Megalestes discus, Wilson, 2004

K. D. P. Wilson, 2004, New Odonata from South-China, Odonatologica 33 (4), pp. 423-432 : 426-427

MEGALESTES DISCUS SP.NOV.

Figures 4-8

Material. — Holotype ♂: Mangshan (nearBabaoshan), Shikengkong,S Hunan, China, 26-VI-2000, K.D.P. Wilson leg. — Paratype: 1 ♂, ditto, 26-VI-2000. Holotype will be deposited at Tai Lung Experimental Station , Agriculture , Fisheries and Conservation Department , Lin Tong Mei , Sheung Shui, Hong Kong SAR, China.

Etymology. — Named after the disc-like structure at the base of the superior appendages.

Description. — Small-sized Megalestes with pale disc-like structures located at base of male superior appendages.

MALE. — Labium pale whitish yellow. Labrum shiny metallic green with lateral distal borders pale yellow. Base of mandibles pale yellow. Anteclypeus blackish spotted with pale yellow. Postclypeus, firms, top of head and rear of head shiny metallic green. Antennae black with small pale yellow spot at base. Ocelli pale yellow. The frontal head is illustrated in Figure 4 . Prothorax blackish metallic green with pale yellow frontal lobe, rear lobes and lateral margin. Dorsum of synthorax and mesepimeron shiny, dark metallic green with black humeral suture ( Fig. 5 ). Metepisternum shiny, dark metallic green with pale yellow stripe which is broad anteriorly and narrows towards posterior. The pale yellow stripe is finely bordered with black margin. Metepimeron and metaposternum pale yellow. Coxae pale yellow. Legs pale brown outer faces and dark brown inner, ventral faces. Wings hyaline with dark brown pterostigma, covering three cells, braced at anterior margin. First two segments blackish above with metallic green reflection and pale yellow below. Segments 3-5 bronzy brown with faint metallic green reflection. Segments 6-8 dark brown with metallic green reflection. Segments 9-10 blackish brown with faint metallic green reflection covered in whitish pruinescence prior to preservation. Superior appendages blackish with pale disk-like structure at dorsal base ( Figs 7-8 ). Quadrate, peg-like projection, bifurcated at tip, downward and posterior pointing, originating from inside face of the superior appendage below disk-like structure. Inferior appendages with stout central posterior directed projection beset at tip with long upwardly curved orange brown hairs. Penile organ is illustrated in Figure 6.

Measurements (mm). - abd. + app.49.0-50.0,hw 32.0-35.0.

differential DIAGNOSIS. — There are five Megalestes species known from China. These comprise M. chengi Chao, 1947 from Fujian, M. distans Needham, 1930 from Guangxi, Jiangxi and Sichuan M. heros Needham, 1930 from Fujian, Zhejiang and possibly Sichuan, M. maai Chen, 1947 from Taiwan, M. micans Needham, 1930 from Sichuan, Yunnan and Assam and M. riccii Navas, 1935 from Jiangxi. M. discus is the only Chinese member of the genus to possess superior appendages with basal disc-like structures. It is closely related to M. lieftincki LAHIRI (1979), which is the only other Megalestes known to possess superior appendages with distinctive basal expansions. The inferior appendages of lieftincki have an upward pointing spine (absent in discus ) in addition to the curved tip.

Figures

Figs 1-8. [1-3] Rhinocypha chaoi sp. n., ♂: (1) hindwing; (2) tho­ rax, lateral; (3) abdomen, lateral; [4-8] Megalestes discus sp. n„ ♂J: (4) head, frontal: (5) thorax, lateral; (6) penile organ, ventral; (7) caudal appendages, dorsal; (8) caudal appendages, lateral.