THE TRIBE OF THE YELLOWS 107 



delicacy of structure, one would have a pretty good idea 

 of the beautiful little creature called by the above name. 

 I well remember in my college days taking what was prob- 

 ably the first of these butterflies ever collected in the re- 

 gion of our Michigan college. It was a prize that very 

 likely had wandered north from Indiana but which served 

 to add much glory to the little collection in which I took 

 such pride, for this is essentially a southern species 

 In many regions of the South it is so abundant that it 

 can be taken by any one. It ranges from coast to coast 

 and extends south into the tropics. In the eastern region 

 it is found from southern Wisconsin to southern New 

 England, occurring sparingly and locally in various places 

 along the line thus indicated. 



The food plant of the species is chiefly wild senna or 

 other kinds of Cassia. The mother butterflies deposit 

 the eggs singly on leaves or stems, generally on the small 

 leaflets of the compound leaf. Less than a week later 

 each egg hatches into a cylindrical greenish caterpillar 

 that feeds upon the leaflets in a characteristic fashion. 

 Instead of devouring the blade from the margin inward it 

 gnaws narrow strips between the smaller veins. When not 

 feeding, the caterpillars protect themselves from observa- 

 tion by birds or other enemies by resting motionless along 

 the stem of the leaflet or else along the midrib on the under 

 side. As is well known the leaflets of Cassia, like other 

 leguminous plants, close at night. It is probably on this 

 account that these caterpillars feed chiefly by day. The 

 general green color of the skin and the straight stripe along 

 the side help to make this caterpillar very inconspicuous 

 when it is at rest. 



When full grown the caterpillar reaches a length of three 



