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The Differentiation of Species 



Many features are of value in determining the 

 species. 



1. The Wings : — 



{a) Tliey may shew areas of dark scales on 

 the costa, auxiliary, and first longitudinal veins, 

 producing the main spots of the wing. 



(5) Small areas of scales on the second to sixth 

 long veins ; less dark and distinct than the large 

 costal spots. 



(c) Pale areas on the wing fringe. 



(a) The markings on the wing are fairly constant in each 

 species, but variations occur, so that the spot may be longer 

 or shorter, giving the wing a darker or lighter aspect in the 

 same species. Thus in N. stephensi the following variations 

 in the second costal spot may be encountered (Fig. 51). 

 Especially does this variation occur in the wing of males. 

 The costal spots may also be confluent. They may depart 

 from their typical shape, as is frequently seen in the T spot 

 of M. rossii. 



(b) The smaller spots on the wing field along the course 

 of the veins are also useful for determining species. Thus 

 M. leucophyrus has six spots on the sixth long vein, while 

 M. elegans has only four. The extent to which the third 

 longitudinal vein is scaled is also of specific importance 

 (Fig- 52). 



(c) The wing fringe has at the points, where the long 

 veins cut the margin, a variable number of light areas. Thus 

 A. punctipennis has only one pale area, while A. pseudo- 

 punctipennis has many. Another exarhple of this means of 

 distinguishing species is given in the figure (Fig. 51). 



2. Leg Markings : — 



(a) Uniformly coloured as in the second 

 division of Myzomyia. 



(b) Speckled or banded, chiefly in the genera 

 Nyssorhynchus and Cellia. The banding of the 

 legs is of great importance in distinguishing the 



