Schizella Bezzi, 1917

Kerr, Peter H., 2010, 2592, Zootaxa 2592, pp. 1-133 : 78-79

Genus Schizella Bezzi

Figs. 2, 18, 58, 80.

Schizella Bezzi 1917: 118 . Type species Schizella furcicornis Bezzi 1917 , by original designation.

Diagnosis. The monophyly of the species of Schizella is supported by the autapomorphic form of the male first flagellomere, which is expanded conspicuously into a bifurcate process.

Schizella species are delicate, small to mid-sized (3.7–6.3 mm) flies, with long, thin legs; thorax brown to orange-brown with blue-, purplish-, or golden-colored setae. Wings are hyaline, without markings; male holoptic, eyes separated in female; in female, arista produced ventrally; first flagellomere subcircular, laterally compressed; in male, first flagellomere enlarged and forked; arista short; mandibles absent; laterotergite setose; M 3 present; tibial spur formula 0:2:1; hind tibia with short macrochaetae; tergite 9 without ventrolateral arms; female spermathecal ducts with accessory glands. The males of Schizella are unlikely to be confused with any other brachyceran genus, on account of their highly modified antenna. Females of Schizella are separated from most Chrysopilus species by having the arista produced ventrally from the first flagellomere.

Description. Head. Clypeus bulbous. Scape approximately same size as pedicel. First flagellomere of female antenna enlarged basally, bearing long stylus, which originates anteroventrally. In male, first flagellomere enlarged and forked; arista short. Eyes dichoptic in both sexes, inconspicuously setulose; ocelli evenly spaced, of equal size. Labella with pseudotracheae, longer than palpus. Theca short and stout. Palpus one-segmented. Mandibles absent.

Thorax. Mesonotum without vittae. Dorsocentral bristles absent; all dorsal setae of equal length. Anepisternum setulose on dorsal margin only. Laterotergite setose. Postspiracular scale absent. Metallic- or scale-like thoracic setae, often with structural color present. Postspiracular sclerite bare. Proscutellum absent. Subscutellum not enlarged nor lengthened; inconspicuous. Wing hyaline, without markings; pterostigma present or absent. Lower calypter reduced. Upper calypter well developed, but margin with curvature narrow, width more than twice length. Costa extends past wing tip (to at least R 5). Humeral crossvein well developed. Sc-r crossvein absent. Dorsal side of R 1 setulose, ventral side bare. All other wing veins without setulae. R 1 and R 2+3 close together at wing margin. R 2+3 sinuous, apical third ultimately bends anteriorly slightly, toward leading edge of wing margin, length of R 2+3 about as long as R 5 or longer. Base of R 4 –R 5 fork proximal or directly above distal end of cell dm. R 4 at base strongly curved or angled, often with short proximal offshoot at point of curvature near R 5, nearly straight apically. R 4 and R 5 encompass wing tip, or R 5 anterior to wing tip. R 5 clearly longer than R 4+5 (r-m to R 4 origin). R-m crossvein at proximal side of central one-third of discal cell (or more centrally). M 3 present. Origin of CuA 1 at cell bm. Cell m 3 parallel-sided at margin. CuA 2 greater than 2/ 3 length of posterior vein of cell bm. Alula full, rounded, with broad curvature. Anal lobe well developed. Cell cu p open. Halter knob approximately 1/2 length of stem. Tibial spur formula 0:2:1. Hind coxal tubercle absent. Hind tibial macrochaetae present, short. Postmetacoxal bridge absent.

Abdomen. Abdominal segments evenly tapered. In female, last 3 abdominal segments telescoping; tergite 7 much longer than wide; intersegmental membrane between segments 7 and 8 especially long; sternite 8 length elongated; more than twice as long as wide. Male terminalia with epandrium simple, not containing hypandrium ventrally. Epandrium wider than long, strongly notched anteriorly. Tergite 10 absent. Hypoproct tomentose, without setae. Cerci widely displaced from one another, separation distance greater than three quarters width of cercus; held at angle in relation to rest of abdomen; in posterior view cupped, forming circular outline medially. Hypandrium fused entirely to gonocoxites. Gonocoxite with sinuous dorsal ridge, leading to gonocoxal apodeme. Gonocoxal apodemes short or long enough to reach anterior margin of hypandrium. Sperm sac bulbous, without paired swellings ventrally. Lateral ejaculatory processes present, not part of sperm sac posteriorly. Ejaculatory apodeme moderately long, reaching to at least anterior margin of hypandrium. Ejaculatory apodeme rod-shaped (upside-down v-shaped in profile). Aedeagal tines absent. Endoaedeagal process absent. Female terminalia with three spermathecae, clubbed, moderately to well sclerotized. Spermathecal ducts longer than five times length of sternite 9, but not so long as to be difficult to measure, not inflated at base of spermathecae. Spermathecal duct accessory glands arise at approximately the distal third of the spermathecal ducts. Ejection apparatus of spermathecal ducts lightly sclerotized, not thickened, without surface furrows. Common spermathecal duct thinner than individual ducts, about as long as longest diameter of genital chamber. Genital chamber elliptical, elongate, occupying most of sternite 9 area. Accessory gland posterior to genital chamber inconspicuous, easily overlooked even after staining. Sternite 9 anterior end pointed, with broad extensions posteriorly that are held in horizontal plane. Tergite 10 present. Sternite 10 split into two sclerites. Cercus two-segmented. First segment of cercus not elongate, without ventral process. Ventral lobes of first segment of cercus curve ventrally towards one another to form ring, visible in posterior perspective. Basal cercal segment adjacent dorsally. Second cercal segment not elongated, without apical sensory pits.

Larva. Unknown.

Biology. Unknown. Members of this genus are found exclusively in the Philippines.

Literature. Nagatomi (1982a) gives a cursory treatment of the genus. Kerr (2003) provides a key to all species.