32 



MASS. EXPERIMENT STATION BULLETIN 189. 



Pupal Period. 

 Pupation generally occurs within the tunnels made by the larva, 

 although occasionally it occurs in masses of larval frass, or between closely 

 attached leaves. The duration of the pupal period, in the instance of 

 49 individuals confined in life-history cages, averaged 8.5 days, with a 

 maximum of 10 and a minimum of 7 days, depending upon temperature 

 conditions (see Table IV). 



Table IV. — Duration of Pupal Period — First Generation. 



-Average length of pupal stage, ........ 8.551 days. 



Maximum length of pupal stage, 10 days. 



Minimum length of pupal stage 7 days. 



