SMITHSONIAN EXPLORATIONS, I928 



105 



winter is killed out apparently through dessication in the cold dry 

 winter air. Should our climate undergo a change and should we have 

 alternate seasons dry and wet as occur in India instead of a cold 

 winter with severe dry spells and a summer dry in some localities and 

 wet in others, our butterflies undoubtedly would adopt the regular 

 alternation of wet and dry season forms seen in their relatives in India. 

 Indeed, two other of our butterflies, the hop merchant {Polygonia 

 comma) and the question mark (Polygonia intcrrogationis), have a 

 light-colored, long-winged dry season form which appears late in the 

 summer, lives through the winter, and flies again in spring, and a 

 dark-colored, short-winged wet midsummer form. While the autumn 



Fig. 92. — Viceroy (Basilarcliia archippits) ; September 10, 1928. 



brood of these two butterflies is always exclusively of the light-colored, 

 long-winged dry season form, individuals of this form sometimes 

 occur in the summer brood. Besides, the light form is not so strongly 

 marked as it is further north. 



An extraordinary mixing of the different forms is seen in the 

 orange clover butterfly (Eurymus curythcnic) which, normally of 

 only casual occurrence, has for the past two years been extremely com- 

 mon. In northern Texas, as described by Boll, the first individuals to 

 appear are of the form called ariadnc, small and pale yellow with a 

 faint flush of orange on the lower part of the fore wings. The butter- 

 flies of the next brood (form kcezvaydin) are much larger, and the 

 orange is of a deeper and brighter tint and covers a much more 

 extensive area. The butterflies of the next two broods are large and 

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