Dragonftles and their Prey. 241 



The only male of this species from the type-locality which 

 I have had an opportunity of examining is the one from 

 TenerifFe preserved in the British Museum (Natural History), 

 and referred to by M'Lachlan in Journ. Linn. Soc., Zool. 

 xvi. p. 177 (1882). The hamules of this specimen do not 

 correspond very exactly either witli the hamule figured by 

 Calvert or with that figured by Ris, but recalls the hamnle 

 seen in one or two specimens belonging to a series in the 

 National Collection from Prang, Northern Territories, Gold 

 Coast, in which the iiamules are particularly variable in form. 

 This series has been examined by Ris, and referred to 

 Orthetrum chrysostigma (Coll. Selys, Libell. fasc. xvi. (2) 

 p. 1081 ; 1916-1919), although the white juxtahumeral band 

 which especially characterizes that species is not very well 

 defined in any of the individuals composing it. 



In the series from the Lingadzi the hamule agrees very 

 well with what is found in two Gold Coast specimens deter- 

 mined for me as hrachiale by Dr. Ris, who pointed out that 

 in those specimens the hamule is larger than in the male 

 from No3si-b^ figured in his monograph {loc. cit. p. 199) and 

 in others seen by him from the Congo, etc. In these Nyasa- 

 land and Gold Coast males of hrachiale the hamule, viewed 

 in profile, is more like that of chrysostigma, but differs from 

 it in having the hook terminating the internal branch shorter 

 and slenderer, and also in having the external branch larger, 

 rounder, and more prominent. 



In addition to the nine males captured with prey. Dr. Lam- 

 born sent home forty-two otliers taken in the same locality. 

 Of these fifty-one specimens, forty-nine prove to have a more 

 or less common type of hamule (of which fig. 2 may be taken 

 as an example), one has the form figured by Ris for hrachiale 

 (fig. 1), and the remaining example may be referred to 

 chrysostigma (fig. 3). It may be observed that the kind of 

 hamule represented in fig. 1 is barely distinguishable from 

 thai; of 0. stemmale wrighti, from Seyclielles. Moreover, the 

 antenodals of that particular specimen of 0. hrachiale happen 

 to be dark, like those of the other insect mentioned. Never- 

 theless, the two species can always be distinguished from 

 each other by the difference in the coloration of the head and 

 the costa. 



When not obscured by pruinosity or by post-mortem 

 changes, the coloration of the thorax is normally quite 

 different in the two species, although the pattern itself 

 remains much the same in both. In chrysostigma the dorsum 

 is yellowish brown as far as the dark brown antehumeral 

 streak, and the lower ])art of the mesepistenmm is palo 

 brown ; a broad ivory-white stripe lies just below the humeral 



Ann. dj Mag. X. Hist. Ser. 9. ]'oI. viii. 10 



