Usia lata Loew, 1846

Gibbs, David, 2014, A world revision of the bee fly tribe Usiini (Diptera, Bombyliidae) Part 2: Usia sensu stricto, Zootaxa 3799 (1), pp. 1-85 : 36-39

Usia lata Loew, 1846

( Figure 8 , Plate VII)

Usia lata Loew, 1846: 407 .

Type material examined. LECTOTYPE here designated; Greece, Makri Mai [18]42/ Coll. H. Loew/ Typus / Zool. Mus. Berlin [♂ in ZMHB ]; PARALECTOTYPES; Greece, Makri Mai [18]42/ Coll. H. Loew/ Typus / Zool. Mus. Berlin [5♂ 5♀ in ZMHB ]; Makri Mai [18]42/ Usia lata m/ 9694/ Coll. H. Loew/ Typus / Zool. Mus. Berlin [♂ in ZMHB] ; [ small blue square]/ Coll. H. Loew/ Typus / Zool. Mus. Berlin [♂♀on same pin, in ZMHB] ; [small pink square]/ Coll. H. Loew/ Typus / Zool. Mus. Berlin [2♀ in ZMHB] ; Makri Mai [18]42/ Usia lata / Schiner 1869/ Typus / Zool. Mus. Berlin [♀ abdomen and wing glued to separate cards on pin in ZMHB]; Makri Mai [18]42/ [gold square]/ lata Lw / Type / Schiner 1869/ lata det. Becker ♀ [1♀ in NMW] ; Makri, Mai [18]42/ Coll., Loew/ U. lata, Rhodus [1♀ in TAU]; Rhodos [Rhodes]/ lata / sec. typ.: Loewii/ U. lata Ex coll. Kow. [1♀ in OUMNH].

Other material examined. Originally described from an unspecified number of specimens. Twenty syntypes were found, 17 in ZMHB, one in OUMNH, one in NMW and one in TAU. The original depository of Loew’s European types was ZMHB so a male in good condition was selected from this series as the lectotype.

Greece, Evros, Avas , N40°58′17" E25°54′ 31″, 130m, 7 June 1997, 1♀ (leg. J. Dils) ; Argolida , Skotini , N37°47′50″ E22°26′16″, 1000m, 15 June 1997, 3♂ 9♀ ; Rodopi , Nea Sanda , N41°07′26″ E25°53′54″, 700m, 8 June 1999, 1♀ (leg. J. Dils & J. Faes) ; Epiro , 2000m, Mte Timfi , 1 July 1982, Osella [♀]. Turkey, Mulga , Marmaris , N36°50′51.3″ E28°14′34.2″, 50m, 15 May 1999, 1♂ 7♀ ; Tokat , Sarigöl , N38°11′05″ E28°41′04″, 650m, 10 June 1999, 1♀ ; Mulģa , Reşadiye Yarimadasi , N36º41′09″ E27º26′36″, 130m, 26 April 2001, 19♂ 16♀ ; Kayseri , Erciyes Geçidi , N38°36′43.7″ E35°31′7.8″, 1870m, 4 July 2004, 12♂ 8♀ (leg. J. Dils & J. Faes) ( PCJD).

Etymology. From the latin for “wide”, probably referring to the relatively broad abdomen.

Diagnosis. Very variable in size, Greek specimens tending to be large, Turkish ones medium sized to small. Usually shining black species, sometimes with faint blue, greenish, or coppery reflections on abdomen, and short to exceedingly short, erect whitish vestiture. Head small compared to thorax, occiput densely grey dusted, frons relatively broad, separated by more than distance across lateral ocelli, shining black medially. Mesonotum relatively broad, domed, vestiture short, in some specimens so sort as to be almost invisible, cuticle clearly punctured, shining, almost smooth between punctures. Wings usually with distinctly brown infuscation to level of crossvein r-m, base sometimes yellower. Tergites strongly undulating, raised transverse ridge medially and strongly upturned apical margin. Genitalia typical of group, differing only subtly from close congeners; epandrium with entire apical margin; furca with tip rounded.

Redescription. Measurements. Body length. 4.3–9.0mm. Wing length. 4.0– 7.3mm.

Male. Head. Oral margin broad above, narrowing sharply at insertion of proboscis and disappearing below ( Greece) or narrow, also disappearing below ( Turkey), shining black. Frons shining black, conspicuously greydusted anterolaterally, area in front of anterior ocellus depressed. Eyes separated at their narrowest by about one fifth head width, noticeably more than width across lateral ocelli inclusive. Lateral ocellus separated from the eye margin by almost twice the diameter of that ocellus. Ocellar tubercle shining, undusted, eye margins in front of anterior ocellus diverging relatively evenly to rear of oral opening. Translucent white hairs on ocellar tubercle averaging about the width across the lateral ocelli, significantly shorter than the width of the frons, rear of frons in front of anterior ocellus entirely hairless, anterior part of frons with a scattering of short setulae, most on the dusted areas, hairless medially. Occiput densely grey dusted, the black ground colour obscured except on a triangular area behind ocellar tubercle which is shining black. A fairly dense covering of white to pale yellowish hairs across dusted area, shorter and more even above, significantly longer close to lower oral margin. Ommatidia uniform in size across the eyes. Antennae black, third segment, a little less than twice length of scape and pedicel together, narrow swollen below basally, concave medio-ventrally, sensilla inconspicuous, translucent brownish. All antennal segments with very short, erect brown hairs above, longest just before apical sulcus. Palps small, black, apically, clavate tip a little narrower ( Greece), or wider ( Turkey) than oral margin, the brown apical setae about half as long as the length of the palps. Proboscis shorter than head-thorax length, black, dorsally hairless. Thorax. Mesonotum shining black, narrowly grey dusting on anterior slope of mesonotum laterally, post-pronotal lobe, notopleuron narrowly and above wing root. Disc distinctly punctured, the punctures well defined, circular, the majority separated by one to three times the diameter of a puncture, the cuticle between punctures smooth and shining, any wrinkling not obscuring the punctures. Mesonotal hairing short, shorter than distance between lateral ocelli ( Greece) or very short, on disc shorter than distance between punctures, hairs only visible under high magnification ( Turkey) ( Figure 8 ). Paramedian vittae inconspicuous, usually just discernable by their sparser puncturing and more obvious transverse wrinkling, fading out well before wing insertions. Acrostichal hairs between the bare paramedian vittae multiserial, reclinate or almost invisible, dorsocentrals not distinguishable from the general vestiture. Scutellum surface sculpture and vestiture as adjacent parts of mesonotum, often more deeply transversely wrinkled. Pleurae uniformly grey dusted largely obscuring ground colour, no areas of shining cuticle. Relatively long white hairs, longer than any on mesonotum, on pronotum and upper and posterior half of the anepisternum. Wing. Membrane brown tinged, a brown infuscation covering much of wing from humeral crossvein to tip of r1, to r4 and r5, first basal cell and less intensely much of discal cell, second basal cell and base of m3, proximal to basal cells either yellower ( Greece) or brown infuscated as centre of wing ( Turkey), squama very pale yellow, the veins all brown, usually yellower basally in Greek specimens. Crossvein r-m at or a little beyond, less often a little before the middle of discal cell, conspicuously beyond dm-cu. Anal lobe moderately well developed, with evenly curved trailing edge, about as two-thirds width of anal cell. Haltere. Yellow, base of stem slightly brownish. Legs. Coxae black with a coating of grey dust like that on the pleurae. Remainder of legs black, undusted, shining below the setulae. Coxae externally and femora ventrally covered with fairly short, white hairs, on the femora as long as the greatest depth of the tibia. Femora dorsally and tibia rather densely covered with short, recumbent, white hairs. Abdomen. All tergites shining aeneous black, sometimes with bluish, coppery or greenish reflections, first tergite dusted on down-curved lateral margin, succeeding tergites more thinly and inconspicuously dusted. Each tergite densely puncto-rugose, surface sculpture of transverse welts each furnished with a very short hair, each tergite conspicuously undulating, a strongly raised transverse ridge medially, smooth, shining apical margin sharply reflexed. Disc uniformly and densely covered with very short, pale brownish, recumbent hairs ( Greece) to almost naked on disc ( Turkey) longer, whiter and more erect laterally. Sternites grey dusted, faintly punctate, with sparse, erect white to very pale yellow hairs. Genitalia. Relatively small and simple, globular. Epandrium short and broad, apicolateral extensions short, apical margin entire, lacking a median ‘V’-notch, mostly shining black, the cuticle punctate evenly coated with pale yellow curved hairs. Gonocoxite about twice as broad as long, shining black basally, yellow-brown apically, the tips clearly diverging, haired as epandrium, gonostyli simple, curved with basal ‘thumb’.

Female. As male except as follows: oral margin slightly broader in respective populations, in lateral view visible right to rear of oral opening. Frons a little wider, and diverging a little more, lateral ocelli separated from eye margin two to three times their diameter. Dusting of frons a little more conspicuous and extensive, just visible extending down between eye and oral margin. Mesonotal vestiture even shorter. Genitalia. Tip of abdomen coming to a rounded point; apical sternite rather rectangular, relatively broad, apical notch conspicuous and relatively wide. Main part of apical sternite with raised basal boss clothed with long whitish hairs. Furca typical of the group, rounded tip sclerotised, arms long, conspicuous rectangular, dark-pigmented vaginal plate.

Discussion. The details of male genitalia suggest that U. lata is most closely allied to U. bicolor Macquart and its sibling species U. crinipes Becker. A variable species with two distinct forms in Greece and Turkey respectively. These populations differ only in relative length of vestiture, average size and width of oral margin. These small differences do not seem sufficient to separate then as distinct species.

Distribution. Greece (including Peloponnese, Rhodes and Lesbos), western half of Turkey.

Figures

FIGURE 8. ♂ U. lata head and mesonotum dorsal.