366 



the foregoing, is found on the base of the discocellular vein, i.e. 

 the point of the v-figure in Vanessidœ and PapilionidcF. 



Aporia cratœgi (fig. lo). 



In Aporia cratcegi the two rows of Hght spots have disappeared 

 and the interveinal pigment has concentrated itself to as many 

 rows of large black patches. Those of the outer row show the 

 usual triangular form with rounded bases. In the first anal 

 cell the two spots of both series clearly show their double nature, 

 the original eighth and ninth spots having only partly coalesced. 



At the beginning and the end of the rows, longitudinal black 

 bands are found, marking the borders of the wing, and mani- 

 festly owing their origin to the coalescence of the first and last 

 spots of the inner row with the corresponding ones of the outer. 



The outer corner of the discoidal cell is always marked by 

 a big black patch. 



When a sufficient number of specimens are examined, a 

 considerable variability in the size of the blotches and the degree 

 of their coalescence is seen to exist — a fluctuation which likewise 

 occurs in Pieris brassicœ, and, in a somewhat different manner, 

 in Papilio machaon. The black network of the veins is not 

 strongly marked in .4. cratœgi, the inferior border- vein of the 

 discoidal cell being once more the broadest. 



Euchloè cardamines (fig. ii). 



The wing-sheath of Euchloè (Anthocharis) cardamines seems 

 at first sight built after a wholly different plan, but on second 

 consideration the same features are easily recognised. All 

 the veins are marked in one and the same way by lighter bands 

 in high relief, somewhat resembling the structure of the longi- 

 tudinal veins in P. podalirius. but without the network of side- 

 branches which is typical for this latter species. 



But in cardamines these bands are much broader, and present 

 a double character, their middle line being traced by a sharp 

 groove. The interveinal spaces also resemble each other in 

 presenting one and the same aspect — that of a dark ground- 

 colour divided by a light middle stripe. 



The latter stands out in high relief as a series of irregular 



