192 KRITISH BUTTERFLIES. 



the rest of Switzerland, in consequence of having a broader blue area, are rare at 

 Tarasp. The Tarasp form is not found in the Valais. The underside is somewhat 

 darker than in the lowland form, lighter than in aegidion, Meissn. The ? s are 

 of the normal dark brown. Only in the mountain-region of Tessin, at Faido and 

 Dalpe, at about 1000 metres altitude, have I found similar specimens, and these 

 not of quite so deep a colour as our var. killiasi (Christ). 



This is the form of the southern slopes of the Swiss Alps, the J 

 of which has largely the general facies of the var. philonomus, but is 

 larger, and has a much wider marginal border to all the wings. We 

 have taken it commonly between Guarda and Lavin, at Brugnasco. 

 Piotta, etc. It is very near the aegon of the Austrian mountains. 



7. var. aegon, Schiff., " Sys. Verz.," 1st ed., p. 183 (note) (1775); Schneid.. 

 ; ' Sys. Besch.," p. 252 (1787). — The 14th (argus) and 15th (aegon) species differ 

 from the others in the bluish-silver eye-spots of the underside (" ocellis caeruleo- 

 argenteis," Linn., Sys. Nat. and Fn. Suec. de P. argo); but since this row of silver 

 spots on the hind-margin is common to the two species, the question follows : what 

 is the most constant mark of the difference between these ? In conjunction with 

 the broad black outer margin of the second, the width, twice as great, of the first, 

 and the black spots projecting into the blue ground of the hindwing from the black 

 border, the chief distinction is the undeniable difference between the caterpillars 

 which have now been discovered, and which once for all settled our long uncertainty 

 whether to divide these insects into two species, or to unite them in one (Schiffer- 

 miiller). 



This is evidently the Austrian valley form with broad black 

 margin to the wings, which we have from various localities in the 

 Tyrolean, and Carinthian, Alps, and of which there are several 

 specimens in the British Museum coll. Schneider described {Sys. 

 Besch., p. 252) the insect as follows: " Alis ecaudatis casruleis, 

 margine latiore nigro, subtus limbo ferrugineo, ocellis cseruleo 

 argenteis. Under this name the ' Wiener Verzeichniss,' pp. 185 and 

 183, mentions in its annotations a butterfly very like the preceding 

 (argus), and, apart from the totally different caterpillars, only to be 

 separated by the following distinctions — only half the size of the 

 preceding, the black border broader, and no black spots coming from 

 the border into the blue ground colour." 



5. var. aegiades, Gerh., " Mon. Schmett.," p. 19, pl.xxxiv., figs. 4a-c (1853).- 

 Tliis variety, which is specially found in this locality, is distinguished from typical 

 aegon by its size, by the absence of the line [discoidal spot] on the upperside of 

 the forewing, and the arrangement of the spots on the underside- North Germany 

 (Gerhard). 



The $ shows a large form of aegon, but the $ is smaller, the 

 underside in the plate is that of the latter. The white band within 

 the orange spots is much less distinct than usual, the outer of the two 

 subcostal spots of the underside hindwing is further from the base 

 than in the figure of the typical aegon, and there is a 1th basal spot on the 

 hind margin. There are, however, no metallic spots. The ? is brown 

 on the upperside, witli a succession of slightly lunular orange dashes 

 on the forewing forming a band, with a band of more definite lunules 

 on the hindwing, enclosing a. row of indistinct dark spots between 

 themselves and the hind margin. Wheeler adds: "A very usual form 

 of aegon in the Rhone Valley, e.g.. at Bouveret." It appears to us to 

 represent distinctly the " plain " form of Central Europe, except that 

 it has no metallic kernels to the marginal spots on the underside of 

 the hindwings. 



i . var. orient <il is, u. var. Sella, Stand., " I lor. Soc. Em. Ros.,"' xiv.. o. 234 (1878); 

 Lang, " Butu. Eur.," p. 106 (1884); Riihl. "Pal. Gross-Schniett.." i., pp. 232. 751 



