22 Trans. Acad. Sci. of St. Louis. 



possible to make more extended observations. The 

 imagines were placed under the same climatic conditions 

 and were given an opportunity to mate as soon as possible 

 after hatching. The material proved to be good for just 

 such observations, as all the matured individuals of this 

 family have rudimentary mouth parts, and the Cecropia 

 moths take no food. 



The observations and notes were never made at greater 

 intervals than six hours; the last notes were made each 

 day near midnight, the first in the morning about six, 

 and during the day notes were made at intervals of about 

 three hours. The time upon which the tables are based 

 is the time when the notes were made, not the time when 

 the act (mating, hatching, dying, etc.) may have occurred. 

 This method is not mathematically exact, since it is impos- 

 sible to be present at the precise moment when the insects 

 mate or hatch or die. I think, however, that my figures - 

 are as exact as could possibly be obtained. The observa- 

 tions extended from the time when the first pair was seen 

 in copulo, May 16, 1909, until the death of the last male 

 on June 22, 1909. 



It gives me great pleasure to here acknowledge my in- 

 debtedness to Professor A. C. Eycleshymer of St. Louis 

 University and Professor J. F. Abbott of Washington 

 University for valuable suggestions in the preparation 

 of this paper. 



II. Observations on Life Cycle. 



1. DURATION OF LIFE OF MALE. 



(a) The duration of life of male from hatching until 

 death. 

 Notes derived from observations in six instances. In 

 the following tables the designations are for each copu- 

 lating pair: 



