50 



BULLETIN 351, TJ. S. DEPARTMENT OF AGRICULTURE. 



Alto, Pa., during the winter of 1912-13 passed this period with a 

 mortality of less than 10 per cent. At Midvale, Pa., during the winter 

 of 1913-14, specimens upon poorly nourished trees had a mortality 

 as high as 54 per cent. Neither birds nor other animals make a 

 noticeable attack during hibernation, but there is a strong parasitic 

 attack upon the young females before hibernation. This was espe- 

 cially noticeable during the first week hi September. 



development of the male. 



Male Larva, Second Instar. 



In this instar the elongation of the larva and the secretion of the 

 puparium undoubtedly start immediately after the first molt, but 

 it is usually five or six days before they can be detected. The male 

 increases, as is shown in Table XXX, from an average length of 1.03 

 mm. to an average length of about 1.706 mm., and in width from an 

 average of 0.421 mm. to an average of about 0.*830 mm. There is 

 also an appreciable increase in height. 



Table XXX.' — Average measurements of the male terrapin scale in the second instar at 

 various ages between the twenty-fifth and thirty-fourth days, at Mont Alto, Pa. 



Year. 



Date 



emerged. 



Age. 



Number 

 of speci- 

 mens. 



Average 

 length. 



Average 

 width. 



1912 

 19i2 

 19i3 

 1912 

 T913 

 1913 

 1913 



Aug. 9 



...do 



June 24 

 Aug. 9 



June 26 

 June 24 

 ...do 



Days. 

 25 

 26 

 30 

 31 

 32 

 33 

 34 



1 



2 

 14 



4 



13 

 13 



8 



Mm. 



1.031 

 1.218 

 1.628 

 1.579 

 1.661 

 1.621 

 1.706 



Mm. 



0.468 

 .421 

 .830 

 .642 

 .809 

 .813 

 .777 



In 1912 the instar extended to the fortieth day, but practically 

 all males had shrunk in preparation for the second molt by the 

 thirty-fifth day. 



The following table compares the measurements of 54 females in 

 the second instar with 48 males of the same rearing, and shows that 

 the females average 0.168 mm. wider and 0.111 mm. shorter than the 

 males. 



Table XXXI. — Comparative measurements of male and female larvx of the terrapin scale 

 during the second instar. Mont Alto, Pa. 



Age. 



Date 



emerged. 



Number 

 males. 



Length 



of 

 males. 



Width 



of 

 males. 



Number 



of 

 females. 



Length 



of 

 females. 



Width 



of 

 females. 



Days. 

 30 

 32 

 33 

 34 



June 24 

 June 26 

 June 24 

 ...do 



Total.... 

 Average. 



14 

 13 

 13 



8 



Mm. 



1.62S 

 1.661 

 1.621 

 1.706 



Mm. 



0.830 

 .809 

 .813 



. 777 



16 

 20 

 11 



Mm. 



1.507 

 1.506 

 1.587 

 1. 575 



Mm. 



0.982 

 .937 

 .978 



1.012 



48 





54 







1.654 



.807 







1.543 



.975 









