The Odoiiafa or Dragonflies of South Africa. 261 



altliough these tiny (iml fragile looking creatures are occasionally- 

 capable of verv rapid nioveuieuts. Their shape and coloration are in 

 most cases liigldy cryptic in their natural haunts. Under the influence 

 of conditions resulting from the full sunlight on open space, reflected 

 from the water's surface, or broken into the intricate maze of vegetation, 

 even their bright colours — metallic green, light azure blue or vivid 

 blood-red — cease to be conspicuous, and often vanish to a point which 

 is a just cause of admiration to an observant mind. 



In the fauna under discussion there is a fair representation of the 

 Suboi'der, and it is probable that a certain number of species will be 

 added to our list as the result of a more thorough investigation of the 

 country. 



There ai-e representatives of two families : 



A. Numerous antenodal cross-veins (Anq) ; the nodus distant a. long way 



from the wing base. Quadrilateral (q) nearly rectangular, long, crossed 

 by one or more veins (Plate VI, figs. 6, 7i . Calopterygidae- 



B. Two antenodal cross-veins only ; the nodus near the wing base. Quadri- 



lateral a single cell, nearly rectangular, or oblique in various degree 

 (Plate Vr, fig. 8, etc.) Agrionidae. 



lA. Family CALOPTERYGIDAE. 



This family is poorly represented in our fauna by two species 

 belonging to very widely removed genera. 



a. Wings petiolate (i. e. the vein A is for a short extent the actual hind 

 margin of the wing). Two of the antenodal cross-veins are decidely 

 stronger than the rest, and run right through from C to R. Quadri- 

 lateral two-celled. JI/4 strongly convex costal. 



A long and narrow pterostigma present in both sexes (Plate VI, fig. 6). 

 Ante- and postclypeus much enlarged, projecting in a Ijclmet-like 

 structure .......... Lihellaijo. 



aa. Wings not petiolate (i. e. there is a narrow anal field between vein A and 

 the actual hind margin of the wing right from the Ijase). All .antenodal 

 cross-veins about equal, and most of them running through from C to R. 

 Quadrilateral long and narrow, rectangular, with 5-6 cross-veins. 

 M 4 straight. Only e.xceptionally, and in the male sex alone, a small 

 pterostigma, scarcely larger than two or three cells (Plate \1. fig. 7). 

 Head of the regular zygopterous form Phaon. 



LIBELLAGO (Sclys, 1840). 



This genus is in Africa the representative of de Se'lys' " Legion 

 Libellago," a group of Caloptei-ygidae that might eventually rise to 

 the rank of a subfamily. 

 17 



