

OBSERVATIONS ON THE DURATION OF LIFE, ON 

 COPULATION AND ON OVIPOSITION IN 

 SAMIA CECROPIA, LINN.* 



Philip Rau. 

 I. Introduction. 



I became interested in Weismann's writings on the 

 duration of life in insects and was attracted by the appar- 

 ent opportunity of doing more work along these lines. In 

 the greater number of his citations it is not stated whether 

 the lives of both sexes, in any one species, be of equal or 

 of unequal lengths, and in but few instances does he give 

 any exact information on the duration of the life of the 

 male, or of the fertilized or the unfertilized female. 



I, therefore, decided to make further observations on 

 the duration of life in the male and also on the fertilized 

 and unfertilized female; on copulation and oviposition; 

 on the relation of the duration of life to perfect or imper- 

 fect oviposition; on the relation of time spent in copulo 

 to perfect or imperfect oviposition ; and on the relation of 

 ages of parents at the time of copulation to perfect -or 

 imperfect oviposition. 



The material selected for these observations was the 

 common Cecropia moth, Samia cecropia Linn. 



The cocoons, sixty-nine in number, were gathered early 

 in April, 1909, in the fields near the river Des Peres, just 

 south of Forest Park, St. Louis, Mo. They were placed in 

 wire cages (11 1/2 x 10 1/2 x 24 inches) and kept in an 

 outhouse to insure them against premature hatching. The 

 imagines emerged at intervals from May 14th to June 

 14th (forty-three males and twenty-five females) ; from 

 one cocoon none hatched, and none was parasitized. 



Notes were made on twelve copulating pairs and on 

 four unfertilized females. Lack of facilities made it im- 



* Read before the Entomological Section September 30, 1909, and pre- 

 sented by title to The Academy of Science of St. Louis, December 6, 

 1909. 



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