Brachylinga mexicana Webb, 2006

Webb, Donald W. & Metz, Mark A., 2006, A Revision of the New World Genera Brachylinga Irwin and Lyneborg and Lysilinga Irwin and Lyneborg (Diptera: Therevidae: Therevinae) with the Description of a New Genus, Elcaribe Webb, Zootaxa 1288 (1288), pp. 1-241 : 85-87

Brachylinga mexicana Webb spec. nov.

( Figs. 15, 38, 61, 84, 107, 130, 153, 176, 196, 216)

Etymology

­ anus (Latin) = pertaining to, belonging to. This name is used as an adjective and refers to the fact that most of the specimens were collected in Mexico.

Diagnosis

Brachylinga mexicana is taxonomically associated with B. sericeifrons in possessing setae on the katepisternum; in having the halter knob dark brown; in having the foretibia dark reddish brown; in having the gonocoxite ( Fig. 38) lacking short, thick, dark reddish brown apicomedial macrosetae and the median margin without a broad, quadrate, glabrous projection. Brachylinga mexicana differs from B. sericeifrons in having the gonocoxite ( Fig. 38) with several apicomedial, dark reddish brown macrosetae and lacking an aggregation of anteromedial setae; the gonostylus ( Fig. 107) lacking fine short spines laterally; the distiphallus in lateral view ( Fig. 176) with the apical third directed ventrally; and tergite 8 ( Fig. 15) thick medially.

Description of holotype male (MEI 042575)

Body length 6.3 mm.

Head. Length 0.88 mm. Ommatidia smaller ventrally and laterally. Frons pruinescence silver, black dorsally; setae black. Antenna/head length 0.73; black, scape with pruinescence gray; scape length 0.24 mm, width 0.15 mm, length/width 1.6, scape/ pedicel length 3.0, scape/flagellum width 1.0, setae black intermixed with white setae; pedicel length 0.08 mm, length/width 0.8; flagellum length 0.32 mm, width 0.15 mm, length/width 2.1, flagellum/scape length 1.3. Parafacial pruinescence white. Maxillary palpus dark brown, pruinescence gray; length 0.46 mm, length/width 7.7; setae dark brown. Genal setae white. Occipital setae white. Postocular macrosetae dark reddish brown.

Thorax. Macrosetae dark reddish brown, 3 np, 2 sa, 1 pa, 1 dc, 2 sc. Mesonotum dull brownish gray; setae black intermixed with white setae. Pleuron and scutellum black, pruinescence gray; setae white on propleuron, anepisternum, katepisternum, metanepisternum, laterotergite, and scutellum. Wing. Membrane pale gray, veins brown; length 5.2 mm, length/width 2.9; pterostigma dark brown; cell m 3 open slightly. Halter dark brown. Legs. Coxa setae white, present on posterior surface of midcoxa; macrosetae dark reddish brown. Femora dark reddish brown, pruinescence gray; ventral setae white intermixed with black setae; av 2:0:3, pv 0:0:2. Tibiae dark reddish brown. Tarsi dark reddish brown.

Abdomen. Dark reddish brown, pruinescence white on tergites 1–2, dense on tergites 3–8; dorsal setae white, appressed; lateral setae white, erect. Terminalia (MEI 038642). Tergite 8 ( Fig. 15), median length thick (0.07 mm); setae dark yellow, absent medially on posterior margin (occasionally present). Sternite 8 ( Fig. 38) quadrate, sides rounded, posterior margin slightly emarginate. Epandrium ( Fig. 15), sides tapered apically; setae dark brown. Cercus ( Fig. 15), ending basal to apex of hypoproct. Hypoproct ( Fig. 15), posterior margin emarginate, ending distal to apex of cercus. Gonocoxite ventral view ( Fig. 38) slightly rounded laterally, medial margin straight, then tapering apically to short, blunt point; setae dark yellow, dark brown macrosetae along apicomedial margin; dorsal view ( Fig. 61), posteromedial lobe absent, gonocoxal bridge short; lateral view ( Fig. 84) rectangular, tapering apically to short broad point; ventral lobe ( Fig. 38) lacking ventral spines. Gonostylus ( Fig. 107), basodorsal lobe small, rounded; ventral margin curved, setae dark yellow, not directed apically in distinct tuft; fine, short spines absent laterally. Aedeagus with dorsal apodeme ( Fig. 130) quadrate, posterolateral margin rounded; ventral apodeme ( Fig. 153) tapered anteriorly, slightly expanded apically, not extending to anterior margin of dorsal apodeme; distiphallus dorsal view ( Fig. 130) tapered apically, lateral view ( Fig. 176) apical third curved ventrally at 90° angle, apicolateral spines absent; ejaculatory apodeme ( Fig. 130), anterior margin slightly emarginate.

Variation (n=10). Body length 5.3–7.8, 6.6 mm.

Thorax. Macrosetae 3 np, 2 sa, 1 pa, 0–2 dc, 2 sc. Legs. Anteroventral macrosetae 0–1:0:2–5, pv 0–1:0:2–5.

Female

Similar to male except for following.

Variation (n=10).

Body length 6.2–8.2, 7.0 mm.

Head. Frons dark brown, pruinescence brownish gray, ventral third silver with diffuse brownish black area dorsolaterally which broadens across frons when rotated; setae dark brown on dark brown area of frons. Antenna dark brown, scape with pruinescence gray; setae on scape pale brown, elongate. Parafacial pruinescence white. Maxillary palpus dark yellowish brown, pruinescence gray; setae white. Genal setae white. Occipital setae white.

Thorax. Macrosetae 3 np, 2 sa, 1 pa, 0–2 dc, 2 sc. Mesonotum dull brown; setae black intermixed with white setae. Pleuron and scutellum brown, pruinescence gray. Wing. Cell m 3 open widely. Legs. Anteroventral macrosetae 0–1:0:2–5, pv 0:0:2–4.

Abdomen. Dark reddish brown, glossy, pruinescence gray laterally on tergite 1, posterolaterally on tergites 2–3, and across posterior half of tergite 5; dorsal setae dark reddish brown, short with white setae across posterior margin of tergite 1 and posterolateral margin of tergites 2–3. Terminalia (MEI 042558). Furca ( Fig. 196) oval; length 0.38 mm, width 0.22 mm; anterolateral projection short. Common duct ( Fig. 196) shorter than furca. Spermathecal duct ( Fig. 196) diverging anteriorly.

Distribution

Brachylinga mexicana is known from northwestern Mexico and southern California ( Fig. 216).

Habitats and phenology

Brachylinga mexicana has been handnetted in sand canyons and collected from sandy dunes and on Yucca mohavensis Sarg. Adults have been collected from March to June.

Specimens examined

Type specimen. The holotype male of Brachylinga mexicana Webb (MEI 042575) is labeled "Mex. Baja Calif. N., 6 mi N San Borja, 24.III.70, E. M., J. L. Fisher" and is deposited in the CAS (Type No. 18115). PARATYPES: MEXICO. BAJA CALIFORNIA NORTE. 6.4 km N Bahia de los Angeles [28.973, ­113.511], 23.III.1970, E. M. Fisher, J. L. Fisher, 1♂ MEI 042574, 1♀ 042550 ( INHS) ; 56.4 km S El Progreso, Arroyo Caravina [29.47, ­115.183], 2.IV.1976, J. Doyen, 4♀ MEI 042547–8, 043562, 043597 ( EMEC) ; 16.1 km SE El Rosario [29.97, ­115.667], 31.III.1976, J. T. Doyen, 2♀ MEI 043543, 043548 ( EMEC) ; 20 km E El Rosario [30.073, ­115.6], 5–6.IV.1981, E. M. Fisher, J. T. Huber, J. LaSalle, 1 ♂ MEI 072379 ( CSCA) ; 61 km NW Punta Prieta [28.933, ­113.619], 10.IV.1977, E. M. Fisher, 1 ♂ MEI 042558 ( UCR) ; 4.8 km N San Felipe [31.032, ­ 114.817], 10 m, 25.III.1964, J. C. Ball, 1♀ MEI 042476 ( MEIC) ; 9.7 km S San Felipe [30.945, ­114.855], 14.IV.1965, D. Q. Cavagnaro, C. E. & E. S. Ross, V. L. Vesterby, 1♂ MEI 112257 ( CAS) ; 12.2 km S San Jicante [31.22, ­116.35], 23.V.1980, Brown, Faulkner, 1♀ MEI 039776 ( SDMC) ; 4.8 km SW San Quintin [30.519, ­115.953], 6.IV.1982, Brown, Faulkner, 1♀ MEI 039809 ( SDMC) ; 25.3 km N San Borja [29.08, ­113.78], 24.III.1970, E. M. Fisher, J. L. Fisher, 1♀ MEI 042546 ( UCR) ; 10 km N Punta Prieta [29.02, 114.161], 20.III.1986, R. R. Parmenter, 1♂ MEI 128867 ( INHS) ; 14.5 km S Loreto [25.894, ­ 111.366], 9.VI.1980, Brown, Faulkner, 1♀ MEI 039775 ( SDMC) . SONORA. Choya Bay [31.35, ­113.45], 27.III.1949, G. M. Bradt, 1♂ MEI 043511 ( AMNH) ; 11.3 km WSW Bahia San Carlos, vicinity Punta San Antonio [27.943, ­111.097], 10.IV.1968, E. M. Fisher, 1♂ MEI 106302 ( UCR) ; Puerto Peñasco [31.32, ­113.54], 21.III.1967, F. G. Andrews, 2♂ MEI 042555, 042561 ( MEIC) , sand canyon. UNITED STATES. CALIFORNIA. Riverside County: near Hemet, Bautista Canyon [33.698, ­116.852], 29.IV.1972, G. R. Ballmer, 1♀ MEI 076158 ( UCR) . San Bernardino County: Cottonwood Spring , 13.IV.1950, P. D. Hurd, 1♀ MEI 040891 ( EMEC) , 17.7 km SE Baker, on Kelbaker Road [35.222, ­115.885], 671 m, 19.IV.1969, W. Hunt, 1♂ MEI 042576 (ME IC), Yucca mohavensis ; Cadiz [34.52, ­115.512], 241 m, 3.IV.1981, N. J. Smith, 1♂ MEI 038642 ( EMEC) , sand dunes.