Seasonal Changes 



of various naturalists when some axolotls which were 

 kept in the Jardin des Plantes in Paris, finding their 

 water supply was running short, turned into amblystomas. 

 Then and then only was it discovered that the creatures 

 were one and the same, that the axolotl is simply the 

 larval form of the amblystoma, but withal a larval form 

 which has so far developed that it can reproduce its kind, 

 an event which is impossible in the case of the tadpoles. 



The seasonal changes in certain tropical butterflies are 

 very marked and very remarkable, as a study of this species 

 in any good museum will show. That tropical insects 

 should have summer and winter forms is as remarkable 

 as is the difference between these forms. One explanation, 

 and a plausible one, is that the changes are due to the 

 still surviving efforts of the glacial epoch. During this 

 epoch there was perhaps only one form the winter form. 

 Change of climate then produced the summer form. 

 In this connection it is interesting to note that by keeping 

 the chrysalids of these butterflies which should develop 

 into summer forms in artificial cold, they will emerge as 

 winter forms. 



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