1915] 



Hegner — Chrijsomelid Beetles 



25 



as they lay in the dishes regardless of whether this was the upper 

 or under surface in nature. 



A series of experiments were then performed in order to deter- 

 mine if direct sunlight is injurious to the developing eggs. These 

 experiments extended over the period from June 11 to June 23, 

 1914. Fortunately these days were practically cloudless and thus 

 afforded an abundant and uninterrupted supply of sunlight. The 

 details of two experiments will suffice to indicate the nature of 

 the experiments and the conclusions that may be drawn from them. 



Experiment I. 



On June 15, fifty batches of potato beetles' eggs were collected 

 at random. Each batch of eggs and that part of the leaf to which 

 it was attached was cut away from the rest of the leaf. Thirty- 

 five batches were then pinned firmly to a board and the board was 

 placed on top of the laboratory where the rays of the sun would 

 strike the eggs throughout the day. The remaining fifteen batches 

 were pinned to another board, which was placed beside the other 

 but inverted so that the eggs were in the shade at all times. The 

 results are recorded in Table I. 



Table I. 



As shown in the table all of the fifteen batches placed in the 

 shade under the board hatched. Their ages when collected differed 

 greatly since some of them hatched every day until all of the larvae 

 had emerged. Those that hatched on the seventh and eighth 

 days (June 22 and 23) must have been fresh when gathered, and 

 their hatching must have been delayed for some reason since the 

 normal hatching period is five to six days. Lack of moisture is 



