44 



MASS. EXPERIMENT STATION BULLETIN 157 



jected. In fact, the greater number of this lot were the pupse of the larvse 

 which were followed in the insectary for the purpose of determining the 

 length of the larval period. The remaining 63 developed during the last 

 daj^s of February -and the first part of March, and, like their larvse, in the 

 room adjoining the insectary, where the temperature was markedly 

 higher than in the insectary. 



Table III. — Length of the Pupal Period of 134 Pupos which developed in 

 the Insectary during November, at a Temperature of about 55° at Night 

 and of about 65° to 70° during the Day. {See Temperature in Con- 

 nection with Length of Egg Stage.) 



Number ofIPup^. 



2. 

 2, 



27, 

 18, 

 47, 



I^ength 



of Pupal 



Period 



(Days). 



12 



121/^ 

 13 



13}-^ 

 14 



NUMBEH OF PUP.E. 



15, 



20, 



2, 



1, 



Length 



of Pupal 



Period 



(Days). 



14J^ 

 15 



15J.-^ 

 16 



It is thus seen that the length of the pupal period also varies independ- 

 ently of the temperature. The variation, however, it should be noted, is 

 less than among the larv£B, as might be expected, especially among the 

 larvae which, like the pupse, developed in the insectary, and with which 

 they should more properly be compared. It should also be noted that a 

 period of from thirteen to fifteen days, inclusive, embraces the great 

 majority, indeed, almost all. 



Table IV. — Length of the Pupal Period of 63 Pupce in the Room adjoining 

 the Insectary, during February and March, at a Temperature, on the 

 Whole, much Higher than that in the Insectary during November. 



Number of Pup^. 



7, 



1, 



19, 



3, 



Length 



of Pupal 



Period 



(Days). 



8H 



9 



9H 



Number of Pup.e. 



26, 

 1, 

 3, 



Length 



of Pupal 



Period 



(Days). 



10 



WA 

 11 



12 



A comparison of the two tables will show at once the difference in the 

 lengths of the pupal periods of the two lots of pupse, due to the difference 



