56 



BULLETIN 351, IT. S. DEPARTMENT OF AGRICULTURE. 



Table XXXIV.— Length of the pupal instar of the terrapin scale for larvx that emerged 

 June 24, 1913, Mont Alto, Pa. — Conditions favorable. 



Xo. 



Date 



entered. 



Date 

 left. 



Pupal 



stage. 



Xo. 



Date 

 entered. 



Date 

 left. 



Pupal 

 stage. 



1 



Aug. 2 



Aug. 10 

 Aug. 8 



...do 



Aug. 7 

 Aag. 8 



...do 



Aug. 5 

 Aug. 10 



Days. 



? 

 ? 



6 1 



4 



7 



9 



Aug. 2 

 Aug. 1 

 July 31 



...do 



Aug. 3 

 Aug. 1 



Aug. 9 

 Aug. 8 

 Aug. 5 

 Aug. 6 

 Aug. 8 

 Aug. 7 



Days. 



7 

 7 



2 



...do 



Aug. 1 



...do 



...do 



Aug. 2 

 Aug. 1 

 Aug. 3 



10 



3... 



11 







12 



13 



6 



6 



14 



6 









8 



6 2 









i 1 





APPEARANCE OF PUP^E IN THE ORCHARD. 



Pupae appear in the orchard upon the second day after the females 

 start migrating to the twigs, and they are most abundant about the 

 sixth day after the maximum daily migration. 



At Mont Alto, Pa., 80 per cent or more of the males pass through 

 the pupal state during the first half of August. 



SIZE OF prp.E. 



The pupae are slightly smaller than the prepupae, but owing to the 

 great size oi the wing-pads the pupa? average slightly wider. 



Table XXXV gives measurements for 20 specimens, the first 10 of 

 which were from 1912 and the remainder from 1913. The sizes are 

 quite uniform for the two seasons and average 1.248 mm. long and 

 0.5918 mm. wide. A comparison of the prepupal and pupal measure- 

 ments from the same individuals shows an average decrease in length 

 of 0.09 mm. and an increase of 0.03 mm. in width in passing into the 

 pupal instar. 



Table XXXV. — Measurements of 20 mature pupx of the terrapin scale, Mont Alto, Pa., 



1912 and 1913. 



NO. 



Length. 



Width. 



Xo. 



Length. 



Width. 



Xo. 



Length. 



Width. 



1 



Mm . 

 1.2250 

 1.3375 

 1.2750 

 1.3000 

 1.3000 

 1.2500 

 1.2500 

 1.2000 



Mm. 



0.55 

 . 575 

 .550 

 .600 

 .550 

 .600 

 .562 

 .625 



9 



Mm. 

 1.1000 

 1.2500 

 1.325 

 1.250 

 1.250 

 1.250 

 1.200 



Mm. 



0.600 

 .625 

 .625 

 .475 

 .650 

 .550 

 .600 



16 



Mm. 

 1.250 

 1.175 

 1.275 

 1.250 

 1.250 



- Mm. 



0.650 



2 



10 



17 





3 



11 



18... 



.650 



4 



12 



19 



.625 





13 



20 



.600 



6 



14 



Average... 







15 



1. 24S1 



.5918 



8 











Fourth Molt. 



The fourth molt, like the third, usually starts in the morning when 

 the temperature rises to about 70° F. The first indication that a 

 molt is about to start is a series of convulsive movements. These 

 cause the thin pupa case to split along the anterior third of the mid- 

 dorsal line. As these movements continue the dorsal thorax pro- 



