﻿LEPIDOPTÉROLOGIE COMPAREE 47 



some spécimens, the wall of the rein is chitinised for about the 

 terminal half, hère again there is individual and not spécifie 

 variation; for example in three spécimens from Val Veni (Cour- 

 mayeur), one has the faintest tinting, one has a fair amount 

 and the third is darkly chitinised. 



Thèse variations are illustrated in Figs. 37 to 42. 



Apart from the appendages, A^^/^j- can be separated from ail 

 races of Argus by the following points, and there are probably 

 others that hâve escaped me, as I am not adept at descriptions 

 of imagines. The marginal row of spots (or ocellï) on the 

 underside consists of a séries, each of which has a central black 

 spot (with metallic centre in some of those on the hind wing), 

 round this is a circle, orange basally, uncoloured marginally, 

 basai to this again is a row of black spots that may be regarded 

 as a further circle, expressed only at this side of the ocellus. 

 Each of thèse black spots of this inner row, has in Argus the 

 angular outline of an arrowhead, ni Aegus it is crescentic. It has 

 in Argus a sharp central point directed basally and at each end 

 a sharp point directed distally and between thèse on its distal 

 edge, it has an angular recess corresponding to the central point 

 on its opposite margin. In Aegus the inner and outer marginal 

 lines of each spot has a smooth regular curvature. This regular 

 curvature of the outer margin of this row of spots in Aegus and 

 its reentrant angle in Argus is perhaps the most constant and 

 characteristic feature in the form of thèse spots. In both species 

 thèse spots vary a good deal in their size, intensity, and in 

 showing thèse spécifie forms, but it is the case that Aegus never 

 has the angular outline except rarely on the basai side of some 

 hind wing spots, never on the fore wing, and Argus never fails 

 to show it in at least some of them and in many spécimens the 

 whole row shows the spécifie form, angular in the one species, 

 crescentic in the other. I hâve spoken of the orange mark of 

 each ocellus as a circle round the central black spot. It is 

 however only orange on its basai side. The colour of the mar- 

 ginal side differs in the two species. In Argus it is identical 



