388 ANNUAL REPORT SMITHSONIAN INSTITUTION, 19 3 5 



SOME PECULIARITIES OF SWALLOWTAILS 



In their general appearance the true swallowtails {Papilio) show 

 great diversity, though in spite of their wonderful variety of form 

 and color they are structurally all very much alike. 



Most of the swallowtails have the hind wing produced into a tail- 

 like process that may be long and narrow, short and broad, acute or 

 spatulate, or even racketlike ; a few have two or even three tails — one, 

 indeed, possesses four. But some have merely a slight tooth where 

 the tail ought to be, and many have the hind wings simply rounded 

 with no trace of tails at all. The tail, when present, is stiffened and 

 supported by the prolongation of one of the veins of the hind wing ; 

 in Papilio elwesi and two related forms occurring in western China 

 and Formosa the unusually broad tail is supported by two veins. 



In the majority of the swallowtails the sexes are almost or quite 

 alike in form and in the color of their wings, but in many they are 

 very widely different. The females are almost always larger than 

 the males, usually slightly larger, but sometimes, as in Papilio para- 

 disea, very much larger. Very rarely they are slightly smaller ; in a 

 single case, Papilio antimachus, very much smaller. Usually the 

 males are more numerous than the females, and in quite a number 

 the females are as yet unknown. In a few, as Papilio priapus and 

 P. sycorax^ the females are more numerous than the males. Usually 

 both sexes inhabit the same territory, though the males are more 

 active than the females, so that they are more frequently seen in 

 gardens and in open country, and are more often caught. But in 

 some kinds, as Papilio aeneas marcius, P. sesostris sesostris, and P. 

 vertiminus diceros of the lower Amazon, the males are found in 

 swampy shades and the females in more open places. 



In some, as Papilio paradisea and P. dardanus^ the males possess 

 conspicuous tails, while the females lack all traces of them; and in 

 others, as P. Tnetnnon, the males are tailless and some of the females 

 have conspicuous tails. Some swallowtails, as Papilio polytes, 

 P. dardanus^ and P. meninon, have a varying number of different 

 types of females, though only a single type of male. A few have 

 several types of males but only a single type of female. Several, 

 as our Papilio bairdi (pi. 12, figs. 55-57; pi. 13, figs. 67-70), have 

 two or three or more different color types common to both sexes. 



Widely ranging swallowtails always differ more or less from one 

 region to another, and often are divisible into several or many dif- 

 ferent forms, esi^ecially if they range over the islands of an archi- 

 pelago, or throughout the higher valleys of an extensive mountain 

 system. Usually both the males and females show similar, or at 

 least correlated, local variation, but not infrequently this local varia- 

 tion is only evident, or at least conspicuous, in the females, far more 



