156 Dr. F. A. Dixey on 
females.” * This dulness of coloration in the wet-season 
females mentioned is with some hesitation interpreted by 
Mr. Marshall as being protective in its object. The present 
is perhaps a fitting opportunity for pointing out that the case 
of these three Acrwas seems to bear some relation to a far- 
reaching principle which has met with less notice than it 
deserves, and as to the significance of which no suggestion 
has hitherto been made. The principle I refer to is 
this :—that the dry-season garb of a seasonally dimorphic 
butterfly, at least as regards its under-surface, is often far 
better marked and more persistent in the female than in 
the male. This is obviously of interest in view of Professor 
Poulton’s interpretation of the cryptic character of dry- 
season and desert forms.- It would accord with all that 
we know as to the special importance attaching to the 
life of the female, and the means that are taken for 
preserving it, that the more efficient mode of protection, 
such as on Professor Poulton’s hypothesis the dry-season 
colouring must be, should be mere completely and persist- 
ently adopted by the sex whose safety from enemies is of 
such vital moment to the species. The interest of the 
point perhaps justifies a slight digression, and I propose to 
give here a few instances which will serve to support the 
above generalization. 
NXanthidia nicippe, Cram. North and Central America. 
The wet-season female retains on the under-surface a 
tinge of the dry-season purple. 
LIvias pyrene, Linn. siete etc. Here also the wet- 
season female usually retains the dry-season mottling. 
Tvias marianne, Cram. India. The wet-season female 
is nearly always brown beneath, as are both sexes in the 
dry season. The under-side of the wet-season male is 
yellow. 
Catopsilia pomona, Fabr. Oriental and Australian 
Region. In the wet-season form (C. cvocale, Cram.)¢ the 
female often retains in some degree the dry-season 
* Trans. Ent. Soc. Lond., 1902, pp. 433, 434. It is hardly neces- 
sary to remark that the peculiar need for protection experienced by 
the female sex was first pointed out by Mr. Wallace. Some of the 
provisions towards this end were recognized by him as cryptic (as 
in many birds); others were supposed to be pseudaposematic. It 
is now known that synaposematism may also play an important part 
in the special protection enjoyed by female insects. See Trans, Ent. 
Soc. Lond., 1902, pp. 466, 467, ibique cit. 
+ Ibid., pp. 481-433, ete. t Ibid., p. 109. 
