Genus Hemistigma Kirby, 1889
piedspots
Type species: Libellula albipuncta Rambur, 1842
Introduction
One species is widespread and often numerous at open marshy habitats throughout tropical Africa, while a second is confined to Madagascar. The fairly small (hindwing 23-29 mm) H. albipunctum is recognised by its black-and-white pterostigmas. This feature, however, can also be seen in the deceptively similar Palpopleura deceptor (sometimes placed in the subgenus Hemistigmoides) and the related genus Thermochoria. Black-and-yellow at emergence, males turn completely pale grey-blue pruinose, the initially brown eyes attaining a similar colour. Black streaks develop in forewing subcostal spaces, females also develop dark wing tips. [Adapted from Dijkstra & Clausnitzer 2014]
Diagnosis
Male of genus is similar to Thermochoria by (a) frons rounded and without ridges; (b) distal Ax in Fw incomplete, its subcostal section absent (indicated as ‘½’ when Ax are counted); (c) Fw costa smoothly convex; (c) Fw supratriangles usually with 1-3 cross-veins; (d) Pt bicoloured, half white and half black, or wings with dark streaks at least in subcostal space of Fw, or both; (e) S4 without transverse ridge. However, differs by (1) all wings usually with 1 cross-vein in bridge spaces and 1 Cux, although rarely 2, but never 3 or 4; (2) Fw arculus proximal to Ax2, rather than distal; (3) Hw triangle of 1 cell, rather than usually 2; (4) 9½-11½ Ax in Fw. [Adapted from Dijkstra & Clausnitzer 2014]
Hemistigma albipunctum (Rambur, 1842). Female © Hans-Joachim Clausnitzer
Hemistigma albipunctum (Rambur, 1842). Male (mature) © Hans-Joachim Clausnitzer
Map citation: Clausnitzer, V., K.-D.B. Dijkstra, R. Koch, J.-P. Boudot, W.R.T. Darwall, J. Kipping, B. Samraoui, M.J. Samways, J.P. Simaika & F. Suhling, 2012. Focus on African Freshwaters: hotspots of dragonfly diversity and conservation concern. Frontiers in Ecology and the Environment 10: 129-134.
References
- Dijkstra, K.-D.B, and Clausnitzer, V. (2014). The Dragonflies and Damselflies of Eastern Africa: handbook for all Odonata from Sudan to Zimbabwe. Studies in Afrotropical Zoology, 298, 1-264.
- Pinhey, E.C.G. (1961). Dragonflies (Odonata) of Central Africa. Occasional Papers Rhodes-Livingstone Museum, 14, 1-97. [PDF file]
- Schouteden, H. (1934). Annales Musee Congo belge Zoologie 3 Section 2, 3, 1-84. [PDF file]
Citation: Dijkstra, K.-D.B (editor). African Dragonflies and Damselflies Online. http://addo.adu.org.za/ [2024-10-30].
