Mimicry in certain Butterflies of Neiv Guinea. 125 



fusion, even on the part of skillet! entomologists; and it is 

 hardly necessary to point out the improbability of this 

 striking resemblance between insects differing in affinity, 

 but all inhabiting the same region, being due to simple, 

 coincidence. Nor. again, is it easy to suppose any factor 

 in the climate or external conditions of New Guinea which 

 conld lead directly, on the part of three or four of its butter- 

 flies, to the assumption of a dark underside with red 

 markings; these markings, be it observed, belonging in 

 some cases to the fore-wing, in others to the hind-wing, but 

 always contributing to the same general effect. Whether 

 the explanation founded on mimicry is adequate, can 

 only be finally decided by observation and experiment; 

 at present I think it must be admitted to hold the 

 field. 



The scarlet markings on the hind-wing underside of 

 Delias ornylion would seem to be an attenuated version ol 

 the subcostal red patch and submarginal red band seen 

 in the corresponding position on the hind-wing of Delias 

 harpalyce, Donor., and Delias nigrina, Fabr. This series 

 of markings has a wide distribution among the species of 

 Delias, being more or less completely represented in such 

 species as D. aganippe, Donov. (Australia); D. Jcummeri, 

 Ribbe, iltis, Ribbe, and bakeri, Kenr. (New Guinea); 

 D. my sis, Fabr. (Australia) ; D. argenthona, Fabr. (Aus- 

 tralia); D. caeneus, Linn. (Moluccas); D. eucharis, Drury 

 (India); D. stolli, Butl. (China); D. eumolpe, Gr. Smith 

 (Borneo). A comparison of these and other forms appears 

 to favour the conclusion that in D. ornytion we have the 

 red submarginal series in an obsolescent, rather than in 

 an incipient stage ; and it is observable that although the 

 subcostal scarlet patch is persistent throughout the whole 

 range of this species, the submarginal scarlet line, which is 

 nearly always present in specimens from Eastern New 

 Guinea, and is well marked in a specimen from the Louisiade 

 Archipelago, has, in all the examples known to me from 

 Western New Guinea and the adjacent islands, completely 

 vanished without leaving a trace. Now it is to be remarked 

 that the failure of the red line in D. ornytion brings its 

 underside, with closed wings, into relation with that of 

 Delias inferna, Butl. (or as Fruhstorfer calls it when it. 

 occurs in New Guinea, J), irma). On the mimetic hypo- 

 thesis, it would be natural to ask whether the darkening 

 of inferna has been influenced by ornytion, and the loss of 



