Longibeccus imperator (Oldroyd) Scarbrough, 2010

Scarbrough, A. G., 2010, An overview of the Afrotropical Ommatiinae (Diptera: Asilidae) with a key to genera, Zootaxa 2540, pp. 1-47 : 17-19

publication ID




persistent identifier


treatment provided by


scientific name

Longibeccus imperator (Oldroyd)

comb. nov.

Longibeccus imperator (Oldroyd) View in CoL , new combination.

Figs. 41 –51,108

Ommatius imperator Oldroyd, 1939: 45–46 View in CoL ; Hull 1962: 436; Oldroyd 1980: 347. Catalogue.

Redescription, male. Body 15.0– 18.3 mm; wing, 14.1–16.1 mm. Head: Dorsal 1/2 of face mostly brown tomentose with sparse, mostly yellow setae with 6–7 brown thin brown bristles; ventral 1/2 of face produced, slightly rounded; gray tomentose with numerous thin whitish bristles ventrally, 6–8 slightly thicker brown bristles more dorsally; FHWR 1.0:5.6–1.0:6.3. Palpus brown with brownish-yellow basally, setae yellow, sparse, thicker brown setae apically. Proboscis long, as long as vertical length of compound eye, narrow vertically, higher than wide, lancet-like to pointed apex. Antenna (as in Fig. 3) brown or pale brownishyellow, flagellum dark, pedicel paler; setae brown or blackish; flagellum cardiform, wider basally than either pedicel or scape, about twice as long as pedicel; surface with few to several large punctations; FWLR 1.0:1.6– 1.0:1.8. Frons yellowish-brown tomentose with a row of short, thin, black setae, longest setae slightly shorter than scape. Vertex moderately deep; ocellar tubercle narrow and tall, dorsally at or just before top of head with 2 long setae and shorter, thinner, sparse black setae. Occiput largely yellow to yellowish-gray tomentose, margin of eye and ventral 1/2 of occiput pale yellowish-gray tomentose; occiput with mostly black or brown setae dorsally, those ventrally mostly white; a row of long, thin, black postocular setae extend to mid-lateral margin of head; longest setae proclinate with apices about 1/2 distance to ocellar tubercle.

Thorax: Pronotum brown with mostly black setae and 4 thin, longer setae-like bristles; tomentum brown. Mesonotum yellow, wide longitudinal stripes, divided anteriorly, and 2 black spots laterally; tomentum mostly brownish, dark on stripes and lateral spots, yellowish-brown between stripes and spots, golden yellow laterally with mostly thin blackish setae; 5 lateral and 6 thin dorsocentral bristles, the latter behind transverse suture. Scutellum black dorsally, narrow apical margin yellowish-brown, brownish tomentose, black setose; 2 blackish marginal bristles and deep preapical groove present. Mediotergite black, anatergite reddish-brown or yellow. Pleuron black, with mostly dark brown and yellow or reddish tomentum before wing, vestiture mostly or entirely black; anepimeron with several, long, thin setae, 1 quite long, slightly bristly. Halter reddish. Wing ( Fig. 41): Cells slightly corrugated anteriorly; veins yellow; microtrichia dense, sparse at extreme base, mostly yellow, brown from base of cell r 4 to apex. Base of cell r 4 beyond apex of cell d. Crossvein r-m at apical 1/3 of cell d, much longer than CuA 1 +M 3. Base of m 1 narrow, much wider to wing margin with vein M 1 strongly arched basally, m 1 WR 1.0:4.0:3.4–1.0:4.5:4.2. Leg: Coxae dark; Ivory Coast specimen with prothoracic coxa yellow, mesothoracic coxa yellow with black spot anteriorly, and narrow anterior of metathoracic coxa yellow; vestiture abundant, white to yellow. Trochanter brown. Femora color variable with short blackish setae and stout black bristles; pro- and mesothoracic femora with basal 1/3–1/2 brown, yellow apically; metathoracic femur brown on apical 1/3–1/2 dorsally, yellow basally; femora with abundant, mostly yellow, setae. Prothoracic femur mostly black setose ventrally, none forming ventral row. Mesothoracic femur with 2 anterior and 3 wide spaced anteroventral bristles; 1 thick posteroventral bristle on apical 1/3. Metathoracic femur with 5 anterior and 8–9 anteroventral bristles; mostly yellow posteroventral setae, apical 1/2 with 2–3 bristles plus 1–3 setae; basal 2–3 setae longest; MFWLR 1.0:4.0–1.0:5.3. Tibiae with abundant, rather long, yellow setae and black bristles. Prothoracic tibia yellow, apex brown, with row of long posteroventral black setae and 2 long ventral bristles. Mesothoracic tibia mostly brown, basal 1/3–2/3 yellow. Metathoracic tibia mostly brown, basal 1/5 yellow. Tarsi with black bristles; basal 4 tarsomeres of pro- and mesothoracic tarsi yellow, apices brown; apical tarsomere brown, narrow base yellow. Metathoracic tarsi mostly brown, basal tarsomeres usually yellowish-brown basally.

Abdomen: Black with mostly brown tomentum, tergites 1–3 yellowish-gray or gray tomentose apically; mostly or entirely brown setose, setae long laterally and ventrally, sparse yellow setae mixed laterally on tergites and sometimes on sternites. Segments 7–8 shiny black. Terminalia ( Figs.42–47): Blackish, setae yellowish. Epandrium with deep, wide U-shaped apical notch, and 2 long arms; dorsal arm narrow, ventral arm strongly spatulate. Gonostylus slender, similar to an inverted leg and apical foot, shaft slightly twisted. Aedeagus with large cupped epiphallus, concealing unusually thin sigmoid distiphallus; aedeagal apodeme short, about as long as aedeagal sheath. Gonocoxite triangular with deep concavity laterally between apical corners. Hypandrium narrow, pointed apically extending forward between bases of gonocoxite.

Female. Body 17.5 mm; wing 15.8 mm. FHWR 1.0:5.6; FWLR 1.0:1.8. Thorax: Pronotum with 4 short bristles. Legs: Prothoracic femur dorsally with 3–4 long setae. Mesothoracic femur with only 2 anteroventral bristles; apical 1/2 of mesothoracic femur with1 posteroventral and 2 posterior bristles. Metathoracic femur with 4 bristles anteriorly. Abdomen: Tergites 6–7 and apical margin of 5 shiny, without brown tomentum, several long, black setae present laterally; sternites with mostly long black setose sternite 7 apically with 6–7 black bristles. Tergite 8 narrow, telescoped below tergite 7. Terminalia ( Figs. 48–51): Tergite 9 fused with base of cercus, curved downward, forming a cup-like recess ventrally; several setae laterally. Cerci fused, lacking distinct membranous lines medially, membranous basomedially. Ventral lamellae fused basally along median line. Sternite 7 with angular apical corners, apical margin somewhat horizontal medially. Spermatheca short, oval. Genital fork membranous, only apical 1/2 of arms darkly sclerotized; base broadly round.

Types examined. UGANDA: (Holotype ♂; paratypes 2 ♂, 1 ♀, BMNH); (paratype ♂, OXUM) .

Other specimens examined: IVORY COAST: Tai 25.iv.1979 / G. Couturier / Forêt Dense / humide / Semperviren / sous dios Forêt Primaire (1 ♂, MNHN) .

Distribution. Africa ( Uganda, Ivory Coast). Adults are associated with forests in April ( Ivory Coast) and October ( Uganda).

Remarks. Large, dark brown species with a long robust, flattened proboscis, unusually large flagellum with punctations, mesonotum with a wide dark longitudinal stripe divided anteriorly, a dark elongate spot on each side, and golden yellow tomentum laterally, largely yellow microtrichose wings, brown beyond base of cell r 4; presence of a stout black, posteroventral bristle on the apical 1/3 of the mesothoracic femur; and terminalia ( Figs. 42–51) characterize the species.

Type specimens are in fair condition. The flagellum and style are absent on the holotype and 1 male paratype in BMNH; the head of the latter is glued to a tag below the specimen. The holotype labels include: [Circle] Holotype ~ [circle] type ~ [rectangle] Uganda / Toro / Daro or Durro Forest, [0 o 20’N 32 o 34’E] / 25–29.x.1911 4000–4500 ft. [= 1220–1386 m] / S.A. Neave ~ pres. By Imp. Bur. E. / 1921-12 ~ Ommatius ♂ / imperator sp. no.[v]. / H. Oldroyd det. 1938. BMNH paratypes: [1] labels include: [Circle with yellow border] Paratype [above], ‘ Omm. imperator / Oldr. [below] ~ [rectangle] Uganda / Prot. / Daro or Durro Forest, [0 o 20’N 32 o 34’E] / Toro 4000–4500 ft. [= 1220–1386 m] / 25–29.x.1911 / S.A. Neave ~ 1912-193 ~ Ommatius ♂ / imperator / Oldr. / det. H. Oldroyd 1939; paratype [2] labels include: [Circle yellow border] Paratype / ♂ ~ [rectangle] Uganda / Prot. / Southern Daro / Mbarara [0 o 36’S 30 o 39’E] / Ft. Portal Rd. ~ 3800–4200 ft. [= 1158–1280 m] / 22–24.x.1911 / S.A. Neave ~ 1912-193 ~ det. Ommatius imperator Oldr. / det. H. Oldroyd 1939; [3] paratype labels same as paratype [1] except [circle yellow border] Paratype ~ [circle red border] ♀ / type [above], ‘ Om. imperator / Oldr.’[below] ~ Pres. by / Imp. Bur. Ent. / Brit. Mus. / 1923-58 ~ Ommatius ♀ / imperator Oldr. / det. H. Oldroyd 1939. OXUM paratype labels include: Circular [margib yellow] with word ‘paratype’ above, Omm. / imperator / Oldr below ~ Ommatius imperator sp. nov / [♂] H. Oldroyd Det 1938’ ~ K with ‘prey / Oct 1937 / W. Uganda, Ankole, Kalinzu For. F (Forest) [0 o 38’S 30 o 35’E] / El. 4700–5000 ft. [= 1434–1525 m] / T.H.E. Jackson 574 / 1938.


Museum National d'Histoire Naturelle














Longibeccus imperator (Oldroyd)

Scarbrough, A. G. 2010

Ommatius imperator

Oldroyd, H. 1980: 347
Hull, F. M. 1962: 436
Oldroyd, H. 1939: 46
Darwin Core Archive (for parent article) View in SIBiLS Plain XML RDF