212 THE KNTOMOr.OtilS'r's KIOCOKD. 



climate dots modify to a slight degree even the underside of the 

 generation of the species in question, which emerges there during the 

 autumn and the winter. Some individuals are quite similar to nymo- 

 typical meijera, but others afford features I have not seen in any 

 European individual : they consist in a warmer, more reddish tone of 

 the yellow ground colour of the hindwings and in a duller and jialer 

 tinge both of the diffused scaling and of the streaks and eye-spots : the 

 former is often very thick and uniform ; the two latter are of the same 

 tone, so that they do not stand out at all ; the eye-spots are also 

 distinctly smaller than usual. To what extent this form is produced 

 and whether it is prevalent or not in certain localities I have not been 

 able to ascertain. It seems M'ell suited to afford protection on reddish 

 sandy soils. The extent of the black markings on the upperside is 

 considei'ably more variable in Africa than in most regions, because one 

 finds quite usually both forms as dark as nymotypical iiieijcra and 

 others approaching altieala and, thus, similar on that .surface to 

 jiracaiistralix and aiiytrali^. 



The well known tii/i'liiis, Bonelli {Moii. E. Soc. Scienze di Tmino, 

 XXX., pi. I., fig. 2), peculiar to Corsica and Sardinia, does not follow 

 the main line of vai-iation exactly and must be considered as a 

 particularly distinct collateral branch, which certainly is more distinct 

 from all the other races taken as a whole than the latter differ from 

 each other. For this reason, and because no individual of any otber 

 race; could be mixed up with iii/eliiin or vice versa, as I will point out 

 further on, one feels that tii/eliiis is at least a subspecies as compared 

 with vieijera, if it be not proved in future that they are actually two 

 species, like Ai/lais inticae, L., and ivhmisa, Bell, (see Eut. Bee, xxxi., 

 p. 3 99), according to uiy views. In its first generation the underside 

 features vaiy individually to a marked extent and occasionally do not 

 differ much from nymotypical }iu'iiera ; a characteristic form is produced, 

 however, quite commonly (transitional ones prevail), in which the 

 basal half of the hindwings, as far as the furthest of the two central 

 streaks, is covered with thick blackish scaling, whereas the outer half 

 is veiy sparingly dusted with them, the eye-spots standing out on a 

 space of clear groundcolour ; this, of course, is equivalent to the 

 obliteration of the band which precedes the eye-spots on the upper- 

 side ; this obliteration is the most prominent and better known 

 characteristic of tiiidius ; the underside can thus be described as 

 belonging to grade I. and similar to nymotypical iiienera in its basal 

 half and to grade lY. similar to ciiixtralis, or transitions to it, in its 

 further half ; also the tinge of the ground-colour is less yellow than in 

 vieijern, particularly on the outer part of the wing. It is interesting to 

 note that in the same islands one finds the race hjlhts, Esp., of 

 t'oenoni/inpha pauijiliiltis, L., which, in its first generation l;/llides, Vfty., 

 is distinguished from its other races by that very same division of the 

 underside of hindwings into a dark basal and a lighter outer zone. 

 Other characteristics of tiijelius are that it is considerably smaller than 

 any other uieijeru and that the upperside markings are reduced in 

 extent to a degree not met with even as an individual variation in 

 other regions; we shall see that the summer generations carry this 

 reduction still further; another noteworthj^ feature, which denotes a 

 tendency to vary along a peculiar line, different from the main one of 

 the species, is the large size of the apical eye-spot of forewing and the 



