The Influence of Climate in Producing Aberrations in 

 Lepidoptera 1 



By George Franck 



Since the beginning of the study of insects, or since entomology 

 became a factor in science, the question of variation and aberra- 

 tion in insects has been a matter of vital interest to entomologists. 

 Many volumes have been written in exploitation of various 

 theories and the question is still debatable. Some of these 

 theories are partly substantiated by' experimental evidence, gained 

 through the researches of certain eminent entomologists, fore- 

 most among whom is Dr. Standfuss, of Switzerland, who, through 

 his valuable experiments, has proven his theories to have the 

 foundation of facts. 



The ideas and theories advanced have resulted in two schools 

 or factions. One school adopts the theory that variations and 

 aberrations are dependent on the food plant or the influence of 

 some abnormal condition in the food plant, and supports it by 

 some evidence. The second attributes variations and aberrations 

 to atmospheric and climatic influences and this hypothesis seems 

 to be better supported, at least in so far as practical results count 

 in substantiating a theory. 



This article is intended to interest our own entomologists in 

 experimental study, to induce a freer record of their own obser- 

 vations, and to encourage any inclination to clear up this mystery. 

 For illustration I may cite some experiments carried out by promi- 

 ment entomologists of the Old World, since comparatively little 

 has been done in this country to solve this question. Mention 

 should, however, be made of Dr. O. Seifert, and of Prof. Wil- 

 liam M. Wheeler, now of the Bussey Institution. 



Referring again to the school which endeavors to prove that 



1 Read before Section of Biology, February 13, 1909. 



151 



