Rachicerus fulvicollis Walker 1854

Rachicerus fulvicollis Haliday (PL III, fig. 18)
1854. Rachicerus fulvicollis Haliday, in Walker's List Dip. Brit. Mus. v, p. 104. 1877. Rachicerus ruficollis Osten Sacken, Bui. U. S. Geol. Sur. in, p. 212 [Evidently a mistake in name for fulvicollis.] 1905. Rhachicer us fulvicollis Aldrich, Cat. N. Am. Dip., p. 212.
Head and abdomen blackish ; thorax yellowish brown ; legs and halteres yellowish; wings slightly tinged with brownish, especially at apex; antennae serrate with twenty-one to twenty-two segments (female), subpectinate below with twenty-eight to thirtyfive segments (male).
Male. — Length, 5 mm. Head: Front polished, black, narrow, only about the width of the ocellar tubercle and with sides parallel; palpi and proboscis small, pale yellow; antennae almost twice as long as thorax, shining black, the flagellum composed of about thirty segments, subpectinate, the processes being a little longer below than above.
Thorax: Mesonotum, scutellum, pleura, and metanotum brownish yellow, occasionally somewhat darkened on the metanotum which with the scutellum has
numerous fine pale hairs not readily seen except through the binocular; hal teres pale yellowish, apparently somewhat darker at base of knob.
Abdomen: Blackish, shining above and below with numerous short somewhat appressed pale hairs.
Legs: Wholly pale yellowish including coxae, the extreme tip of tarsi very slightly darkened; the legs wholly covered with fine, pale, short somewhat appressed hairs.
Wings: Membrane very slightly tinged with grayish, stigmal area brownish; veins dark brown.
Female. — Length, 6 mm. Differs from male as follows: antennae with about eighteen segments in the flagellum, the segments deeply serrate; abdomen somewhat tinged with brownish, hairs very small and fine; wing membrane slightly darker than in male.
Specimens Examined: Ii; 10 males, I female.
Massachusetts: i d Beverley, (Ed. Burgess), [U. S. N. M.].
Maryland: i d i 9, near Plummer's Island, July 26, 1916, (H. S. Barber), [U. S. N. M., the female is the allotype].
Virginia: 6 d Glencarlyn, July 8, 1915, (C. T. Greene), [U. S. N. M.]. 1 d (N. Banks), [A. N. S. P.].
Georgia: i d "South Georgia," (H. K. Morrison), [U. S. N. M.]