180 RECORDS. 



A, G. Mayer, The Instincts of Lepidoptera. 

 H. E, Crampton, Variation and Reproductive Selection 

 IN Saturxid Moths. 



Summary of Papers. 



Dr. Mayer's paper was a mere preliminary account of cer- 

 tain observations made by the writer. It is planned that the 

 research will be continued and finally published conjointly with 

 Miss Caroline G. Soule. Certain lepidopterous larvae, such as 

 Danais plexippiis, are negatively geotactic and positively photo- 

 tactic toward the ultra-violet rays. The combination of these 

 reactions in nature maintains the larva at or near the top of its 

 food plant, where incidentally it finds the youngest and best 

 leaves, and tends to prevent its crawling down and away from 

 the plant, thus incurring risk of starvation. Other larvae, such 

 as Pyrrliarctia Isabella, are indifferent either to the attraction of 

 gravitation or to ordinary variation in conditions of light. Others 

 react differently at different stages of development. Larvae which 

 will devour only certain definite species of leaves may be induced 

 to eat sparingly of an)^ other sort, provided the instinct to eat be 

 first set into operation by the presence of the proper food plant. 

 Under such conditions about the same number of bites are taken 

 upon each presentation of the uneatable food to the larva. This 

 phenomenon may be called " momentum of the reaction " and 

 inclines one to conclude that the eating reaction is probably an 

 unconscious reflex. Another series of experiments appeared to 

 show that larvae are unable to learn to follow a definite path to 

 their food, and that the associative memory of lepidopterous 

 larvae does not endure for as long a time as ninety seconds. 

 Certain larvae when about to pupate display a well-marked 

 geotropism. 



The mating instinct is called into play by the perception of 

 the characteristic odor of the female, and is merely a phe- 

 nomenon of chemotaxis uncomplicated by aesthetic appreciation 

 or sexual selection on the part of the female. 



Professor Crampton described briefly the principal results of a 

 statistical study of the correlation between structural character- 



