Fannia xiaoi Fan 2000

Fannia xiaoi Fan, 2000

Fannia xiaoi Fan, 2000: 345.

Fannia xiaoi Fan: Wang & Xue, 2002: 58; Su & Wang, 2004: 112.

Description: Male: Body length 5.0 mm. Eye with sparse and short hairs, facets slightly enlarged on anterior margin in upper part; postocular setae fine and long on vertex; occipital setae short in one row; fronto-orbital plate and parafacial with greyish pruinosity; the median part of frons as wide as the distance between two posterior ocelli, frontal vitta black, about as wide as fronto-orbital plate, frontal setae 12 or 13, situated in the lower 4/5 of frons, upper orbital setae absent; parafacial bare, about as wide as antennal first flagellomere in median part; antenna black, first flagellomere 1.5X longer than wide, arista bare, distinctly swollen in basal 2/ 5; epistoma not projecting beyond vibrissal angle, vibrissal angle behind frontal angle in profile; gena and genal dilation with black hairs, upper margin of gena without upcurved setae; prementum slightly shining, with light grayish-yellow pruinosity, its length 3.0X longer than its width, palpus black, claviform, longer than prementum. Thorax black in ground colour, notum with gray pruinosity, without stripes; presutural acr triserial, hair-like, only prescutellar pairs slightly stout, the distance between acr rows narrower than the distance between acr row and dc row, dc 2+3, ia 0+2, pra 1, shorter than the length of posterior notopleural seta, notopleuron without seta; proepisternal setae 2, proepimeral seta 1, adjacent part with 8–10 fine hairs; basisternum, proepisternum, anepimeron, meron and katepimeron bare; katepisternal setae 0:1, katepisternum without ventral spines; spiracles dark brown; calypters brown, the lower one distinctly projecting beyond the upper one. Wing hyaline, wing-base yellowish-brown, veins brown, tegula black, basicosta brown, costal spine inconspicuous; vein Sc not curved bow-like; node of Rs bare on ventral and dorsal surfaces; veins R4+5 and M parallel to each other distally; vein R4+5 straight; crossveins without obvious cloud; haltere dark brown. Legs entirely black, fore tibia without ad and median p, fore first tarsomere with dense hairs on ventral surface; mid coxa without any hooked spines or spine-like setae on lower and outer margins, mid femur distinctly slender in distal 1/4, with 1 truncate ventral spine in basal part, av and pv rows long and stout in basal part, becoming gradually denser and shorter towards apex, av row comb-like in distal 1/4, pv row biserial in median part, p and pd rows absent, mid tibia slightly swollen in distal 3/5, with 1 or 2 short ad, 2 pd in distal half and dense slender hairs on ventral surface, the longest one about 1/2 of mid tibia width, its apex with 7 setae in one line from posterdorsal to ventral surfaces, mid first tarsomere slightly curved, without basal tooth-like spines on ventral surface, with 8 or 9 ad, the longest one about as long as 2/3 of first tarsomere; hind coxa bare on posterior surface, hind femur curved, swollen in distal 2/5 with 1 long av row, the longest one situated in submedian part, about 3/4 of tibial length, among which 6 or 7 long av curved in apex, 5 pv in distal 1/3, hind tibia with 1 av, 1 ad and 1 apical d, the longest one about 2/5 of tibial length, 1 or 2 seta rows in posterior and posteroventral surfaces. Abdomen long, depressed and flattened, with light grayish pruinosity; syntergite 1+2 to tergite 4 each with 1 median triangular vitta; sternite 1 with dense and fine hairs.

Specimens examined: Holotype male, China: Inner Mongolia: Hulun Buir, 28.v.1960, Coll. G.R. Xiao; 1 male, China: Heilongjiang: Guyuan, 1.vi.1980, Coll. C.Y. Cui.

Remarks: Fannia xiaoi can be easily distinguished from other Fannia by hind femur distally swollen and bearing a cluster of long setae, and mid first tarsomere with slender ad row. Fan (2000) originally assigned this species to the F. metallipennis -group. When we re-examined the holotype of F. xiaoi, its morphological characters and especially the male genitalic structures showed that this species should be transferred to this subgroup.

Distribution: China (Inner Mongolia, Heilongjiang).