsomedial, narrow extension; aedeagus in lateral view longer than wide, truncate apically, in ventral view as wide as long, shallowly and angularly emarginate apically; phallapodeme in lateral view with elongate, narrow, process to base of aedeagus, and much shorter, digitiform process toward hypandrium, 1/3 length of longer process, in ventral view robustly T-shaped with thick stem, base as wide as cross bar; gonite (probably the postgonite) elongate, wide basally, narrowed to elongate, narrow process bearing 2 posterior setulae and 1 anterior, subapical setula; hypandrium in lateral view bowl shaped, posterior portion slightly more extended, in ventral view with anterior margin broadly curved and deeply emarginate.

Type material.

The holotype male of Ditrichophora canifrons Cresson is labeled "Jack Run, Allegheny, VI,14,08,Pa./♂/302/TYPE No. 6301 Ditrichophora CANIFRONS E T Cresson, Jr. [red; species number and name handwritten]." The holotype is double mounted (minuten pin in a rectangular card), is in excellent condition (some cephalic setae missing or misoriented), and is deposited in the ANSP (6301).

Type locality. United States. Pennsylvania. Allegheny: Jacks Run (40°29'N, 80°03'W).

Other specimens examined.

Canada. QUEBEC: Quebec City (46°48.2'N, 71°14.6'W), 5 Aug 1930, A. L. Melander (1♂; ANSP).

United States. MAINE. Hancock: Schoodic Peninsula (SERC Campus; 44°20.5'N, 68°03.7'W; lot 95), 16 Jul 2006, D. and W. N. Mathis (1♀; USNM).

MARYLAND. Montgomery: Bethesda (38°58.8'N, 77°06'W), 14 Jun-25 Aug 1965, 1971, 1974, G. C. Steyskal (16♂, 1♀; USNM); Cabin John (38°58.5'N, 77°09.5'W), 25 Jul 1972, G. C. Steyskal (19♂; USNM); Rockville (39°05.1'N, 77°09.2'W), 30 May 1969, G. C. Steyskal (1♀; USNM).

NEW YORK. Ulster: Beaver Kill (42°06.7'N, 73°59.2'W), 12 Aug 1909, E. T. Cresson, Jr. (1♂; ANSP).

NORTH CAROLINA. Mitchell: Penland (35°55.8'N, 82°06.7'W; 915 m), 17 Jun 1957, G. C. Steyskal (2♀; USNM).

OHIO. Lawrence: Vesuvius Lake (38°34.8'N, 82°37.5'W), 23 Aug 1974, J. Regensburg (1♀; USNM). Preble: Hueston Woods (39°26.9'N, 84°45'W), 25 Jun 1975, J. Regensburg (1♂, 1♀; USNM); Rush Run Wilderness Area (39°34.6'N, 84°37.9'W), 1 Jul 1979, J. Regensburg (1♀; USNM). Wayne: Rittman Salt Works (40°58.2'N, 81°45.7'W), 30 Jun 1977, B. A. Steinly (1♂; USNM).

PENNSYLVANIA. Allegheny: Jacks Run (40°29'N, 80°03'W), 14 Jun 1908 (5♂, 4♀; ANSP). Mifflin: Lewiston (40°33.6'N, 77°38'W), 7 Jun 1940, A. L. Melander (1♀; USNM). Wilkes-Barre: Mineral Spring (41°15.3'N, 75°50.5'W), 5 Sep 1927, A. L. Melander (1♂; USNM).

TENNESSEE. Sevier: Arch Rock (35°38.1'N, 83°26.3'W), 28 Jun 1941, A. L. Melander (4♂, 5♀; USNM); Chimneys (35°38.2'N, 83°29.3'W), 25 Jun 1941, A. L. Melander (4♀; USNM).

VIRGINIA. Fairfax: Fairfax (38°50.5'N, 77°18.5'W), Jul 1954, M. R. Wheeler (1♂, 3♀; USNM); Lake Barcroft (38°50.9'N, 77°09.4'W), 28 May 1977, W. N. Mathis (12♂, 13♀; USNM); Turkey Run (mouth; 38°57.9'N, 77°09.4'W), 21 Jun 2006, W. N. Mathis (1♀; USNM). Independent City: Falls Church (38°52.9'N, 77°10.3'W), 13 Jul 1954, W. W. Wirth (1♀; USNM).

WEST VIRGINIA. Hardy: Lost River State Park (38°55.6'N, 78°53.6'W), 19 Jun 1977, L. V. Knutson (2♀; USNM); Lost River State Park (38°53.8'N, 78°55.7'W; 615 m), 20 Jun-13 Jul 2007, D. and W. N. Mathis (1♂, 9♀; USNM). Pocahontas: Tea Creek (Right Fork; 38°20'N, 80°9.9'W), 29 Jul 1982, O. S. Flint, W. N. Mathis (4♂, 5♀; USNM). Ritchie: North Bend State Park (39°13.4, 81°06.6'W), 23 Jun 1970, G. C. Steyskal (1♂; USNM).

Distribution

(Fig. 58). Nearctic: Canada (Quebec), United States (Maine, Maryland, New York, North Carolina, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia).

Remarks.

Although uncommon, this species is widespread in the Mid-Atlantic states, occurring along the coastal plain through the Piedmont and Blue Ridge to the Alleghany.

The mostly yellowish antenna, especially the pedicel in lateral view (all yellow except for the dorsum), and apex of the foretibia distinguish this species from Ditrichophora cana . Structures of the male terminalia, especially the shape of the aedeagus, as described above, are also diagnostic.