OBSCURE SCALE ON THE PECAN AND ITS CONTROL 7 



which it settles in the formation of its cover and by this use blend itself 

 into the coloration of the surrounding bark surface. In figure 6 is 

 shown the light appearance of the scale covers on a light-colored bark. 

 The first molt begins about 5 to 6 weeks after settlement, and sec- 

 ond-stage larvae appear about 1 week later. By the middle of Sep- 

 tember practically all normally developing specimens (about 50 to 60 

 percent of all that settle) have reached this stage. No other change 

 in development is to be noted save for a gradual increase in size until 



Figure 6. 



A group of individuals of the obscure scale on a very light-colored bark, 

 the scales shown in figure 2. X 12. 



Compare these with 



about the middle of October, when some of the males can be distin- 

 guished from the females for the first time. From this point devel- 

 opment of the two sexes proceeds along different lines. 



The females continue to increase in size until about the first of 

 December, when the older ones begin to enter the stage preparatory 

 to the second molt, followed shortly by the remainder, with practi- 

 cally all specimens completing the change by the last of January. The 

 females remain in this stage until development into the adult stage 



