106 THE ENTOMOLOGIST. 



not the faintest trace of the marking — indeed, the first sub- 

 marginal lunule is almost obsolete. 



In the American Eiqjhoeades troilus a bright red spot is found, 

 but it is shifted back, and is a costal marking, appearing at the 

 upper end of the blue central band of the under wings ; but even 

 in this butterfly, where it is usually very stronglv developed, it is 

 not always to be found. Mr. Scudder, in his admirable work on 

 the 'Butterflies of the Eastern United States and Canada* 

 (p. 1317), writes of "a specimen in which the normally orange 

 lunule next the costal edge of the upper surface of the hind 

 wings has no orange in it, but is of the same greenish colour as 

 the other spots " ; and I fortunately possess in my cabinet a 

 similar example. Mr. Scudder does not state the sex of the 

 variety, but mine is a female — a most important fact, as will be 

 seen below, to my argument. Euphceades palamides does not 

 show a trace of the reddish sufi'used mark under consideration. 

 It is well here to remark that it often happens that the second 

 lunule of the hind wings has a trace of the reddish or orange 

 colour : this may be occasionally found in Papilio machaon. 



Enough has been written to illustrate the fact that through- 

 out several of the species of Papilioninse, belonging to at least 

 three different but more or less allied genera, there is a reddish 

 suffusion in the upper lunule or lunules of the hind wings — that 

 it is sometimes absent in species that usually possess it, but 

 that, as far as my experience goes, when so absent it is in the 

 male sex. The problem I have now to deal with is the significance 

 of such a trivial marking. Is it rudimentary of a coloration in 

 course of evolution ? or, on the other hand, is it vestigial of a 

 marking which has become partially, or even perfectly in some 

 specimens, obsolete ? I am inclined to hold the latter view, for 

 the following reasons : — In all the species dealt with there is, at 

 the anal angle of the hind wings, a more or less distinct ocellus, 

 with red pupil or patch : this is very well marked in Papilio 

 machaon. The red becomes more of an iris in some species, 

 because there is a black spot in the centre, as in P. xuthus, 

 P. polyxenes, P. brevicauda, P. zolicaon, and P. americus. In 

 Jasoniades and Euphoeades the ocellus is blurred, but the red 

 colour is to be found in every species of these genera at the anal 

 angle of the hind wings. 



Arguing from a priori considerations, one would be inclined 

 to consider that the reddish or orange suffusion in question was 

 the nearly obsolete trace of an ocellus which had once existed in 

 the ancestors of these butterflies. The question then arises as 

 to whether any facts can be adduced in support of such a 

 hypothesis. 



Africa is a continent which has not undergone those stupendous 

 geological changes which have affected so profoundly the 

 palsearctic and nearctic regions, from which my illustrations 



