Mimetic Attraction. 319 



from the original Pierine form has been reached (1) by 

 a slight modification in shape and proportions of that 

 area of the pale ground colour included between the 

 diagonal bar and the dark inner margin of the forewing, 

 and (2) by the appearance of a submarginal series of 

 pale spots on both fore and hindwing (fig. 5, n). Both 

 of these changes mark an approximation towards the 

 characteristic aspect of the protected Heliconius atthis 

 group ; but the fiual link in the Pierine chain, viz., the 

 form represented in fig. 7, which appears to be the female 

 of P. locusta or of a closely allied species, brings us 

 nearer still. Here the pale area on the apical side of 

 the diagonal bar {ni) shows a tendency to be broken up 

 into separate spots ; and the pale ground colour, which 

 in P, viarcli ^ is uniformly yellow, in P. locusta ^ only 

 retains the yellow tint proximally, the subapical area (m) 

 and the submarginal spots {n) having resumed their 

 original white. These submarginal spots have also 

 diminished in size and become more compact in outline. 

 In all these respects a further approach is made towards 

 H. atthis, and the whole series from P. plialoe or P. calij- 

 donia to P. locusta ^ and H. atthis ati'ords as striking a 

 succession of transitional forms as that before traced from 

 the same ordinary Pierine types u-p to My lothris jyyrrha ^ 

 and Heliconius numata.'^ 



3. The " inachia " line. In this line an early step in 

 advance of the usual Pierine pattern is taken by Pieris 

 pandosia.f On the hindwing underside of this species 

 appears a narrow chestnut- coloured streak in the midst 

 of the dark hind-marginal band, running parallel with 

 the hind border of the wing. In P. leptalina, Bates (= 

 P. pisonis, Hew.), both surfaces of the forewing show a 

 diagonal dark bar as in P. calydonia $ and other species; 

 there is also a transverse dark bar crossing the under- 

 surface of the hindwing nearly parallel with the costa 

 (fig. 2). In P. pandosla, where the distal end only of this 



'* Trans. Ent. Soc. Lond. 1896, pp. G5-70. It should be added 

 to the foregoing that P. viardl $ itself is probably attracted by 

 H. charitonia, which may perhaps be considered an outlier of the 

 H. atthis combination. This is analogous to the attraction of 

 another intermediate term in the atthis line, viz., F. iJemophile ^ , 

 by the agna group. 



t Figured by Hewitson, Exot. Butt., "Pieris," pi. II., fig. 14, 

 and ihkl, pi. VI., fig. 39. 



