18 



BULLETIN 351, U, S. DEPARTMENT OF AGRICULTURE. 



The 1912 emergence was shortened by the drying of the twigs to 

 which the females were attached. This was due to the method of 

 isolation. This difficulty was overcome in the 1913 record. 



The larvse of Hijperaspis hinotata Say were more destructive in 1913 

 than in 1912, but on the whole both records are very true to the 

 conditions prevailing in the orchard during the respective seasons. 



For convenience in comparison and also to show the effect of 

 weather conditions upon this emergence, two graphs, figures 3 and 4, 



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Fig. 4.— Curve of the leafward migration of the terrapin scale for the total emergence period of 1913. 



(Original.) 



are appended. Figure 3 has a solid line added. This represents the 

 weather correction for the curve. In figure 4, where the curve is 

 determined from weekly observations, very little irregidarity, due to 

 the daily weather conditions, appears. 



The emergence period of 1913 was moderately favorable. The 

 temperature was high and the storms were of short duration. On 

 June 19, 22, and 26 rain checked the emergence, but the larvae 

 merely remained in the brood chambers over night and emerged on 

 the following day. 



The graph of total emergence by weeks during 1913 (fig. 4) shows 

 a very uniform curve. From the graph it appears that the major por- 

 tion of the young emerged during the first three weeks of the period. 



