Lestes praevius, M.A. Lieftinck, 1940

M. A. Lieftinck, 1940, Descriptions and records of South-East Asiatic Odonata (II), Treubia 17 (4), pp. 337-392 : 344-347

Lestes praevius , sp. n. ( fig. 3 ).

Material studied: — 1 ♂, 1 ♀ (ad.), E. Borneo, N. Koetai, Sangkoelirang distr., Maloewi , April 1937, M. E. Walsh leg. — 2 ♂, 1 ♀ (ad.), Enggano Id. (off the S.W.-coast of Sumatra ), Boeah-boeah , May 30, 1936, J. K. de Jong leg. Holotype d ♂ and allotype ♀ Maloewi, E. Borneo, April 1937, in the Buitenzorg Museum .

Male (ad.). — Labium pale yellow. Mandible-bases, labrum, genae and anteclypeus, blue. Postclypeus black with two large blue spots on either side of the middle line. Remaining parts of the head bronzy-black; no pale spots behind the eyes. Rear of the head pruinose blue. Antennae brownish-black.

Prothorax dull bronzy-green above, sides blue, strongly pruinose; a thick black stripe over the transverse suture of propleuron. Synthorax, colours faded, Russian blue on mesepimeron. Dorsum marked by a pair of dull metallic-green antehumeral stripes, shaped similarly to those of L. praecellens and only little broader than in that species, straight on their inner border and well separated from one another by a distance scarcely narrower than their own width, deeply crenulate or lobed on their outer border. Each of these bands is surrounded by a blackish line that neatly follows the crenulations, the median interstice being of the same colour. Mesepimerites marked with two (or three) blackish dots; one on the upper end of the humeral suture and one, distinctly larger, shoulder-spot on the middle of the lower portion of the mesepimeron; this humeral spot is connected by a vague patch of brown to a blackish point along the lower end of the humeral suture.

Sides o f the thorax with a black dot at lower end of the incomplete first suture and a slightly larger, triangular spot covering the spiracle. Two posterior black dots along lower margin of metepimeron. Venter of thorax pale-coloured, poststernum with two black points, one on each side of the median line. Sides and under surfaces rather coarsely powdered with light blue.

Coxae yellowish, striped with black posteriorly, heavily pruinose blue.

M. A. Lieftinck: Descriptions and records of S.E. Asiatic Odonata . 345

Femora dirty yellow with a thick black exterior stripe and a fine lateral line. Tibiae bright yellow, or greenish, exteriorly, black inside. Tarsi and spines black.

Wings hyaline, pterostigma deep black. Neuration as for genus, similar to typical praemorsus but the wings are definitely less abruptly petiolated and the nodal index is higher. Postnodals (type, Borneo), (paratypes, Enggano).

Abdomen marked similarly to praemorsus ; dorsal marks dull bronzy-green, those on 2 - 7 after the slight sub-apical constriction a little more expanded, and with the basal blue annules a trifle larger than in that species. Segm. 8 - 1 0 black, each with an ochreous point on the middle of the sides. Abdomen with segm. 1 pruinose blue aside and underneath, otherwise not pruinose.

Superior anal appendages light yellow, extreme bases and exterior teeth sharply defined black. Inferior pair pale reddish-brown, \ellow interiorly. Superiors forcipate, gently and regularly incurved, to meet at their apices, each with a strong sub-basal intero-dorsal tooth and with the interior sub-median projection armed with three strong unequal teeth. Inferiors broadly triangular in ventral view, divaricate, tapering, the tips rounded, not projecting beyond the level of the subbasal tooth of the superior appendage, fringed apically with a bunch of golden yellow hairs (omitted in the left figure).

Female (ad.). — Generally similar to the male, but for the following differences.

The whole of the anterior surface of the head, as far upwards as the insertion-point of antennae, dirty yellowish-brown. Postclypeus with two diffuse brownish spots. Frons marked off laterally by a narrow bronze-green streak which is connected with the dark colour on the upperside of the head. Metallic-green colour on the vertex reduced: antennae and ocelli surrounded by large, confluent yellow rings, so that only the interspaces remain bronze-green. Epicranial lobes entirely dull bronze-green. Occipital area yellowish, sutures and a few points on either side, brown. Rear of the head black, slightly pruinose. Antennae dark brown, articulations between basal joints yellow.

Pro- and synthorax isabella-coloured, the former slightly pruinose white, laterally. Bronze-green spots on dorsum and sides of thorax distinct, similar in principle to those of the male, but considerably more reduced. Mesepisternal bands narrow, the pale interstice equal in width to the bands themselves. Lateral brown spots distinct, arranged as in the opposite sex. Infraepisternites and lower portions of metepimera pruinose-whitc, as are the underparts of the thorax and the outer surfaces of all coxae.

346 Treubia Deel 17, 1940, Afl. 4.

Wings hyaline, pterostigma shaped as in male, dark brown in colour (type), or grey-brown (parallotype). Postnodals 14.14/13.13 (type), 16.17/15.16 (parallotype).

Abdomen robust, with cylindrical segments. Ground-colour pale olive- yellow, basal segments intermingled with green. Dorsal marks light bronzy brown with slight metallic lustre on basal segments; apical expansions very distinct. Terminal segments black, 8 and 9 each with an ochreous (or bluish) lateral spot, whilst 10 is brown with two small dorsal spots, most of the sides being yellowish in colour.

Valves black, with a pale median spot and with the serrulate lower margin also yellowish; border very slightly convex in lateral view; tips not surpassing end of segm. 10. Anal appendages bright yellow, a little longer than tenth segment, much depressed, lanceolate, with pointed tips.

Length: ♂ abd. + app. 34 (type, Borneo), 35.5-38 (paratypes, Enggano), hw. 22.5 (type), 24-24.5 (paratypes); ♀ 30, 23 (allotype, Borneo), 34, 28 (paratype, Enggano).

The specimens from Enggano are exactly identical with the Bornean type, save that the obscure lines bordering the trifid bronze-green marks on the dorsum of the thorax are unapparent. The ground-colour of the dorsum and sides of the thorax (faded in the type from Borneo), according to Ridgway’s colour standards, may be best described as ‘burn blue’ in the other males.

This new species is the fourth representative of a small species-group, or ‘Artenkreis’, of which L. praemorsus Selys, originally described from the Philippines, was the first to be reported. This last-mentioned species ranges from India to the Bismarck Archipelago; and although it will doubtless be possible to distinguish a number of local races for it, the separation of the many insular forms is by no means easy for each subspecies presents a considerable amount of colour variation 1). It is my hope to deal with them in due time since I have now been able to study topotypes of this species.

The three other species are I think certainly very closely related to L. praemorsus , but two of them at least present some striking morphological peculiarities, or even colour-differences, which I suppose are constant and of specific value. These species all occur within the limits of the area of distribution of praemorsus :

L. pertinax Lieft. (Nova Guinea, 15 Zool. 5, 1932, p. 493 -495, fig. 1. — Terra typica: New Guinea.

L. praecellens Lieft. (Treubia, 16, 1937, p. 59-62, fig. 2 - 3 . — Terra typica: Java.

1) Cfr. Schmidt, Arch. Hydrobiol. Suppl. 13, 1934, p. 331 - 334, figs. 20 - 27.

M. A. Lieftinck: Descriptions and records of S.E. Asiatic Odonata . 347

L. praevius , sp. n. (huj. op.). — Terra typica Borneo; further distribution: Enggano Id. 1).

L. praevius differs from praemorsus in the evenly curved shape of the superior anal appendages, which at the end of their second third are armed with a few robust interior teeth, absent in praemorsus . It further differs from typical examples (and from the indo-malaysian subspecies decipiens Kirby as well) in its superior size, shorter and black pterostigma, in its less petiolated wings, and in details of colouring.

L. praevius is easily distinguished from praecellens by the presence of blackish dots on the metapleurae of the thorax.

Lastly, our new species differs from pertinax chiefly in the longer inferior appendages. In their outward appearance, colour-design and pruinescence, praevius and pertinax are very much alike, whilst the shape and armature of the superior appendages of the male are also strikingly similar in these two species. For these reasons praevius may ultimately prove to be a subspecies of the Papuan pertinax .

Figures

Fig. 3. Lestes praevius, sp. n. Male anal ap­ pendages, dorsal view (left side), and right side-view.

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