1003 



of tiliae shows the extreme individual variability of this feature, as 

 well as of others. The transition of an unbrokeji middle-field to one 

 divided into an anterior and a posterior portion we therefore here 

 see take place under our eyes. 



We may likewise notice, that (he peculiarity of the central (5''i) 

 mark of the dark Bandline II, to differ in hue and size from the 

 other members of that series, is also present in tiliae, but in so far 

 in an opposed sense, that in some specimens it is distinguished by 

 a lighter instead of a darker shade. On its underside, tiliae shows 

 again the same simplified pattern as populi and ocellata, viz. the 

 two Handlines II and HI, with traces of I, IV and VI. 



The right here to speak of simplification, and to connect this 

 with the covering of light hairs stretching from the wing-root out- 

 ward as far as the middle area, is strikingly proved in this case by the 

 vestiges of the opaque central blotch (so strongly developed on the 

 upper side) which can also be detected on the under side. At the 

 root of each hair in the area of this dai'k middle-field a small black 

 speck may be perceived, and this produces the effect that the field 

 is seen in its full extension as a collection of specks, when we look 

 obliquely between the hairs. 



Still more striking than the resemblance between /z7/(7^ and öc^//a^a 

 is that between both these species and /rzrto;7Vzoi'/ï, this latter offering 

 so to say a form of transition between the first-named two. Here 

 the anterior part of the external margin of the opaque middle area 

 is not convex as in tiliae, but is concave, while a contrast both in 

 hue and in markings exists between the anal field of the wing and 

 the rest of its surface, the division of the central field in a fore- 

 and a hind-part thereby appearing as part of a process which extends 

 over the whole length of the wing-surface, in the same way as in 

 so many other Lepidoptera and even in Insects of other orders. 



It is likewise remarkable, that the apex of the fore-wing, which 

 shoAvs a special differentiation identical for all these species, viz. 

 that it is separated from the remaining markings by the oblique 

 light stria already described for populi, is dark greenish grey 

 instead of silvery grey, in contrast with the convex blotch along 

 the outer margin, which is stained in light grey, while it is dark 

 in others. 



On the hind-wing tartarinovii displays the same pink as ocellata, 

 and even traces of an eye-spot. 



On the other hand in tiliae a dark band extends over the entire 

 surface of the hind-wing parallel to the outer margin and at some 

 distance from it. This band evidently consists of as many components 



