124 Dr. F. A. Dixey on 



like contrast between white, blackish brown and scarlet, 

 though here it is interesting to observe that on a close 

 comparison the scarlet streak in abnormis is seen to be not, 

 as in ornytion, on the costa of the hind-wing, but on that 

 of the fore-wing. The thin scarlet submarginal line, often 

 present in ornytion, is also absent from abnormis, though a 

 suggestion of it may occur in the form of a few scarlet 

 patches. Mynes geoffroyi, or rather the form doryca, 

 would present, as was observed by Wallace, the same 

 general appearance as abnormis, the contrasting colours 

 being very nearly the same. But here the relative position 

 of the scarlet touches is again somewhat different. Com- 

 paring doryca with abnormis, we see a rough correspondence 

 between the scarlet costal streak on the hind-wing of the 

 former and that on the fore-wing of the latter; also 

 between the scarlet submarginal spot on the hind-wing of 

 the latter and that on the fore-wing of the former. As in 

 abnormis. so in doryca, the hind-wing has no scarlet sub- 

 marginal line. The apex of the fore-wing is in doryca 

 diversified with certain light-coloured marks ; these are 

 absent from abnormis, but many specimens of ornytion 

 show a paler area, much less conspicuous than in doryca, 

 but in the corresponding situation. 



If these insects, after the usual manner of butterflies, 

 depress the fore-wings during the periods of protracted 

 rest, so as to conceal the white portion of the fore-wing 

 and leave visible only the apex of the fore-wing and the 

 whole expanse of the hind-wing, the resemblance between 

 them becomes perhaps even more detailed. The costal 

 and submarginal red marks fall more nearly into their right 

 relative positions, irrespective of their situation on fore- 

 or hind-wing ; and the assemblage is now joined by another 

 Delias from New Guinea, viz. D. irma, Frulist. In the 

 male of this butterfly the under surface of both wings is 

 black, with the exception of a scarlet patch on the costa 

 of the hind-wing, like that of D. ornytion, but somewhat 

 shorter in proportion; there may also be a powdering 

 of orange-yellow scales about the distal end of the cell 

 in the fore-wing, though this is often evanescent or 

 absent. 



It is difficult to see how the facts with regard to these 

 four insects can be interpreted without recourse to the 

 theory of mimicry. The resemblance between two of them, 

 as has. been seen, has been sufficient to cause great coil* 



