Lestes spatula, Fraser, 1946

Fraser, F. C., 1946, Lestes spatula, a new species of dragonfly from the Argentine Republic (Odonata), Proceedings of the Royal Entomological Society of London 15, pp. 46-48 : 46-48

Lestes spatula sp. n.

Male. Abdomen 20 mm. Hind-wing 30 mm.

Head: labium pale brownish-yellow; labrum, clypeus and genae a dingy yellow (but probably blue during life) with three tiny brownish-black points on labrum, one of which is situated centrally; rest of head above dark brownish-black with small ill-defined areas bordering the lateral ocelli ochreous (in a teneral state, this dark area would be probably green metallic); beneath and behind head and eyes pale yellow but entirely overlain by a dense white pruinescence. Prothorax with dorsum dark bronzed black, ochreous laterally but this area overlain by dense white pruinosity including the anterior trochanters and coxae. Thorax dull ochreous with a narrow stripe on each side of dorsal carina metallic golden green, the middorsal carina broadly ochreous in between these stripes, which are pointed below and rounded above where they do not quite extend to the antealar sinus; a ‘similar metallic-green posthumeral stripe situated slightly posterior to the humeral suture, and broadening perceptibly below where it tends to lose its metallic sheen. A third metallic stripe appears to border the metepimeron anteriorly but is largely obscured by an overlay of white pruinescence which coats the sides and beneath of thorax. The pectus almost pure white with pruinescence and with no perceptible dark markings present. Legs dull ochreous, outer surfaces of femora, flexor surfaces of tibiae and whole of tarsi blackish. Wings hyaline: pterostigma covering 2 cells, elongate, tapering slightly but distinctly distally, dark warm brown with the distal and costal sides finely bordered with pale ochreous; 10 to 12 postnodals in fore-wings, 9 to 10 in the hind-wings, venation otherwise that for Lestes sens. strict. Abdomen ochreous beneath and along the sides and with a medial black line running the full length on the ventral surface: dorsally dark metallic green becoming coppery metallic from segments 5 to 7, segments 1, the apical half of 8 and the whole of 9 and 10 pruinosed white. Anal appendages: superiors dark blackishbrown, half as long again as segment 10, straight for rather less than the basal half, then evenly curved inwards for the apical portion, each completing a quarter of a circle. About 5 moderately robust spines lining the outer border of appendages, as well as some long, evenly-spaced hairs. On the inner side, the appendages are hollowed out and present a thin but prominent ridge which, beginning in the outer part of the hollow, runs outwards and ends on the outer border near apex of appendage; on the inner border a robust prominent subbasal spine directed inwards and backwards at an angle of about 45 degrees to the long axis of appendage; a second much smaller and quite inconspicuous spine situated also on the inner border near the apex of appendage. Between these two spines, where normally would be a more or less broad shelf-like process, the border of the appendage runs with a slight even concavity, the inner and outer borders thus being parallel to one another. Inferior appendages dark brown, of the same length as superiors, broad and cone-shaped at base and marked dorsally by two thin ridges which converge posteriorly: then abruptly narrowed and with sides nearly parallel to as far as apex which is obtusely rounded and furnished with some long hairs. Above, this appendage is hollowed out into a gutter which gives to the whole appendage the shape of a cheese-scoop.

Female. Abdomen 31 mm. Hind-wing 22.5 mm.

Similar to the male in colouring but the markings greatly reduced. Upper surface of head dull chocolate brown with a small irregular dark green metallic spot on each side of occiput and bordering the eye. Prothorax with only a small dark point situated on the middorsum of middle lobe. Thorax with the antehumeral stripes slightly narrower and dull coppery metallic in colour, whilst the posthumeral stripes are reduced to a mere vestigial streak confined to the lower part of the thorax; metepimeral stripe entirely absent. Pruinescence less dense than in the male although still marked on the lower parts of sides and underside of thorax. Wings evenly but very palely enfumed; pterostigma slightly longer than in the male, covering 2 1/2 cells, dark brown framed throughout its whole circumference in pale ochreous; 11 postnodals in all wings. Abdomen coloured as in the male but the metallic sheen becoming lost rapidly towards the posterior segments which are dark chocolate brown above, pale ochreous laterally and beneath; segments 9 and 10 pale dorsally and not pruinosed as in the male. Anal appendages and the underside of vulvar scales black, the former very shortly conical.

Habitat: A single very adult pair from Argentine: Concordia, -. xii.35 (Captain K. Hayward). Type in my own collection .

This new species, by the equality in length of the inferior and superior appendages, belongs to group forficula Selys and is distinguished by the entire absence of the inner shelf-like projection normally found in the superior appendages of Lestes . The inferior appendages are very similar in shape to those of the palaearctic L. sponsa Hans. , but the superior anal appendages of the two differ strongly. They also resemble in shape those of L. vidua Hagen , but in this species these appendages are much shorter than the superiors. In L. spumaria the inferior anal appendages are shorter and more slim, whilst the superiors are not at all curved in at apices. Finally L. forficula Rambur , scalaris Calvert , and bipupillatus Calvert , all have an inner shelf-like projection on the superior appendages, although but poorly marked in the last, to which species spatula appears to be most nearly related, differing, however, by the immaculate pectus.