294 University of California Publications. [Entomology 



The proportion of days upon which eggs were actually deposited 

 was found not to have any direct bearing upon the comparative 

 totals, the individuals of Olla oculata averaging 89.3 per cent 

 as compared with Hippodamia convergcns at 63.8 per cent, even 

 though the final total laid was in favor of the latter by a margin 

 of 48 eggs. The maximum proportion of days in which eggs 

 were deposited by a single individual was 95.5, this also being 

 to the credit of 0. oculata. The minimum was 28.0 per cent in 

 the case of H. convergcns. 



Periods of Oviposition 



Number 

 specimens 



C. californiea 10 



C. trifasciata 10 



H. eoiivergens 11 



H. ambigua 8 



O. abdominalis 9 



O. oculata 9 



A. bipunctata 10 



C. sanguiuea 10 



Rate of Oviposition. — A very considerable difference was 

 found to exist in the number of eggs deposited by the various 

 species. As would be expected from field observations, several 

 individuals of Hippodamia convergcns deposited a considerably 

 larger number of eggs than those of any other species, the maxi- 

 mum number secured from one female being 609 as compared 

 with 489 from Olla oculata, the next highest. This difference, 

 however, was not found to hold in regard to the general averages 

 of all individuals of each species, inasmuch as 0. oculata ranked 

 first with 347, Hippodamia ambigua second with 312, and H. con- 

 vergens third, with an average of 299 eggs for the full period. 

 As regards the maximum number of eggs deposited in one day, it 

 will be seen that H. convergcns leads with 43, Coccinella trifas- 

 ciata second with 31, and 0. oculata last with 22 in one day. 



Olla oculata ranks first in respect to the daily average for the 

 entire period of oviposition, with 9.8 eggs per day, while the 

 lowest average is 6.3 eggs per day in the case of 0. abdominalis. 

 General observations lead one to believe that H. convergcns under 

 field conditions is far more prolific than any of the other species. 



