l06 Dr. F. A. Dixey on the phylogenetic 



3. Tlie white hand on the costal margin of the fore wing. 

 — Eeturning now to P. cardui and P. atalanta, we find 

 another conspicuous mark near the apex of the fore 

 wing besides those akeady noticed. This is the broad 

 white band passing inwards from the costa at the 

 junction of its outer and middle thirds, to which I have 

 already given the distinctive letter C. No question can 

 possibly arise as to the identity of C in these two species. 



Lepidoptera,' vol. ii., p. 276), between B. astyanax and Lartias 

 (Papilio) ])liilenor. This resemblance extends not only to markings 

 and colour, but to form and size as well. It is noticed by Bcudder 

 {op. cit., p. 287), but dismissed as insufficient to establish mimicry. 

 (5). The genus to whicli B. astyanax belongs contains undoubted 

 cases of mimicry in which the Basilarchias are the mimickers. 

 Tills raises a presumption in favour of B. astyanax mimicking 

 rather than being mimicked, which is strengthened by the fact that 

 B. astyanax has scarcely the aspect ot a typical Basilarchia. (6j. 

 In favom: of the view that B. astyanax, whether mimicked by 



A. diana or not, itself mimics L. pliilenor, are the facts given by 

 Scudder (vol. ii., p. 1251), on the autliority respectively of Edwards 

 and Doubleday, that the latter butterfly "has a strong and dis- 

 agi'eeable scent," and that " its flights are rather low and not very 

 powerful." It would therefore seem that L. philenoi' is specially 

 protected, and that it would be advantageous to another insect, 

 such as B. astyanax, to be mistaken for it. On the other hand, no 

 reason is alleged by Scudder why it should benefit A. diana to be 

 taken for B, astyanax, nor does he suggest that A. diana may 

 be taken for L. philenor. (It should be stated that IScudder fails to 

 verify the point as to the evil odour of L. jphilenor.) On the whole, 

 therefore, it seems to me that the evidence of mimicry between 

 L. philcnor and B. astyanax is much stronger than that between 



B. astyanax and A. diana ; and if, as Scudder thinks, the former 

 is insufficient, a fortiori, the latter must be also. I should wish, 

 however, to point out that even if it be conceded that A. diana J 

 is a mimicker, it does not follow that the gi'ound coloiu' was 

 acquired for that purpose ; it may merely have survived. More- 

 over, the spots of A. diana $ are those of a typical Argynnis. 

 The blacking-in of the base of the wings internal to series II. has 

 its counterpart in other American Argynnids [A, cybele, A. 

 nokvmis 5 > and especially A. leto $ ), and the only character that, 

 so far as 1 know, is really peculiar to A. diana among its relatives 

 is the large expanse of blue ground colour surrounding the spots of 

 series III., which I admit to be like the corresponding feature in 

 B. astyanax and L. philenor. Whether, therefore, such resem- 

 blance as exists between these insects be due to mimicry or not, I 

 see no reason to doubt that A. diana $ is a near representative of 

 the oldest type of the Argynnids, and so in all probability of the 

 NymjjJudidai generally. I may add to the above that Mr. Wallace, 

 in his lately published volume 'Darwinism,' 1889, p. 248, speaks 

 unhesitatingly as to the mimicry of P. jjJiilenor by L. Ursula 

 (Scudder's B. astyanax), but makes no mention in this connection 

 of *i. diana. 



