242 



Mr. H. Campion on some 



suture, and is bordered on each side by a streak of dark 

 brown ; otherwise, tlie sides of the thorax are yellowish 



brown. i i j 



In characteristic examples of brachi'ale, on the other hand, 

 the ground-colour is greenish tliroughout, with dark markings 

 as in chvysostigma, added to which there are two dark stripes 

 crossing the metathorax ; but in Nyasaland, at least, the 

 dorsum tends to become very pale, and the mesepimeral 

 stripe tends to take on a whitish hue. Just as the Lingadzi 

 specimens of hrachiale vary in the direction of chrij so stigma, 



Fig. 1. 



Fis-. '2. 



Fig. 3. 



Genitalia of tln-ee males of Orthetrum from the Lingadzi River, 



Nyasaland. 



Fig. 1.— O. bmchiale, P. de B., 23. ii. 15. 



Fig. •>. — O. brachiule, P. de B., 4. iii. 15. 



Fig. 3. — O. chrysodiyma, Burm., 8. ii. 15. 



P. Highley, cam. luc. et del. 



SO do the Monkey Bay examples of chrysostigma vary in the 

 direction of hrachiale^ and in many cases the thoracic colour- 

 scheme affords little guidance to the identification of the 

 species. 



The black markings on the abdomen are di.stributed in 

 different ways in the two species, but, as they are seldom 

 visible in dried specimens, they are not of n)uch value as aids 

 to identification. When semi-adult individuals are met with, 



