1911] 



Notes on the Colorado Potato Beetle 



7:; 



TABLE I. 

 Duration of the Egg Stadium, Urbana, III., Season 1908. 



But first attention should be drawn to the fact that there 

 exists variation in the duration of embryonic development for 

 batches of eggs deposited at the same time, hence subject to the 

 same environmental factors including temperatures. Thus in 

 lots 13 and 14 (Table 1), from different parents, deposited at 

 the same time on June 14 hatched at different times on June 

 19, lot 14 hatching 13 hours earlier than lot 13. And in 

 lots 8 and 9; although there is a difference of an hour and a half 

 between the times of deposition, the times of hatching diverge 

 still more being separated by four hours and the lot deposited 

 last hatched first. These lots were from the same parent. But 

 contrary to this, in lots 10 and 11 deposited by different parents 

 within 45 minutes of each other, the lot deposited first hatched 

 first, the times of hatching being 14f hours apart. However, 

 lots 20 and 21 deposited by different parents at the same time 

 hatched within an hour of each other. The data are insufficient 

 but parentage apparently does not account for the variation 

 between batches of eggs deposited simultaneously and we must 

 state tentatively that it is inherent and hence subject to the 

 laws of chance or else there are factors involved which have 

 escaped detection. We think this variation is inherent and 



