164 BULLETIN 15 7, U. S. NATIONAL MUSEUM 



height of 3 or 4 feet above the ground, but when passing through 

 groves of trees fringing the banks of streams it may zigzag up 

 to a height of 20 or 30 feet or more. 



The females are easily distinguishable from the males when on 

 the wing by the difference in color and by their less energetic and 

 less erratic flight. They also pause more frequently to feed. 



The flight of both sexes of this butterfly is of quite the same nature 

 as that of the corresponding sexes of the yellow clover {Colias fhllo- 

 dice)^ differing only in the greater speed and strength. Unless one 

 is well acquainted with it, this butterfly is not always easy to dis- 

 tinguish on the wing from the very large males of the yellow clover, 

 which are occasionally found here in the late summer. 



In the District the giant sulphur is wary and suspicious. It is 

 usually seen coursing rapidly along in a slightly zigzag or almost 

 straight line 5 or 6 feet above the ground. If there is any move- 

 ment of the air it always flies against the wind. More rarely it is seen 

 quartering the fields as it does in the regions permanently inhabited 

 by it. This indicates that the majority of the individuals seen here 

 are strays or migrants. 



Like many other butterflies, especially other pierids, the giant 

 sulphur seems to acquire a feeling of confidence with increase in 

 numbers, for where it is abundant it is as a rule not at all shy, though 

 easily frightened. 



It is very fond of flowers, especially yellow flowers, and also of 

 carrion and filth, and when feeding it is quite unsuspicious. It is 

 also fond of sucking moisture from mud, and where it is common 

 large companies are sometimes seen sitting quietly on muddy spots. 



Like its relatives in South America and in the Tropics of the Old 

 World, it is very easily decoyed by imitation butterflies cut out of 

 yellow paper and set up in muddy spots. In Tennessee I have 

 caught it in quantities by the use of such decoys. 



Genus ANTHOCHARIS Boisduval 



ANTHOCHARIS GENUTIA (Fabricius) 



Orange Tip 

 Plate 29, Figures 1 to 4 



Occurrence. — Frequent, but never very common, in moist open 

 deciduous woods. It is most numerous in the woods along Paint 

 Branch, and is also found in some numbers in the woods along the 

 river and the canal, in portions of Rock Creek Park, and elsewhere. 

 At the height of the season from 5 to 10 may be taken in a day in 

 the localities where it is most common. 



The Schonborn collection contains four males, four females, and 

 a pupa. The males were taken April 18 and 20, and the females 



