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. Californica. Sonoma Co., Cal., 1912. 
2 Day’s Deposit Date of 
eaaee —-| 1st Day’s 
Mose) Oe eas Seay eee 
Be epee poke fC ap Oe Es BE CE LO 5-25 
Bein pA Bee © Ge bate be be > Se ee bf 5-28 
OR ae £3 a de fede Bef a0 6-1 
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 
