Ceromya glaucescens Tachi & Shima

Tachi, Takuji, 2017, Description of the female of Ceromya glaucescens Tachi & Shima (Diptera: Tachinidae) and discovery of unusual sexual dimorphism in this species, Zootaxa 4237 (3), pp. 583-586 : 584

Ceromya glaucescens Tachi & Shima

( Figs 1–6 )

Ceromya glaucescens Tachi & Shima, 2000: 136 . Type locality: Sasagamine, Myôkôkôgen-cho, Niigata Prefecture, Japan.

Material examined. Holotype ♂, Honshu, Niigata, Myôkôkôgen-cho , Sasagamine 23.vi.1996, T. Tachi leg. ( BLKU) ; 1 ♂, Kyushu, Fukuoka Prefecture, Fukuoka City, Mt. Kusenbu , 17.iv.2015, H. Shima leg. ( BLKU) ; 1 ♀, same data as previous except 2.v.2015 ( BLKU) ; 1 ♀, Kagoshima Prefecture, Mt. Shibi , 12.v.2013, T. Tachi leg. ( BLKU) .

Diagnosis. Three presutural and four postsutural dorsocentral setae; lower katepisternal seta subequal in length to anterior katepisternal seta; veins R1 and CuA1 bare; vein R4+5 setulose dorsally nearly to level of crossvein dm-cu.

Description of female. Head. Face, fronto-orbital plate and parafacial light grey, with whitish pruinosity; frontal vitta orange to reddish-brown; gena orange at genal groove; postgena and occiput grey, with yellowish-grey pruinosity. Pedicel, scape and upper 1/3 of first flagellomere orange, lower 2/3 of first flagellomere reddish-brown to black; arista dark brown; palpus orange. Vertex approximately 0.38 of head width; parafacial narrower than length of second aristomere at mid height; gena 0.23–0.27 of eye height; 5 frontal setae; anterior reclinate orbital seta situated posterior to middle of fronto-orbital plate; upper occiput and postgena with black setae only. First flagellomere approximately 4 times as long as pedicel; second aristomere 2.0–2.5 times as long as wide; third aristomere thickened on basal half; prementum normal, approximately 3 times as long as wide.

Thorax. Dorsum and pleura light grey, with yellow pruinosity; scutellum yellow on apical 2/3, with whitish-grey pruinosity, light grey on basal 1/3. Three presutural and four postsutural dorsocentral setae; lower katepisternal seta subequal in length to anterior katepisternal seta. Wing. Hyaline; tegula reddish-brown; basicosta orange. Relative lengths of costal sectors 2, 3 and 4 approximately as 2:7.5:3; last section of vein CuA1 0.26–0.30 times as long as second-last section and subequal in length to crossvein r-m; vein R1 bare; vein R4+5 setulose dorsally nearly to level of crossvein dmcu, with a long basal setula ventrally; vein CuA1 bare. Legs. Orange in ground colour. Outer surface of fore femur dark grey on basal 4/5, inner and outer surfaces orange on apical 1/5. Fore tibia with a long preapical anterodorsal seta, approximately 0.7 times as long as preapical dorsal seta, and with 4–5 anterodorsal setae; mid tibia with 2 anterodorsal, 2 posterodorsal and 1 ventral setae; hind tibia with 4–5 anterodorsal and 4–5 posterodorsal setae of unequal length, and 3– 4 ventral setae.

Abdomen. Grey in ground colour; anterior 2/3 of syntergite 1+2 with thin, white pruinosity; anterior 3/4 of tergites 3 and 4 and whole of tergite 5 with dense, bluish-white pruinosity. Syntergite 1+2 with a pair of lateral marginal setae; tergites 3 and 4 each with 1–2 pairs of lateral discal setae.

Body length. 4.5‒5.0 mm.

Remarks. This species shows sexual dimorphism in the thoracic ground colour and leg chaetotaxy, as outlined above. However, it can be distinguished from other species of Ceromya by the following combination of features: three presutural and four postsutural dorsocentral setae; lower katepisternal seta subequal in length to anterior katepisternal seta; veins R1 and CuA1 bare; vein R4+5 setulose dorsally nearly to level of crossvein dm-cu.

Figures

FIGURES 1 – 6. Ceromya glaucescens Tachi & Shima. 1 – 2, 5. Female (Kagoshima Prefecture, Kyushu, Japan). 3 – 4, 6. Holotype male (Niigata Prefecture, Honshu, Japan). 1, 3. Fore tibia in dorsal view. 2, 4. Mid tibia in dorsal view. 3. Fore tibia in dorsal view. 4. Mid tibia in dorsal view. 5 – 6. Habitus in left lateral view. 6. Habitus in left lateral view. The arrows on Figs 1, 3 and 2, 4 highlight the preapical dorsal seta on the fore tibia and the anterodorsal setae on the mid tibia, respectively. Scale bars: 0.5 mm for Figs 1 – 4, 2 mm for Figs 5 – 6.