Centrifugal Force upon Beetles' Eggs 

 Series C.L. i — Table IX 



535 



The effects of centrifugal force upon the eggs of C. lunata when 

 oriented with their anterior ends toward the center are shown by 

 these experiments. 



C.L. I, a. The control egg of this series proved to be in a stage 

 similar to that already described for C. B. 9, a. 



C.L. I, b. After being centrifuged for twelve hours this egg 

 showed the customary three strata. Longitudinal sections resem- 

 ble those of C. M. I (Fig. 20); they differ from them only in the 

 absence of a well-defined blastoderm in the inner region. 



C.L. I, c. During the twenty-four hours since this egg was 

 taken from the centrifugal machine the yolk has had time to 

 redistribute itself to some extent and many of the larger globules 

 are present at the lighter end. Development has proceeded and 

 the inner half of the egg is one large syncytium in the center of 

 which is the vesicular zone containing a few nuclei. 



C.L. 7, d. Sections of this egg may be compared with that 

 of C.B. 9, ^, shown in Fig. 16. There is a mass of tissue at the 

 inner end which is thrown up into folds, but no definite structures 

 are distinguishable in it. 



C.L. 7, e. The only egg that was allowed to develop through- 

 out the entire hatching period produced a larva at the end of six 

 days. This larva is apparently normal. It was preserved when 

 three days old. 



TABLE X 



Leptinotarsa decemlineata — Series L. D. I 



