Oligoaeschna mutata, Lieftinck, 1940

M. A. Lieftinck, 1940, Descriptions and records of South-East Asiatic Odonata (II), Treubia 17 (4), pp. 337-392 : 221-383

Oligoaeschna mutata . sp. n. ( fig. 18 ).

Material studied: - 1 ♂ (ad., holotype), E. Borneo, Samarinda, Jan. 1939, native collector, M. E. WALSH ded .; 2 ♀ (ad.), E. Borneo, N. Koetai, Sangkoelirang distr., Kariorang , Jan. 2 & Febr. 21, 1937, J. W Quarles DE Quarles leg. All in the Buitenzorg Museum .

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Male (ad.), - Head coloured similarly to platyura . but dorsal surface of frons with two isolated, transverse, olive-green streaks on a reddish-brown background; or, in other words, a blackish-brown T-shaped mark on the upper surface With its stem broad, changing to reddish-brown basally and attached to a broad basal band of the same colour. Vertex and occipital triangle black. Rear of the head tawny.

Synthorax brown, blackish-brown above. Dorsum marked with green as in platyura and amata . On the sides are two broad, diffuse, green epimeral bands whose antero-dorsal limits are indistinct owing to postmortem decomposition. Apparently no metepisternal coloured spots present. lnfraepisternites and under surfaces brown.

Coxae brown; trochanters and femora red-brown with the apices of the latter black; tibiae darker brown, bases and apices obscured; tarsi Blackish

Wings tinted with greyish amber; anal area of hinder pair almost hyaline, wing-tips slightly smoky. Pterostigma braced. 2.0 mm in length (fore wing), 1.9 (hind wing), tawny between black nervures.

Venation open, very similar to modiglianii ; a single row of cells between M4-Mspl. Triangles 3-celled; supratriangles with a single cross-nerve in all wings. Anal angle and membranula shaped exactly as in amata .

Nodal index 8.16.15.9/9.11.11.10 Abdomen constricted on segment 3 (1.1 mm), not appreciably spindle-shaped beyond, acquiring its maximum width (2.3 mm) towards the middle of segm. 5, from where the abdomen diminishes but slightly and very gradually till the end. Terminal segments slightly depressed.

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Black, dark brown on the sides of 1 and 2, marked with blue as follows: — A roundish spot on sides of segment 1; 2 with a triangular spot above the auricles, a minute triangular basal mid-dorsal spot, a pair of trapezoidal transverse dorsal spots at the jugal suture and a pair of closely approximated apical lunules of the same size as the jugal spots; segm. 3 - 6 each with similar, though smaller, jugal and apical spots, the former progressively smaller from before backwards and vestigial on 6, the latter in the form of narrow, transverse, dorso-lateral rings, finely constricted in the middle on 3 - 5, entire on 6; segm. 7 only with a narrow apical transverse streak, and 8 with a pair of apical annules; remaining segments unmarked, black. Segm. 10 dull, the entire dorsum and most of the sides very closely, microscopically, transversely striate; mid-dorsally, this segment carries in addition a number of scantily distributed rasp-like denticles, which are more or less definitely arranged in rows, whilst there is no longitudinal impression.

Auricles truncated apically, armed with 4 - 5 teeth.

Accessory genitalia not different from those of the allied species.

M. A. LIEFTıNek: Descriptions and records 0 ƒ S. E. Asiatic Odonafa. 383

Anal appendages shaped as shown in fig. 18 ; superior pair black, inferior appendage dark reddish-brown, its borders and apex black, Female (ad.) — Very similar to the male, but for the following differences; __ Head with the green frontal streaks distinct, though less sharply defined, and with the upper surface of the frons uniform brown, only the frontal crest being slightly obscured.

Synthorax uniform reddish-brown; green dorsal marks closely resembling those of the male, but lateral bands illlimited and pale bluish instead of green. Fore wings diffusely tinted with yellowish from the pterostigma nearly to level Of arculus and beyond that level in the costal and cubital spaces; hind wings palely and diffusely amber tinted but with the anal area and the apices, from distal side of pt backwards to the point where Cu. meets the wing-margin, hyaline. Pterostigma ochreous-brown. Abdomen spindle-shaped, contricted on segment 3, thence widened (greatest width over the middle of 5), finally again narrowed, with cylindrical segments. The two basal segments are brown, the remainder black. Pale markings definitely green, closely similar to male, only the lateral marks of segment 1 and 2 greatly enlarged, that on 2 in the form of a complete stripe running from base to apex of segment, parallel to the lower border of the tergite.

Anal appendages broken off in both females. Dentigerous plate shaped exactly as in the allied species.

Length: ♂ abd. + app. 42.5, hw. 34; ♀ (allotype) 38, 35; ♀ (paratype) 35, 33.5 mm.

Figures

Fig.18. Oligoaeschna mutata,sp. n. d‘. Analappendages, dorsalview and right side.