254 PERIODICITY IN 



mer case, the scarcity may involve several species, 

 and the plain cause some excessive or exceptional 

 meteorological condition. 



Now though the massive meteorological condi- 

 tions which we term climate have undoubtedly 

 very much to do with the distribution of butter- 

 flies and determine, indeed, in very many cases, 

 whether or not a given kind shall or shall not live 

 in a certain place, the indirect results of mete- 

 orological conditions have undoubtedly more to do 

 with the abundance or scarcity of a given butterfly 

 in a given season. For the very existence of the 

 butterfly shows its capability of withstanding the 

 excesses of meteorological conditions in the spot 

 in which it lives, and the greatest stresses under 

 which it lives are those more active forces, like 

 insectivorous creatures and parasites, which find 

 their own life dependent on taking its life, or its 

 neighbor's. The activity of these is governed 

 largely by temperature and storm conditions, and 

 hence the indirect influence of meteorological con- 

 ditions on the life of the butterfly may be more 

 important than the direct. A caterpillar which 

 could withstand any amount of cold or of warmth 

 in itself considered might not be able to battle 

 against the foes which a mild winter kept in un- 

 usual activity and need of sustenance. It does 



