1 90 



PHINEAS W. WHITING. 



of the prepupal period as in the case of IQI2-/. My only explana- 

 tion for this is that the temperature being higher in August than 

 in November, drying out had been more rapid at the former time 

 and thus a condition was reached in which the larvae had not 

 enough moisture to be able to pupate. This was supplied them 

 in the later steps of the experiment. 



The following experiment brings out another disturbing factor 

 which acts as an inhibitor to pupation. 



One hundred and seventy-six full-grown larvae were obtained 

 on December u, 1912, which were also progeny from the later 

 layings of the same L. sericata 9 , 1912- V. These were put into 

 very damp sand crowded in a glass jar and kept at room tempera- 

 ture. On December 27 it was found that only 36 had pupated. 

 The remaining 140 were distributed in five jars and their subse- 

 quent history is recorded in Table II. 



TABLE II. 



RECORD OF SECOND LOT OF PROGENY FROM L. sericala, 1912-^. 



From the delay in pupation from December II to December 

 27 it would appear that the crowding tended to inhibit pupation. 





