130 



H. STEMPFFER 



Wing shape. £ fore wing inner margin feebly lobed basally : hind wing hind margin with a 

 sharp tooth at end of vein 3, a long and delicate tail at vein 2, and a delicate and much longer 

 tail at ib ; anal angle lobed. Male secondary sexual characters : midway on the inner margin 

 of the fore wing below there is a tuft of yellowish hair directed towards vein 2 ; on the upper- 

 side of the hind wing, between vein 7 and the upper edge of the cell, a greyish oval patch covered 

 with large oval erect scales and surrounded by a wide bronze shining area that fills the cell 

 and is covered with smaller scales. 



Wing venation (Text-fig. 294). The q* fore wing with 12 veins, $ with 11, vein 8 being absent. 



Male genitalia (Text-fig. 115). Uncus composed of two long sharp, slightly curved points, 

 separate almost to the base ; subunci rudimentary, subtriangular and scarcely visible ; 

 tegumen reduced ; vinculum broad, bearing on each side two large, triangular, weakly 

 sclerotized expansions ; in their natural position these expansions are joined to the lower 

 fultura by a membrane ; in silas the vinculum ends in a large triangular saccus, which is 

 lacking in the other two species of the sub-genus. Fultura inferior composed of a ring born 

 on a peduncle and surrounding the penis ; valves oblong ; penis short, massive, widely open 

 above basally ; vesica enclosing stout cunei ; uncus pilose, upper margin of valves only slightly 

 so. 



Among the many species placed in Argiolaus by Druce and other authors, only 

 two, lalos and crawshayi have male genitalia of the silas type. In the others they 

 are so different that it has been necessary to arrange them in new subgenera. The 

 area of distribution of Argiolaus even in this restricted sense is very extensive, 

 comprising the whole of East and South Africa from Abyssinia to the Cape, and the 

 species break up into more or less sharply defined geographical races, each of which 

 differs within the species not only in external appearance but also in the form of the 

 valves, which show constant modifications. 



The early stages of silas and crawshayi have been described by Murray (1935 : 

 75), Jackson (1937, Trans. R. ent. Soc. Lond. 86 : 214) and Pinhey (1949 : 104). 

 The caterpillars live on the flowers of various kinds of Loranthus which are parasitic 

 on trees inhabited by ants of the genus Crematogaster. 



Fig. 115. Iolaus {Argiolaus) silas silas Westwood, $ genitalia. 



