Scatella stagnalis (Fallén), Fallen

Yang, Junhua Zhang Ding, 2005, Review of the subgenus Scatella Robineau­Desvoidy, 1830 from China (Diptera: Ephydridae), Zootaxa 931, pp. 1-11 : 6-8

Scatella stagnalis (Fallén)

( Figs. 20–29 )

Ephydra stagnalis Fallén, 1813: 248 . Type locality: Sweden.

Ephydra lacustris Meigen, 1830: 118 . Type locality: not given (? former Germany). Scatella buccata Robineau­Desvoidy, 1830: 801 . Type locality: not given (? France). Scatella tateyamana Matsumura, 1915: 225 . Type locality: not given (? Japan).

Diagnosis. Oral seta longer than width of antennal segment 3; scutellum with 2 pairs of sc, lateral sc short. Male T3 as long as T4, phallapodeme slender with 9–12 distinctly transverse stripes. Female S7 divided into two small sclerites.

Description. Male body length 2.5 mm, wing length 2.7 mm.

Head subshiny black, with thin rusty pollen; mesofrons nearly polished with reddish brown pollen. Setulae and setae on head black; 1outer vt as long as 1 inner vt; 1 pair of strong oc; 4 lateroclinate orb, the first and the third thin and short. Protruding face black with rusty pollen, with 2 long dorsoclinate facial setae on each side. Vibrissa very strong. Oral seta longer than width of antennal segment 3. Antenna black; arista short pubescent. Eye­to­cheek ratio, male 1: 0.26.

Thorax subshining black; mesonotum reddish brown microtomentose. Setulae and setae on thorax black. Pres dc short; no posts acr, a pair of strong acr just in front of suture; 2–3 humeral setae; anterior npl longer than posterior npl; 1 psa longer than sa; scutellum with 2 pairs of sc, lateral sc short; mesopleuron with 1 long seta; sternopleuron with 1 strong seta on upper portion. Legs subshiny black with grey pollen; tarsi brown. Setulae and setae on leg black. Fore femur with row of pv as long as width of fore femur. Wing brown with five faint hyaline spots, spots located cell R4+5 near tip of wing oval, Spots located cell R2+3 square; veins near spots not bent; first costal section moderately stout in male. Halter yellowish.

Abdomen subshining black with rusty pollen.

Male genitalia ( Figs. 21–27 ). Male T3 as long as T4; phallapodeme slender with 9–12 distinctly transverse stripes.

Female. Body length 2.6 mm, wing length 2.8 mm. Female genitalia ( Figs. 28–29 ). S7 divided into two small sclerites; ventral receptacle large, tube­like, about 3.3 times as long as wide.

Specimens examined. 1 male, Tibet: Mangkang, 16. 0 6. 1976, leg. Xuezhong Zhang; 1 female, Tibet: Mangkang, 16. 0 6. 1976, leg. Xuezhong Zhang.

Distribution. China (Tibet). This species is distributed worldwide.

Remarks. This species was redescribed by Olafsson (1991) in details with figurations of the male genitalia.

Figures

FIGURES 20 – 29. Scatella stagnalis (Fallén). Male. 20. Wing; 21. epandrium, cerci and surstyli, posterior view; 22. epandrium, cerci and surstyli, lateral view; 23. aedeagus, anterior view; 24. aedeagus, lateral view; 25. gonite, anterior view; 26. gonite, lateral view; 27. phallapodeme, anterior view. 28. Female genitalia, ventral receptacle; 29. abdominal sternites and cerci.