BUTTERFLIES OF THE DISTRICT OF COLUMBIA 175 



The blue swallowtail is especially a butterfly of open fields with 

 an abundance of tall flowering plants in the vicinity of woods, of 

 flower gardens, and of orchards at the time of flowering of the fruit 

 trees. It is also to be found in open woods, especially along the road- 

 sides. It is familiar to all who maintain gardens in the vicinity of 

 Washington. 



There are four specimens in the Schonborn collection, one, dated 

 August 12, very large and evidently raised. A pupa is dated May 3, 

 1883. Mr. Shoemaker has specimens from the District. 



Habits. — This butterfly has a wild impetuous flight, dashing from 

 side to side and up and down and often doubling on its course in the 

 most erratic manner at an average height of 3 to 5 feet above the 

 ground. It is extremely nervous, and when feeding always keeps its 

 wings in motion. But in spite of its intense activity and its restless 

 nervous actions it is the least suspicious and least shy of all our local 

 swallowtails. 



It is preeminently a hot- weather butterfly and is seen to best advan- 

 tage and in the greatest numbers only on the hottest summer days, 

 from about 10.30 to about 3 o'clock. 



On hot days it is noticeable that the females have a less impetuous, 

 less irregular, and weaker flight than the darker males, though in the 

 broader features by which the flight of the blue swallowtail differs 

 from that of the other local species it is quite the same. 



On occcasion this swallowtail may become aggressive. Once I 

 was watching a male dashing irregularly about a field when an Eng- 

 lish sparrow {Passer domesticus) rose from the grass. The butterfly 

 at once made after it and followed it for 50 feet or more, as far 

 as the apple tree into which it flew. 



This incident enables me to say that the speed of this butterfly 

 and that of a frightened sparrow are approximately equal — roughly 

 about 25 miles an hour. 



This butterfly is extremely fond of flowers, especially such as 

 grow from 3 to 5 feet above the ground or even higher, as the flowers 

 of the lilac, peach, plum, buttonbush, and thistles, and various garden 

 shrubs. But it also feeds greedily on the flowers of the butterflyweed, 

 of other milkweeds, and of the red clover. In gardens, in common 

 with the other swallowtails, it is most strongly attracted by the 

 flowers of the lilac, the syringa, and the butterflybush. 



Seasons. — The blue swallowtail appears about the last week in 

 April and continues to emerge during May and the whole of June, 

 remaining on the wing until about the end of July. The females 

 appear at the same time as the males, and I have found both sexes 

 frequent as early as May 4. In spring it is much less numerous than 

 the other swallowtails — in fact, it is usually very scarce. It appears 

 again shortly before the middle of August, increasing in numbers 



