386 ANNUAL REPORT SMITHSONIAN INSTITUTION, 19 3 5 



venient leaf with fully expanded wings exposed to the direct rays 

 of the early morning sun, and it is still feeding long after the other 

 kinds have gone to sleep hanging from a leaf. 



This habit of sleeping hanging from a leaf, common to most swal- 

 lowtails, has the great advantage that escape for a large and none 

 too agile butterfly is easy in case of an attack by enemies, either fly- 

 ing or tree-climbing creatures. But it has the disadvantage that 

 if a wind arises, the insect will be blown against the neighboring 

 leaves, and the outermost portions of the wings, the tails, and the 

 adjacent portions of the hind wings, will suffer damage. The torn 

 hind wings of swallowtails are evidence of the precariousness of 

 their roosting places at night, not of attacks by birds. 



Though relatively large, powerful, and swift, swallowtails seem 

 to be almost entirely devoid of the exploring spirit. They do not 

 indulge to any great extent in the migrations so characteristic of 

 some other types of butterflies. 



Only 18 kinds of swallowtails have been reported in migratory 

 flight. In North America the giant swallowtail {Papilio cresphontes, 

 pi. 9, fig. 37) and the spice-bush swallowtail {P. troiliis, pi. 11, fig. 

 49) have once been reported at the end of August and early in Sep- 

 tember migrating at Point Pelee in western Lake Erie, together 

 with that well-loiown wanderer, the common milkweed butterfly 

 {Danais plexippus). But not infrequently stray individuals of 

 various swallowtails may be found more or less far from their nor- 

 mal habitat. Thus I have recorded the zebra swallowtail {Papilio 

 marcellu^^ pi. 13, fig. 78) from Boston, Mass., and it has also been 

 recorded from Vancouver Island; the giant swallowtail {P. cres- 

 phontes^ pi. 9, fig. 37) has been recorded from Maine and Nova 

 Scotia, and I once caught one near Boston; and the southern mag- 

 nolia swallowtail {Papilio palamedes^ pi. 11, figs. 47, 48) has been 

 caught at Philadelphia. However, such sporadic occurrences cannot 

 properly be considered as evidence of true migration. 



In British Guiana great numbers of a silky white swallowtail 

 {Papilio philolaus) were once observed flying all in the same direc- 

 tion, mostly in a steady way, but a few resting here and there upon 

 the ground. There are no other notices of swallowtail migrations in 

 America. 



It is curious that only the giant swallowtail {Papilio cresphontes^ 

 pi. 9, fig. 37) has been reported from Bermuda, although our small 

 least sulphur {Eurema lisa) sometimes visits the islands in enormous 

 numbers, and the yellow clover {Euryinus philodice pMlodice) and 

 one of our wood-loving wood nymphs or satyrids {Enodia port- 

 landia) are among the islands' 14 butterflies. 



The common yellow swallowtail of Europe {Papilio machaon) 

 appears to have had a migration in the north of France, in the 



