390 ANNUAL, REPORT SMITHSONIAN INSTITUTION, 193 5 



the Andamans only the light form. Papilio paradoxus from the 

 Malayan regions is another species showing extreme variability. 

 Among our own swallowtails Papilio glaucus (pi. 8, figs. 30, 31 ; pi. 10, 

 fig. 41 ; pi. 12, fig. 65) is very variable in the female sex in the northern 

 half of its range, P. polyxenes (pi. 12, figs. 59, 60) is variable in the 

 male from Arizona and New Mexico southward, and P. hairdi (pi. 12, 

 figs. 55-57; pi. 13, figs. 67-70) has widely different forms in both 

 sexes. 



In a number of swallowtails, particularly in eastern Asia and east- 

 ern North America, the individuals appearing in early spring are 

 much smaller than, and more or less widely different from, summer 

 individuals of the same species. (See pi. 13, fig. 78, and pi. 14, fig. 

 89.) In others in the Tropics there are more or less marked wet and 

 dry season forms. 



Strange aberrations of all sorts, some of rather frequent recurrence, 

 are found in many species (pi. 9, fig. 40; pi. 12, figs. 61, 66). 



WHAT IS A SWALLOWTAIL? 



Many friends we recognize at once without appreciating just what 

 it is about them that enables us to distinguish them from many other 

 friends. It is the same with swallowtails. It is easier to distin- 

 guish them from other kinds of butterflies than to describe how it 

 is you do it. 



In the swallowtails all six legs are perfect and are used for walk- 

 ing in both sexes, and the longest joint (tibia) of the legs of the 

 first pair bears near the middle of the inner side a leaflike appendage 

 or epiphysis, as in the skippers (Hesperiidae) . The head is large, 

 but much less broad than in the skippers, and the bases of the an- 

 tennae are close together. 



Swallowtails are mostly large or very large, but a few are of 

 medium size and a very few are small. The very small ones are all 

 provided with enormously long tails. 



They are found throughout the world except in the extreme north, 

 in southernmost South America, in New Zealand, and in the highest 

 altitudes in the Andes. They are especially numerous and varied in 

 the Tropics, particularly in South America, northern India, and the 

 Malayan region, including the larger islands of the Malayan Archi- 

 pelago. The greatest variety of different types, however, is found in 

 temperate Asia. On the other hand, Africa has the least number of 

 different types, though the number of kinds found there is fairly 

 large. 



The largest local butterflies are swallowtails in every region of 

 the world except in South America, where these are surpassed in 

 size by some of the owl butterflies {Caligo) and the morphos. In- 



