Nothybidae Aczél, 1955

Lonsdale, Owen, 2020, Family groups of Diopsoidea and Nerioidea (Diptera: Schizophora) - Definition, history and relationships, Zootaxa 4735 (1), pp. 1-177 : 25-26

Nothybidae Aczél, 1955

( Figs 50–64 , 399–400 )

Type genus: Nothybus Rondani 1875: 439 , by Aczél (1955c: 2). Type species of genus: Nothybus longithorax Rondani, 1875: 439 [= N. longicollis Walker, 1856: 135 ] by monotypy.

The small family Nothybidae contains the single genus Nothybus , which occurs throughout much of the Oriental Region including India, as well as Papua New Guinea and Nepal. Mention of specimens from the Solomon Islands in Evenhuis (1989f) cannot be verified. Nothybidae was recently revised by Lonsdale & Marshall (2016), who described and imaged the larva, and recognized and figured 11 species, three of which were newly described.A twelfth species described by Galinskaya & Shatalkin (2017) on the basis of a single female appears to be conspecific with N. longicollis .

Biology. Little is known of the biology of Nothybus . D.K. McAlpine (1974) noted hovering in a Malaysian male of N. lineifer Enderlein (as N. decorus Meijere ) that when captured, hovered over the author’s arm and “struck it rapidly two or three times with the abdomen as if attempting to sting or lay eggs”, and when at rest, held its wings slightly raised over the abdomen with the anal lobes touching and the costal margin slightly raised. When at rest, this male waved its fore legs “reminiscent of the family Micropezidae ”. Similar behaviour in Chinese and Vietnam- ese specimens was noted in Paiero & Marshall (2014) and Lonsdale & Marshall (2016), with specimens waving forelegs in the manner of incheumonid antennae, and patrolling leaf surfaces in patches of filtered sunlight along forest streams and paths. Paiero & Marshall (2014) discussed some behaviour of N. sumatranus Enderlein , where both sexes were observed standing or slowly walking on leaf surfaces, or slowly flying between leaves; courtship behaviour was described and photographed, wherein the male deposited oral fluids on the leaf surface as part of a nuptial gift, which is otherwise unknown among diopsoids. Similar behaviour was also observed for N. longicollis ( Lonsdale & Marshall, 2016) . Specimens have been collected in numerous forest types, often near water ( McAlpine, 1974; Lonsdale & Marshall, 2016).

Species are likely viviparous, with McAlpine (1989) recovering a larva from the enlarged oviduct of a N. longicollis female, and Meier et al. (1999) noting simultaneous facultative viviparity in N. kempi (Brunetti) , with mature eggs in the ovaries. A single larva was recovered by Lonsdale & Marshall (2016) from the abdomen of a N. longicollis female.

Immature stages. The larva of N. longicollis was photographed and described by Lonsdale & Marshall (2016).

Adult Diagnosis. Relatively large-bodied, long-legged, slender and elongate, with anterior portion of thorax moderately to strongly produced, far removed from fore coxae; body length 5.5–15.0mm ( Figs 49–55 ). Subscutellum large and subconical, reaching or exceeding apex of scutellum. Colour often orange to brown or partly black with abdomen darker, and with variable striping of pigment or iridescence on head and thorax; head with three dark velvety patches. First flagellomere slightly to distinctly angled, narrow, twice as long as wide; pedicel with dorsal seam. Precoxal bridge present, postmetacoxal bridge absent. Vibrissa, ocellar, postocellar, postpronotal, anterior notopleural and katepisternal setae absent. Two strong pairs of scutellar setae; 1 notopleural, 1 dorsocentral and 1 anepisternal. Wing with alula and anal lobe nearly absent ( Figs 399–400 ); radial and medial veins divergent; patterning often distinct and elaborate; cell cua and bm very short, with cell bm open anterodistally; cell br open; upper calypter margin pubescent; costa unbroken; sc complete. Female tergite and sternite 7 separate, not forming oviscape.

Adult Definition [from Lonsdale & Marshall (2016)]. Body length 5.5–15.0mm.

Colour: ( Figs 49–55 ) Setae mostly or entirely black. Usually yellowish-orange in base colour with mottling or ill-defined stripes, abdomen often darker; sometimes dark brown with smaller orange patches. Most of thorax and abdomen with light greyish to thicker black pruinosity; at least tergite 5 with black velvety patch. First flagellomere usually black apically, face usually with dark brown to black spot often flanked or surrounded by silvery tomentosity. Frons with three black velvety patches including one comma-shaped pair anterolaterally and one rounded/subquadrate patch behind ocelli. Thorax always with purplish-white pruinose iridescent stripes that are most prominent on postpronotum. Apices of femora, tibiae and tarsi usually dark; fore tarsus white, at least at base. Wing often lightly infuscated past dm-m, sometimes with discrete infuscated bands around veins, and often with darker pigment marginally; usually with transverse brown band extending from M 4 to costa at level of dm-m, past which is clouded region often enclosing two or three clear and strongly iridescent spots in cells r 2+3, r 4+5 and m 1. Halter white to yellow, base usually partially brown, knob sometimes faintly brownish.

Chaetotaxy: 1 inner vertical; 1 outer vertical; 2 reclinate fronto-orbitals (anterior slightly inset); 0 ocellars; 0 postocellars; vibrissa absent. 0 presutural intra-alars; 0 postpronotals; 1 notopleural (anterior seta absent); 1 posterior supra-alar; 1 postalar; 0 posterior intra-alars; 1 dorsocentral; 0 acrostichals; 1 lateral scutellar, 1 apical scutellar; 0 proepisternals; 1 anepisternal; 0 katepisternals. Weak lateral row of postocular setae. Mid coxa with strong lateral seta. Mid tibia with 1 strong ventroapical seta. Pedicel with one large dorsal and several enlarged ventral setae; dorsal half of face, parafacial and anterolateral region of frons minutely setulose ( Fig. 49 ); prementum one pair of short and long setae. Thoracic setulae in relatively consistent, characteristic pattern of rows ( Fig. 51 ). Tibiae and tarsi with setulae in rows with dense ventrobasal patch on basitarsomeres.

Head. Suborbicular, ocelli apparently near midpoint of head. Antenna angled with pedicel cap-like and with dorsal seam, arista bipectinate; first flagellomere slightly longer than wide. Face well sclerotized, convex; often with dark brown to dark yellow protrusion/tubercle ventromedially. Gena and postgena very narrow. Clypeus large, produced; labium widest distally; palpus narrow. Head with broad post-ocellar concavity and bulge above foramen.

Thorax. Extended anteriorly, displaced from base of fore coxa (pronounced in N. longicollis ); postpronotum elongate. Posterolateral corner of notopleuron with small tubercle at base of seta. Scutellum relatively long, flat dorsally and laterally. Subscutellum conical, larger than scutellum ( Figs 50–51, 53 ). Posterodorsal margin of katepisternum abruptly recessed. Proepisternum extending into lobed plate anteriorly. Katepisternum and meron partially fused. Greater ampulla absent. Coxopleural streak sometimes visible. Precoxal bridge present, very large and broad, fused to teardrop-shaped prosternum; postmetacoxal bridge absent. Spiracles broadly ovate, fringed with short hairs.

Wing. ( Figs 399–400 ) Length 5.0– 10.4mm. Alula and anal lobe vestigial. Costa unbroken. Vein sc complete. CuA+CuP reaching wing margin when present. Cell cu a and bm short. Cell br open. Cell bm open anterodistally. Basal cells and cell cu a without microtrichia. Radial and medial veins divergent. M 4 reaching wing margin. CuA slightly curved. Upper calypter linear, pubescent; lower calypter vestigial.

Legs. Long and slender; tarsus elongate, similar in length to tibia. Hind basitarsus with slight basal swelling, similar to Tanypezidae .

Abdomen. Relatively stout, subcylindrical, slightly constricted at base and gradually tapeed apically. Pregenitalic sternites long and narrow, except sternite 1 wider than long, and sternite 6 relatively short. Spiracles 1–6 in membrane, male 6th spiracles associated with weakly sclerotized margin of tergite 6; 7th spiracle sometimes absent.

Male genitalia. ( Figs 56–61 ) Sternite 7 membranous, very short. Sternite 8 dorsal, tapered laterally, symmetrical. Cercus finger-like or relatively broad, often flat or slightly raised, subconical in N. longicollis . Surstylus long and slender to small and rounded; usually at least partially fused to epandrium (free in N. longicollis ). Subepandrial sclerite with curved medial plate extending ventrally to fuse to inner surface of surstylus. Hypandrium with broad, densely setose lateral plates, usually broadly connected medially to phallapodeme (separate in N. longicollis ). Pregonite well-developed, setose, pointed, textured; this structure is here interpreted as the pregonite because of its external articulation with the hypandrium and chaetotaxy, although its position relative to the base of the phallapodeme suggests that it could instead be the postgonite, which is currently interpreted as absent. Basiphallus subcylindrical with ring-like base, fused to distiphallus, extending posteriorly as reticulate and ill-defined epiphallus. Distiphallus long, flat and ribbon-like with one pair of dark bands extending at least to midpoint; apex often with one pair of clear tubules. Ejaculatory apodeme with clear blade; stalk well-developed with minute cylindrical perforations and asymmetrical base usually enclosing narrow fossa; sperm sac membranous.

Female genitalia. ( Figs 62–64 ) T7 and S7 separate. Female terminal segments relatively short, wider than long; T8 sometimes longitudinally divided basally; S8 sometimes entirely divided; T10 and S10 small, subtriangular. Two small black spherical spermathecae on separate long, unpigmented, distally narrowed ducts that arise on short common duct or process of bursa copulatrix. Ventral receptacle with transversely wrinkled stem expanding into bent, sometimes pigmented apical lobe with small membranous sac emerging subapically.

Figures

FIGURES 47–55. Fig. 47: Psila hennigi (Thompson & Pont), ex lab culture. Fig. 48: Chyliza sp., Ontario, Canada. Figs 49–53: Nothybus longicollis (Walker) (Nothybidae); 49: head, anterior; 50: lateral; 51: dorsal; 52: ventral; 53: holotype male. Fig. 54: Nothybus sumatranus Enderlein. Fig. 55: Nothybus absens Lonsdale & Marshall, holotype, male.

FIGURES 56–61. Nothybus triguttatus Bezzi (Nothybidae), male abdomen; 56: segment 6 to genitalia, lateral; 57: external genitalia, posterior; 58: same, anterior; 59: segment 6 to sternite 8, ventral; 60: internal genitalia, ventral; 61: same, left lateral.

FIGURES 62–70. Figs 62–64: Nothybus biguttatus Wulp (Nothybidae), female abdomen; 62: segment 7 to cercus, ventral; 63: same, dorsal; 64: internal genitalia. Figs 65–66: Somatia aestiva (Fabricius), female abdomen; 65: segment 7 to cerci; 66: internal genitalia. Figs 67–70: Gobrya sp., female abdomen; 67: segment 6 to cerci, dorsal; 68: same, right lateral; 69: same, ventral; 70: spermathecae.

FIGURES 395–402. Wings; 395: Belobackenbardia cornicula Shatalkin (Psilidae), female paratype; 396: Chyliza notata Loew (Psilidae); 397: Psila hennigi (Thompson & Pont) (Psilidae); 398: Loxocera cylindrica Say (Psilidae); 399: Nothybus longicollis (Walker) (Nothybidae); 400: N. biguttatus Wulp; 401: Somatia aestiva (Fabricius) (Somatiidae); 402: Gobrya sp. (Gobryidae).