Dilophus disagrus ( Speiser, 1910 )

Skartveit, John & Freidberg, Amnon, 2023, Revision of the genus Dilophus Meigen, 1803 (Diptera, Bibionidae) from the Afrotropical Ecozone, Zootaxa 5360 (3), pp. 301-354 : 318-319

Dilophus disagrus ( Speiser, 1910)

Philia disagra Speiser, 1910

Type locality: TANZANIA, Kilimanjaro, Kiboscho, 3800–4000m, ii. 1906, Swedish Zoological Kilimanjaro and Meru expedition. Hardy (1951a) did also mention Meru as a locality, but did not list any specimens from this area. The original description ( Speiser 1910) mentioned one male and one female specimen, both from Kilimanjaro.

Holotype (male) supposed to be in Naturhistoriska Riksmuseet, Stockholm, but could not be found (Yngve Brodin, pers. comm.). We have not been able to locate any material of this species.

Previous records: Tanzania ( Speiser 1910).

Diagnosis: A medium-sized species. It differs from all other afrotropical species by having a yellowish-white, not brownish, haltere.

Description based on Speiser (1910) and Hardy (1951a)

Male: Body length 3.75–4.25 mm.

Head: Black, rostrum pale yellow. Somewhat longer than wide. Antennae and palpi black with fine chiefly yellow pile. First flagellomere wider than other segments.

Thorax: Dorsally black and shiny, humeri reddish-yellow, pleura grayish rufous. Pile fine and yellow-white. Thoracic spines reddish. Haltere yellowish-white.

Legs: Coxae and femorae reddish yellow, tibiae and tarsi black. Pile whitish-yellow. Fore coxa anteroventrally with sharp corner. Protibia mesally with 4 spines, apically with circlet of 8 spines.

Wing: Yellowish-brown fumose, pterostigma pale and indistinctive. R-veins and stem of M yellowish-brown, posterior veins a little paler. Crossvein R-M a little shorter than distal segment of M.

Abdomen: Black with yellowish-white pile.

Female:

Head: Reddish- to yellowish-brown, as wide as long. Antennae yellowish, flagellum 8-segmented.

Thorax: Yellowish-red, spine rows black. Scutellum dark brown to black with numerous fine, pale marginal setae. Haltere yellowish-white.

Legs: protibia brownish-red to blackish, otherwise yellowish-red. Protibia with 4 spines in a straight row mesally.

Wing: Faintly fumose, veins pale yellowish throughout. Pterostigma invisible. Costa extends to 0.3* distance between apices of R 4+5 and M 1.

Abdomen: Reddish-yellow with pale pile.

Distribution and ecology: The species is apparently alpine and has been collected at altitudes of 3000–4000 m. It appears to be confined to the mountains of northern Tanzania, possibly endemic to the Kilimanjaro massive. The available records are ambiguous with respect to the amount of material that has been available of this species, e.g. Meru is mentioned as a locality by Hardy (1951a) but not in the original description, the original description did mention only one male specimen but gave the body length as a range, not a single figure.

Flight period: The species has been collected in February ( Speiser 1914).