SWALLOWTAIL BUTTERFLIES — CLARK 389 



rarely only in the males. One wide-ranging swallowtail in southern 

 Asia, Papilio polytes, has 4 different types of females in one region, 

 3 in another, 2 in another, and in some places only 1. 



It is a most curious fact that in many regions all the native 

 swallowtails, in other regions the majority, or several, differ from 

 the corresponding forms in adjacent regions in certain definite ways. 

 Bates pointed out that species in three distinct groups which on the 

 upper Amazon and in most other parts of South America have 

 spotless fore wings acquire white or pale spots on the fore wings 

 in the lower Amazon region and about Para. As was pointed out 

 by Wallace, the swallowtails of Sumatra, Borneo, and Java are 

 almost invariably smaller than the allied forms in the Moluccas and 

 in Celebes. No less than 14 kinds in Celebes and the Moluccas are 

 from one-third to one-half again as great in extent of wing as the 

 corresponding forms in Borneo, Java, and Sumatra. The species 

 in New Guinea and in Australia are also, though in a less degree, 

 smaller than their closest representatives in the Moluccas. In the 

 Moluccas themselves the forms found on Amboina are the largest. 

 The forms on Celebes equal or even surpass in size those of Amboina. 



Species that are tailed in India become tailless to the eastward 

 on the islands of the Malayan archipelago. In America all except 

 two of the very numerous Aristolochia swallowtails occurring between 

 Costa Rica and southern Brazil are without tails, whereas nearly 

 every species occurring from southern Brazil southward and from 

 Costa Rica northward is provided with tails. 



Almost every species of swallowtail on the island of Celebes has 

 the fore wings more elongate and falcate than the corresponding 

 forms elsewhere, with the anterior margin much more strongly curved 

 and usually with an abrupt bend or elbow near the base. 



In many swallowtails there is great individual variation. Most 

 conmionly this is confined to the females. Sometimes it is equally 

 evident in both sexes, and rarely it is seen chiefly in the males. Varia- 

 tions may be of constant occurrence or sporadic. They may occur 

 throughout the range of a species, or they may be confined to certain 

 regions within that range. In Papilio memnon of eastern India and 

 the Malayan region the females, which may be either with or without 

 tails, are most extraordinarily variable in color and color pattern, 

 except on the Riu Kiu Islands, where there is only a single type of 

 female. Even more variable are the tailless females of the African 

 P. dardanus; but in the form occurring on Madagascar the sexes are 

 alike. In Papilio clytia from India and the Malayan regions both 

 sexes are very variable. The dark forms show division into geo- 

 graphical races, but the light forms, though very variable, do not. 

 In the Philippines and Palawan only the dark form occurs, and on 



