THE TREBE OF THE YELLOWS 103 



species. The resemblance is very remarkable and shows 

 the close affinity between these two beautiful insects. 



Like so many others of this group the Orange Sulphur 

 is essentially a tropical species. In the eastern United 

 States it is rarely found north of latitude forty degrees, 

 but south of that it becomes increasingly abundant as 

 one approaches the tropics. It occurs from the Carolinas 

 to Texas, and over the great range in which it lives it takes 

 on many different forms and habits. It is one of the most 

 remarkable examples of variation in coloring exhibited by 

 any of the butterflies. Nearly a dozen species names have 

 been given to its various disguises, all of which are now 

 recognized as synonyms. In the more northern regions 

 where it is found, only one of these forms usually occurs, 

 but in other places bright yellow and pale white varieties 

 are found. 



The life-history of this butterfly along latitude forty 

 degrees is very similar to that of the Clouded Sulphur. 

 There seem to be usually two broods and the caterpillars 

 live upon leguminous plants, especially alfalfa, buffalo 

 clovers, wild senna, and other species of Trifolium and 

 Cassia. Apparently also it hibernates in both the cater- 

 pillar and the butterfly stages. 



In the extreme Southwest — as on the plains of Texas — 

 the vegetation dries up completely in summer so that 

 there is no succulent leafage for the caterpillars to live 

 upon. In such cases the insect must aestivate rather than 

 hibernate. This species apparently succeeds in doing this 

 by having the caterpillars go into a more or less lethargic 

 condition in which they pass the summer. The adult 

 butterflies utterly disappear in June and are not seen 

 again until early in autumn when the autumn rains have' 



