( 655 ) 



none of the African Kite-Swallowtails having all the subcostals free. The next 

 phyletic stage is represented by those sjiecies in which the first subcostal is 

 anastomosed with the costa, and in the third stage both the first and second 

 snbcostals aro joined to the costa. Both the less and the more advanced specialisa- 

 tions are observed among the American Papilios, some of the species exhibiting 

 a remarkable flnctnation in this respect among the individuals. 



The scent-organ in the abdominal fold of the hiudwing of the males is another 

 structure which exhibits interesting variety among these Papilios, and striking 

 variation within many of the species. The scent-scales differ in some of the 

 species enormously, while in others the differences are less marked, and in others 

 again the scent-scales are apparently identical. The geographical variation of the 

 scent-organ is very marked in several species of this Section. In quite a number 

 of American and Old-AYorld species the scent-organ is vestigial or absent, though 

 the fold remains always slightly indicated at the base of the wing.* 



The genitalia of the American Ivite-Swallowtails are ia some groups of great 

 nuiformity, while they are different in every species, and sometimes even subspecies, 

 in other groups. One organ, the tenth abdominal segment of the male, is however 

 of remarkable constancy all through the American species of this Section, with 

 the exception of one species (P. celfidori), which one would not expect to deviate 

 so much from the normal, considering that the aberrant-looking mimetic forms have 

 the tenth tergite of the same trifid type as P. protesilaus, dolicaon, marcellus, etc. 

 This exception from the normal is instructive. It is one of the instances we meet 

 with so frequently among Lepidoptera of the simplification of an organ by reduction, 

 the tenth tergite of P. celadon having become simple in consequence of the loss of 

 the side-lobes. 



The edge of the eighth abdominal tergite of the male is very characteristically 

 modified in the American Kite-Swallowtails, the smooth erect scaling at this edge 

 not being met with in other American Papilios. 



We know deplorably little about the larvae and pupae of the various species. 

 There are some points in the variability of the species, especially the mimetic 

 ones, which breeding from a female would put beyond dispute. Under P. phaon 

 and P. lysithous we have united quite a number of differently coloured forms which 

 other authors have considered distinct species. Though we have no doubt about 

 these insects being polymorphic, it is nevertheless desirable that this polymorphism 

 be investigated by breeding from the eggs. 



The following two generic names have American species as types : 



Iphiclides Hiibner, Verz. belt. Schmett. p. 82 (1818 ?) (type : dolicaon). 



Eurytides Kirby (ex Hiibner, indescr.), in Allen, JS'at. Libr., Butt. ii. p. 272 

 (1896) (type : dolicaon). 



Since some Old- World species are apparently close allies of American species, 

 and may perhaps come into one or the other American Group when we classify 

 all the Papilios, we abstain from giving a detailed characterisation of the two 

 Subsections in which the American Kite-Swallowtails fall. 



Subsection E. 

 Underside of wings with red spots at the base, or hiudwing with a red line 

 parallel to abdominal margin, extending from costal margin before middle towards 

 the anal angle. Snbcostals of forewing always free. 



* The result of our investigation into the variation of this organ will be the subject of a special pafer. 



