THE TERRAPIN SCALE. 



49 



appears at its worst upon varieties that ripen after September 1. A 



basket of sooty peaches, with two normal peaches for comparison, is 



shown in figure 16. 



Hibernation. 



The scales depend for protection during hibernation upon their 

 protective coloration, their hard derm, and their waxy coating. 

 The color, while conspicuous in detached specimens, blends so nicely 

 with the color of the young twigs as to conceal them effectively. 

 The hard derm protects them from birds and insect enemies, and 

 the wax film protects the insect from rain, surface moisture, and 

 scalecides by prevent- 

 ing their passing un- 

 der the scale. 



SIZE DURING HIBERNATION. 



Eulecanium nigro- 

 fasciatum passes the 

 winter as an impreg- 

 nated female. The 

 following measure- 

 ments, which were ta- 

 ken from fresh speci- 

 mens at Mont Alto, 

 Pa., February 24, 

 1913, are typical for 

 the hibernation 

 period: Length, maxi- 

 mum 2.375 mm., mini- 

 mum 1.80 mm., aver- 

 age 2.072 mm. ; width, maximum 2.28 mm., minimum 1.79 mm., aver- 

 age 2.0308 mm.; height, maximum 1.1 mm., minimum 0.725 mm., 

 average 0.9084 mm. 



POSITION ON TWIGS DURING HIBERNATION. 



This species when on peach locates exclusively upon the last three 

 seasons' growth, and by far the largest number of specimens is found 

 upon the earliest formed wood of the last growing season. (See 

 PI. Ill, figs. 1, 2.) 



The females in 1912 continued more or less active until November 

 12, and they remained dormant until April. This made the hiber- 

 nating period cover about 4J> months. 



MORTALITY DURING HIBERNATION. 



Practically every normal female will pass the hibernation period 

 safely unless some accident happens to the host. Specimens at Mont 

 20782°— Bull. 351—16 -4 



Fig. 16. — A basket of "sooty" peaches with two clean ones for con- 

 trast. (Original.) 



