Usia atrata (Fabricius, 1798)

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 : 50-52

Usia atrata (Fabricius, 1798)

(Plate XII)

Voluccella atrata Fabricius, 1798: 570 .

Usia claripennis Macquart, 1840: 105 [1841: 383], syn. nov.

Type material of U. atrata examined. LECTOTYPE here designated; Morocco, Type / V. atrata, Mogador Schousboe/ ZMUC 0 0 503996 [♀ in ZMUC in almost perfect condition, only left mid-leg missing ]. PARALECTOTYPE; Morocco, atrata / Volucella , Marocco / ZMUC 0 0 503997 [♀ in ZMUC in poor condition, most of head and abdomen missing, left wing and all but left mid-leg missing].

Originally described from an undspecified number of specimens. Two of these were found in ZMUC, both females, one of them now severly damaged, the other in remarkable condition was selected as lectotype.

Type material of U. claripennis examined. LECTOTYPE; Algeria, Museum Paris, Env. D’Alger, Bové 126- 38/ 126, 38 [on reverse of round blue label]/ U. claripennis Macquart det. [in Macquart’s own hand][♂ in MNHN, in very good condition] . PARALECTOTYPES; Museum Paris, Env. D’Alger, Bové 126-38/ 126, 38 [on reverse of round blue label]/ TYPE / Usia claripennis [♀ in MNHN]; Museum Paris, Env. D’Alger, Bové 126-38/ 126, 38 [on reverse of round blue label]/ U. pusilla (H. Lucas det.?)/ claripennis Macq. , det. Becker [♀ in MNHN] .

Other material examined. Algeria, Aïn Sefra, South Oran, 1–18 May 1913, (W.R. & E.H.)/ atrata , 26 B [♀] ; Museum Paris, Mécheria, M. Pic 1928 [♀] ( MNHN). Morocco, Bou Jarif/Goulimine, N29º5′ W10º20′, 17 February 1992, ♂ ; 21 February 1992, ♀, leg. P.C. Matteson ( NMWC) ; 5 February 1992, ♂; 21 February 1992, ♂ leg. P.C. Matteson ( BMNH ex Greathead coll.) ; Agadir, Tamri, 215m, N30º45′47.4″ W 9º48′34.8″, 28 March 2006, 3♂ 5♀ ; Tiznit, El Merabtine, 70m, N29º20′6.1″ W10º8′18.4″, 22 March 2006, 2♂ 3♀ ; Arbaa-Sahel, 320m, N29º39′26.5″ W9º52′11.4″, 21 March 2006, 18♂ 30♀ ; Marrakech, Âit Ourirn, 530m, N31º34′37.2″ W7º49′52.4″, 6 April 2006, ♀ ; Oukaîmeden, 2200m, N31º14′0.6″ W7º49′1.4″, ♂♀ ; Tizi-n-Test, 1450m, N30º55′55.9″ W8º16′19.7″, 3♂ 5♀ ; Taroudant, Tizi-n-Test, 1200m, N30º48′13″ W8º23′43.8″, 29 March 2006, 2♂ ; Ingherm, 1660m, N30º2′54.3″ W8º27′18.1″, 26 March 2006, 5♂ 6♀ ; Timzit, 1700m, N30º5′7.5″ W8º29′58″, 26 March 2006, 2♂ 6♀ ; Tata, Iguiour, 1260m, N29º54′18.8″ W8º31′47.5″, 25 March 2006, 2♂ 4♀ ; Khemisset, Oulmes R 701, 700m, N33º31′37.8″ W6º54′23.8″, ♂♀ leg. J. Dils & J. Faes ( PCJD) ; Moyen-Atlas, Ifrane, June 1949 / 1949, L. Chopard/ Standing over, florea F., [♀].( BMNH Bowden coll.). Tunisia, Tabarka, Cap Negro oak forest, maquis, 15 May 1995, ♀ leg. M.J. Ebejer ( PCME) ; Zw. Maktar u. Thala, 910m, N35º30′ E9º1′, 29 May 1982, ♀ leg. E. Buttinger.

Etymology. atrata from Latin meaning “dressed in black”; claripennis from Latin clarus = clear and penna = wing, “clearwinged”.

Diagnosis. A usually large black species but variable in size, a relatively long-haired species of the Maghreb. All shining black, abdomen sometimes with faint blue and coppery reflections, occiput shining and undusted above, thinly dusted below, hairs on ocellar tubercle longer than width of frons at narrowest point, frons in front of anterior ocellus with long conspicuous hairs. Mesonotal vestiture long, all acrostichals reclinate, marginal scutellar hairs longer than mid-length of scutellum. Mesonotum and anepisternum almost devoid of dust, shining. Ventral hairs on hind femora longer than femora is deep. Wing with brown infuscation basally, veins brown, becoming blackish proximally, Genitalia small within the florea -group, with epandrium longer than wide, apicolateral extensions rounded; furca with tip pigmented.

Redescription. Measurements. Body length. 3.7–9.5mm. Wing length. 3.7–8.6mm.

Male. Head. Mouth-margin narrow, almost linear just close to rear of oral opening, shining black. Frons shining black, shallowly, transversely wrinkled laterally and with scattered punctures, narrowest a little in front of anterior ocellus, approximately one fifth head width, distinctly wider than width across lateral ocelli, lateral ocellus separated from eye margin by one and a half to two times the diameter of that ocellus. Frons grey dusted laterally on anterior third, the dust spots separated by an undusted area rather more than one third of the frons width at this point. Hairing long and abundant, on ocellar area clearly longer than width of frons at this point, pale yellow, these hairs contiguous with similar ones on laterally in several rows forward of anterior ocellus, shorter bet spreading across frons anteriorly. Occiput shining black above, thinly grey dusted centrally and below such that ground colour clearly evident. Pale yellow hairs covering occiput shorter than those on mesonotum above, similar in length below. Ommatidia uniform in size across the eyes. Antennae black, third segment about as long as scape and pedicel together, relatively narrow apically, swollen below basally, all segments with relatively long setae above especially on scape, pedicel and just before apical sulcus. Sensilla small, brown and inconspicuous. Proboscis black, hairless, about as long as mesonotum; palps short but strongly clavate, blackish with pale hairs, the longest about as long as the palps. Thorax. Mesonotum and scutellum shining black almost devoid of dusting except in recess above the wing bases. Cuticle smooth and shiny, hair insertions fairly conspicuous, on disc separated by their diameter or a little more. Bare paramedian lines extending back to about the mid point of the mesonotum, each a little narrower than the midline which has 5–6 irregular lines of hairs, uniform width throughout its length. Hind part of mesonotum slightly rougher textured close to scutellum, scutellum usually with noticeable transverse groves. Pleurae black with a thin covering of grey or brown dust except anepisternum and lower part of katepisternum which are shining or subshining black. Mesonotum and scutellum covered with long pale yellow to almost golden hair, that on the disc of the mesonotum anteriorly is as long or longer than width of frons, the majority of hairs overlapping their neighbours by most of the length of a hair. In many individuals the hind part of the mesonotum adjacent to the scutellum with much shorter hairs. Posterior half of anepisternum and pronotum covered with equally long pale yellow. Sometimes a few fine pale hairs on the middle of the katepisternum. Wing. Wing membrane conspicuously brownish infuscated anteriorly and basally, fading to grey-brown posteriorly and apically, the veins dark brown, base of costa and vein R blackish. Anal lobe well developed with smoothly curved posterior margin, as broad as anal cell, r-m close to middle of discal cell. Haltere. Yellow, becoming slightly brown at base of stem. Legs. Entirely black, the coxae thinly grey-brown dusted with long pale yellow hairs on outer surface; femora shining, undusted with the longest pale yellow ventral hairs decidedly longer than the greatest depth of a femur, tibia and tarsi with covering of minute dark setulae, the tibia also with longer erect yellow-brown hairs on basal half. Abdomen. Undusted black, often with faint bronzy or bluish reflections, dulled by closely packed punctures that are joined by transverse furrows, the disc of the tergites covered with pale yellow recumbent hairs significantly shorter than those on mesonotum. Laterally and on the down-curved margins the tergites are clothed with relatively longer, more erect yellowish hairs. Sternites grey dusted, also with similar long, pale yellowish hairs along their posterior halves. Genitalia. Prominent and conspicuous but smaller than in related species, shining black the gonocoxite covered in long, yellowish hairs similar to those on the lateral margins of the tergites, hairs on epandrium shorter but still quite long. In dried specimens the apex of the epandrium and lateral lobes of the gonocoxites usually dark like the rest. The characteristic shape of the gonostyli can often be seen, the curved basal spur being particularly distinctive.

Female. As male except as follows: wider frons and less clearly brown infuscation to wings in some individuals. Apical sternite longer than wide, apicomedially with a prominent blunt projection coverer in grey dust. Furca with tip pigmented, bluntly pointed or narrowly rounded, arms very short and almost straight.

Discussion. When Becker (1906b) did the first revision of the Usiini, he had at his disposal the Macquart types from the Paris Natural History Museum, but appears not to have seen the Fabrician types of U. atrata held in Copenhagen. He thanks Hansen and Lundbeck of Copenhagen for “valuable notes”, but does not list Copenhagen as contributing specimens. It would seem that either these notes were inadequate or he misinterpreted them. Perhaps because he had Macquart’s U. claripennis available for study he used this name for the North African species already named U. atrata by Fabricius, applying the Fabrician name to a rather different European species later described by Strobl as U. pubera . It would appear that all subsequent workers simply accepted Becker’s interpretation, continuing to propound his error.

The two Fabrician types still exist, one now in poor condition, the other, designated the lectotype, in remarkable preservation after 215 years. The lectotype is very readily identified with the common Moroccan species that previous authors have referred to U. claripennis Macquart , and is quite different to the European species which must now be called U. pubera Strobl.

Distribution. Northern Algeria, Morocco and northern Tunisia. A very common species in Morocco, occurring across most of the country, extending east through Algeria to northern Tunisia where only a couple of specimen have been seen.