Euphaea impar Selys., 1859

M. A. Lieftinck, 1940, Descriptions and records of South-East Asiatic Odonata (II), Treubia 17 (4), pp. 337-392 : 341-344

Euphaea impar Selys.

1859. Selys, Bull. Acad. Belg. (2) 7, p. 441 -442 ( impar ), 442 ( inaequipar ). — ♂♀ Mt. Ophir, Malaya ( impar ), ♂ Sarawak ( inaequipar ).

1898. Kruger, Stett. Ent. Zeitg. 59, p. 78. — ♂ N.E. Sumatra.

1902. Laidlaw, P.Z.S. London, p. 87. — ♂ Kelantan.

1920. Laidlaw, Rec. Ind. Mus. 19, p. 27 (key, as subspecies) ( Pseudophaea ).

1920. Laidlaw, P.Z.S. London, p. 327. — ♂ Sarawak ( Pseudophaea inaequipar as sub­ species).

1924. Laidlaw, J. Mai. Br. Roy. As. Soc. 2, p. 298, 299. — ♂ Anambas I.

1930. Hincks, Sar. Mus. Journ. 4, p. 51. — ♂ Sarawak ( inaequipar , as subspecies).

1930. Ris, Mitt. Munch. Ent. Ges. 20, p. 85 (key), 85 -86 (♂ Mt. Ophir, ♂ Sarawak, descr.) ( impar + inaequipar ).

1933. Laidlaw, Bull. Raffles Mus. 18, p. 78. — ♂ Sarawak ( inaequipar ).

342 Treubia Deel 17, 1940, Afl. 4.

1935. Lieftinck, Misc. Zool. Sum. 92 - 93, p. 3. — ♂ S. Sumatra, notes (as subspecies).

1936. Kimmins, J.F.M.S. Mus. 18, p. 78 — ♂ Sarawak ( inaequipar ).

1936. Coomans, De Trop. Natuur 25, p. 73 -74, fig. 2 (♂♀ phot.). — ♂♀ W. Borneo ( impar inaequipar ).

Material studied: — Borneo. Leiden Museum : 1 ♂ Br. N. Borneo, Mt. Marapok, Dent Province, coll. G., “ Euphaea impar ” (Martin det.) ; 2 ♂, C.E. Borneo, Exped. A. W. Nieuwenhuis, Katoengan Mts., 1894, Max Moret. — Buitenzorg Museum: 16 ♂, 4 ♀, E. Borneo, Koetai , Sangkoelirang distr., V -VI. 1937, M. E. W alsh ; 1 ♂, C. E. Borneo Exped. Koetai , 22.VIII.1925, H. C. Siebers ; 11 ♂, 2♀ W. Borneo, Singkawang, Mampawa , Bengkajang & G. Ambawang districts, III.1931, I, II, III, VII, IX, X II.1932, V I.1933, and II.1934, L. Coomans de Ruiter .

In my ‘Synopsis of the Odonata of Sumatra’ (1935), I hesitated to believe that E. impar S elys and E. inaequipar Selys are different species, as was thought by Ris, who has been misled by the puzzling descriptions as given by Selys.

Now that I have once more compared a number of examples from South Sumatra with our fine series of males from W. and E. Borneo, I am deliberately of opinion that the two ‘species’ cannot even be regarded as subspecies. From Ris’s key, which is based on topotypical examples of both forms (one specimen each), it would appear that the opaque area of the hind wing of inaequipar is more extensive than it is in impar . This character does not hold good, for in our Bornean examples the extent of the opaque area varies from very slightly proximal to very slightly distal to the middle between nod and pt, while in my Sumatran specimens exactly the same variation is to be noted (1 proximal, 2 at middle, 1 distal).

As to the position and width of the blue mesepisternal band, I am unable to find any difference between the two forms; in both series the inner border of this band in dorsal view runs obliquely to the mid-dorsal carina; c.q. the black area enclosed by the two bands widens gradually from below upwards; and in only one of the Sumatran individuals the blue bands are somewhat more abruptly narrowed to above. In all specimens before me, these blue antehumeral bands on their ventral ends are definitely wider than the black spaces on both ends of the median carina: in some of the males from East Borneo even more distinctly so than in the Sumatran examples (cf. Ris’s notes, where it is just the reverse). The mesinfraepisternites of all specimens examined are spotted with blue: one small juxta-humeral spot and one somewhat larger ventral (median or posterior) spot. I have failed to discover any differences in the width or shape of the irregular black stripe bordering the ventral margin of the blue patch covering the thoracic sides, nor have I found any variation in the genital organs and anal appendages. Lastly, the shape of the hind wings as well as the measurements of the body are practically alike in the two forms:

Borneo ♂ abd. + app. 29 - 33, hw. 23 - 25 mm.

Sumatra ♂ abd. + app. 31 - 31.5, hw. 24.5-25 mm.

M. A. Lieftinck: Descriptions and records of S.E. Asiatic Odonata . 343

Female. — The ♀ of impar is probably less rarely come across than that of E. tricolor and its allies. The anterior parts of the head are bright greenish-yellow instead of blue, the labrum having occasionally a pale blue tint. Pale frontal spots band-like, broadly connected in the median line.

Dorsal thoracic fascia similar in principle to the male but dark reddishbrown instead of black. Sides dirty bluish- or olive-green with a diffuse brownish spot at the dorsal end of the humeral and second lateral sutures, and traces of brownish streaks near the lower margin of the mesepimeron, the metepimeron and round the spiracle. The dorsal margin of the pleurae is continuously bordered with dark brown. Venter of thorax pruinosed white.

Wings hyaline, or almost so; bases faintly yellowish. Abdomen brownish-black. There are small but quite distinct dorso-lateral yellow spots placed transversely along the bases of segm. 3 - 7; these spots are almost fused posteriorly with a lateral system of pale marks, consisting merely of straight, longitudinal stripes, greenish-yellow in colour.

Length: abd. + app. 2 5-2 7, hw. 23.5-25 mm.

E. impar is decidedly a shade-loving insect, preferring brooks and small streams in the depth of the forest. Apparently widely distributed and not uncommon in such places, where the males may be found perched on twigs in sunlit-openings high overhead.

Euphaea subnodalis Laidlaw ( fig. 2 ). 1915. Laidlaw, P.Z.S. London, p. 31-32. — ♂♀ Kina­ balu ( Pseudophaea ). 1920. Laidlaw, P.Z.S. London, p. 326, 327 (key ♂). — ♂? ♀ Kinabalu ( Pseudophaea ). 1924. Laidlaw, J. Mal. Br. Roy. As. Soc. 2, p. 298 (key) ( Pseudophaea ). 1930. Ris, Mitt. Munch. Ent. Ges. 20, p. 88 (key), 89. — ♂ Kinabalu. 1934. Schmidt, Arch. Hydrob. Suppl. 13, p. 326, p l. 17 fig. 4 (wings ♂).

Material studied: — Borneo. Leiden Museum: 5 ♂, Br. North Borneo, Mt. Marapok, Dent Province, coll. G. — Michigan Museum : 2 ♂, “ Kinabalu-gebirge, Nord Borneo, 1900, Rolle vdt.”, “ Euphaea tricolor Selys Subrasse montana m. Type, 1100 m, ♂ ” ( Förster det.). — Buitenzorg Museum : 1 ♂, Mt. Kinabalu, 16.IX.1913, J. C. Moulton (ex coll. Laidlaw) .

In addition to Kimmins’s 1) notes on the genital characters of the males o f E. tricolor Selys, subcostalis Selys and laidlawi Kimmins, I wish to include a few remarks on the closely allied E. subnodalis Laidlaw, based on material in the collection of the Michigan Museum, Ann Arbor, and in Dutch collections.

1) Cfr. D. E. Kimmins, “ The Odonata of the Oxford University Sarawak Expedi­ tion ”, Journal F. M. S. Museums, 18, 1936, p. 76 - 78, figs.

344 Treubia Deel 17, 1940, Afl. 4.

E. subnodalis takes rather an intermediate position between subcostalis and laidlawi in that the shape of the seminal vesicle on the second abdominal segment differs from both; its posterior margin is more convex than in subcostalis but less so than in laidlawi , whilst the lateral projections, though better pronounced than in laidlawi , are much less pointed than in subcostalis ( fig. 2 ).

The hind wings of the ♂ of subnodalis are decidedly narrower than those of the two species just mentioned.

The anal appendages are very similar to those of tricolor Selys; and, when looked at from aside, are almost of equal width from base to apex.

Figures

Fig. 2. Ventral aspect of seminal vesicle (top) and left side-view of anal appendages of Euphaea subnodalis Laid., from Mt. Marapok (bottom).