136 BRITISH BUTTERFLIES. 



Tribe : Strymonidi (Theclidi). 



The species in this tribe comprise the small black, or blackish-brown, 

 "hairstreaks," usually with one or two delicate tails to the hindwing, of 

 which Strymon pruni and Edwardsia w-album are our only British repre- 

 sentatives. They were first grouped, with one or two quite heterogeneous 

 species, by Hiibner, as the Strymones (Verzeichniss, p. 74), from which 

 they derive their modern tribal name. They are principally confined 

 to the north temperate zone of the Old and New Worlds, in each of 

 which they extend across the entire continent, the number of species 

 being very considerable, Staudinger and Eebel noting (Catalog, etc., 

 3rd ed., pp. 69-70) 16 species for the Palsearctic, and Dyar (List Nth. 

 Amer. Lep., pp. 37-38) 26 for the Nearctic, region. Both these 

 authors place the mass of the species included in this tribe in the 

 genus Thecla, Fab., which we have already shown (antea, viii., p. 313) 

 falls as a synonym of Ruralis, [Linne,] Barbut. De Niceyille records 

 (Butts, hid., iii., pp. 65 and 298) two Strymonid species as Indian, 

 viz., sassanides, Koll., which has apparently spread into the northwest 

 Himalayas from Persia, Bokhara, Fergana, etc., and sinensis, Alph., 

 which he includes among the Lycaenas, and which, he says, " is 

 thoroughly isolated in the genus Lycaena, and must take its place in 

 the small group formed by some very heterogeneous species — rhymnus, 

 Ev., tengstromi, Ersch., and anthracias, Chris." 



That this mode of grouping is very unsatisfactory, is evident even 

 from a mere cursory examination of the species in their various stages. 

 The eggs exhibit a great variety, compare those of pruni and w-album 

 (pi. ii., figs. 3, 4), which, in turn, are quite different from that of spini. 

 Similarly, the larvae show considerable structural differences, especially 

 with regard to the lenticles, which are so characteristic of the group. 

 The pupas, too, show considerable difference ; especially does that of 

 pruni differ from the others, so that one feels at once constrained to 

 look upon pruni, w-album, and spini, as representatives of three 

 groups within the tribe, and possibly several others will be noted 

 when the structure of the early stages of the Strymonid species 

 is sufficiently well-known. We may here note that Chapman's remark, 

 re the characters offered by the £ genital organs (antea, pp. 88-89), 

 points in the same direction. 



The general superficial characters of the Strymonids are clearly 

 indicated. All the imagines are of moderate size ; the hindwings 

 generally furnished with one or two rather short, thread-like, tails on 

 the outer margin, and towards the anal angle ; the forewings of the 

 $ usually with a well-defined, oval, androconial patch, as in the 

 Callophryids ; the neuration of the $ modified owing to the develop- 

 ment of this patch ; the underside remarkable for the possession of a 

 transverse white line, from which the popular name, ' ; hairstreak," 

 has been derived. The development of this line from the typical 

 Lycaenid ocellated spots, can readily be followed by a careful study of 

 the Asiatic group represented by ledereri, lunulata, etc. De Niceville 

 notes (Butts, hid., iii., p. 298) that, "the difference in the neuration 

 of the forewing, in the opposite sexes of the species of this group, is 

 considerable, and appears to be entirely due to the presence of the 

 secondary sexual mark of the <? ." Strangely, the Indian species, 

 sassa)tifles, described on the same page is without the sexual brand. 



