Sphecomyia pattonii Williston, 1882

M. Moran, Kevin & H. Skevington, Jeffrey, 2019, Revision of world Sphecomyia Latreille (Diptera, Syrphidae), ZooKeys 836, pp. 15-79 : 39-40

Sphecomyia pattonii Williston, 1882 Figs 2J, 7F, 8F, 9F, 11B, 20B, 25

Sphecomyia pattonii Williston 1882b: 328 - Kertész 1910: 349; Vockeroth 1965: 86; Stone et al. 1965: 613; Weisman 1965: 268, 1966a: 53, 1966b:194; Boyes and van Brink 1967: 432, 1970: 212; Cole and Schlinger 1969: 331; Telford 1975: 21; Hippa 1978: 15. Type locality. "Washington Territory". [USNM]

Calliprobola calorhina Bigot 1884: 353 - Williston 1887: 258. Type locality. "Washington Territory". [UMO]

Sphecomyia pattoni Williston 1886: 258 - Aldrich 1905: 404; Osburn 1908: 14; Shannon 1925: 43; Curran 1932: 8.

Diagnosis.

Species similar to S. columbiana , S. cryptica sp. n., S. dyari , S. hoguei sp. n. and S. oraria sp. n. but can be distinguished by the following characters: tergite 1 with uninterrupted, pruinose band along posterior margin; scutellum black pilose; ventral calypter with long black pile; sternites 2 to 4 mostly pruinose, with narrow anterior border and transverse subapical band shiny to dull black.

Redescription.

Male. Body length: 12.1-16.0 mm. Wing length: 8.3-11.8 mm. Head. Face yellow pruinose with shiny, black, medial vitta extending from oral margin to base of antenna; frons broad, about as long as broad at antenna, two-thirds as broad at vertex as at antenna, bare, with yellow pruinosity along posterior fourth; vertex triangular, longer than broad, shiny, with ocellar triangle black pilose; postocular border yellow pruinose; postocular pile black, occipital pile yellow; male narrowly dichoptic; antenna black, black pilose, with length of segments roughly in a 3:3:2 ratio.

Thorax. Sub-shiny black; postpronotum yellow pilose with occasional black pile; scutum and scutellum mostly black pilose with occasional yellow pile; postalar callus mixed black and yellow pilose; proepimeron, posterior anepisternum yellow pilose; posterior katepisternum yellow pilose with broadly separated patches; anterior anepimeron yellow pilose; metasternum yellow pilose; postpronotum, anterior fourth of scutellum, broad posterior margin of anepisternum and dorso-posterior corner of katepisternum yellow pruinose; area between postpronota yellow pruinose, except shiny medially; anepimeron shiny; scutum without pruinose vittae; ventral calypter with long black pile.

Legs. Foreleg black, except extreme apex of femur and anterior third of tibia reddish-yellow; fore tarsi slightly broadened; midleg reddish-yellow, except basal four-fifths of femur and last two tarsomeres black; hind leg reddish-yellow except last two tarsomeres black; legs yellow pilose, except fore tibia, fore tarsi, apex of fore femur and last two mid and hind tarsomeres black pilose; hind coxa yellow pruinose.

Wing. Hyaline; microtrichia absent from following areas: cell bc; cell r1 from base almost to crossvein r-m; broad basal portion of cell br (before origin of M) and about basal two-fifths of narrower portion of this cell (caudad of spurious vein only); cell bm except apex and narrow anterior and posterior margins of about apical fourth; broad anterior margin of cell cua; narrow, elongate, oval area proximal to vein A1.

Abdomen. Tergites and sternites shiny to sub-shiny, black with yellow pruinose markings as follows: tergite 1 pruinose along posterior margin; tergite 2 with broad, interrupted, narrowing medial band which meets a narrow, uninterrupted posterior band in the posterolateral corners of tergite; tergite 3 with similar, but truncate, medial band more narrowly interrupted; pattern on tergite 4 same as tergite 3 except medial band very narrowly or incompletely interrupted; sternite 1 shiny; sternites 2 to 4 mostly pruinose, each with narrow anterior border and transverse subapical band shiny to dull black; sternites 6 to 8 pruinose; pile of abdomen yellow, except sometimes with scattered black pile present on postabdomen.

Male genitalia. Surstylus elongated, about 1½ times as long as broad, curving upward dorsally; pile on dorsal surface of surstylus, increasing in length posteriorly; minute spines on ventral surface of surstylus, with apical three-fourths of lateral inner surface also with spines; basal fourth of the ventral surface of the surstylus produced into a lobe directed anteriorly, with minute pubescence on ventral and lateral inner surface; cerci rounded, with no invagination on posterior border; aedeagus as in Fig. 2J.

Female.

Similar to male except normal sexual dimorphism.

Distribution.

U.S.A.: Washington, Oregon, Idaho, Montana. Canada: British Columbia (Fig. 25). Widespread throughout coastal and mountainous areas of Washington state except seemingly absent from the Columbia basin. Extends into coastal and forested parts of northeastern Oregon. Extends north into forested coastal and inland areas of British Columbia. Also known from forests of northern Idaho and western Montana.

Biology.

The authors collected this species visiting Rubus L. sp. on a forested slope near a river. Also collected visiting flowers of Heracleum lanatum Michx. Known hilltopper. Recorded flying late April through mid-August, with one outlier from mid-October.