410 A)innh of the South African Museum. 



aud also truly varietal), there remains scarcely more thau tlie very 

 small size for the definition of the female of exilis. In the present 

 specimen the shape of abdominal black bauds seems worthy of 

 mention : mid-dorsal band comparatively broad, nearly equally broad 

 throughout from segments 4 to 10, no terminal dilatations ; lateral 

 bands narrower, dilatations of posterior half only very slight on 

 segments 5 to 7. 



Abd. 13'5, hdw. 16, pt. < 2 mm. Ante-nodal cross-veins in front 

 wing 6^ . 6^ ; terminal triangles free. 



DiPLACODES Lefebvrei (Rambur, 1842). 



S. Afr. Mus. : 4 cJ, 5 9 , Lorenco Marques (24, 25 . ix, 22 . x, 3, 5, 

 13, 15 . xii . 1911) ; 1 (J , MTougosi, Zululand (x . 191 1, W. E. Jones) ; 

 1 cJ, Inhambane (xii . 1912, K. H. Barnard) ; 1 9 . Grwaai, S. Rhodesia 

 (16.ii.l912) ; Kaapuiuiden, Transvaal (xi . 1918, Tucker); S.W. 

 Protectorate, Otjituo (i . 1910, Lightfoot) ; Tsumeb (i . 1920, Tucker). 

 Coll. K. J. Morton: 1 c?, 2 9 , Beira (19 . x . 1908, Miss Fouutaiue). 

 Coll. Ris. : 3 cJ , 3 9 , Lorenco Marques (24 . ix, 26 . xi, 13. 15 . xii . 1911) ; 

 1 (? , 3 9 , Rikatla, Delagoa Bay (ix . 1913 ; iii, 17 . iv . 1914, H. Junod). 



The specimens here recorded indicate the southern limits of this 

 species, which is known from all parts of the African continent, 

 including the Mediterranean region ; it is also recorded from Asia 

 Minor, Syria aud Arabia, Madagascar and Mauritius, but not from 

 the Seychelles, where the Asiatic D. trivialis has been found. Con- 

 siderable variability in size, neural details (number of ante-nodal 

 cross-veins, internal triaugie free, two-celled, rarely even three-celled) 

 and colour pattern does not appear dependent on geographical 

 conditions, or colour varieties even when due to different stages of 

 maturity than on true individual variation. A number of names 

 given to such varieties by earlier and later authors was therefore 

 abandoned by the writer, following iu this the example of MacLachlan. 



The development of colour in male from a black and yellow pattern 

 similar to female to almost uniform black, according to maturity, as 

 found in D. Lefehvrei, has parallel cases, of which Sympetrum danae 

 from Europe, Northern Asia and boreal America is a long known one, 

 and another is Erythrodiplax nigricans, a South American species about 

 equally common in its habitat in the Argentine Republic. 



CROCOTHEMIS (Brauer, 1866). 

 A genus of predominantly African distribution. One of the African 

 species (^erylhraea) penetrates into Europe, even beyond tlie Mediter- 



