66 



Trans. Acad. Sci. of St. Louis. 



SAMIA CALIFORNICA. 



We could note the period of incubation of the ova of 

 only 3 members of this species. (See Table 42.) 



TABLE 42. 

 Period of Incubation. Eggs of 8. Calif ornica. Sonoma Co., Cal., 1912. 



Here the period of incubation was from 10 to 12 days 

 for eggs deposited between May 25 and June 5. 



PHILOSAMIA CYNTHIA. 



We submit below the data on the period of incubation 

 of the eggs of Cynthias from New York and Philadelphia. 

 (See Table 43, 44, 45.) 



The New York Cynthias emerged and oviposited 

 earlier than those from Philadelphia. If we compare 

 Tables 43 and 44 a little more closely we will observe 

 that all of the eggs in which the period of incubation 

 was from 10 to 12 days are at the top of the table, or 

 among the eggs deposited June 3 to 12. Again when 

 we look for the eggs which required only 8 or 9 days, 

 we find them under the dates June 13 to 20. Now this 

 first lot spent a period in development from June 3 to 

 28 inclusive, and the mean temperature for this period 

 of 21 days was 75.8° F. The eggs of the latter lot were in 

 incubation from June 13 to 29, for which period the mean 

 temperature was 83°. 



Hence in the Cynthias, as in all the other species here 



