6 The Bulletin. 



lives of many trees, since the owner, instead of examining closely and 

 treating every infested tree, as lie should do, simply takes out those which 

 are already in dying condition, and then, because he sees no more of simi- 

 lar appearance, he imagines he has exterminated it, when as a matter of 

 fact other trees moderately or slightly infested still stand in the orchard 

 and soon begin to die, having in the meantime spread the insect into still 

 other trees, and so on, until the whole orchard may be ruined. 



"Where the scales are not numerous enough to crowd one another each 

 individual grows to somewhat larger size than when they are crowded. 



a 



Fig. 1.— the SAN JOSE SCALE. 



a. Appearance of infested twig, natural size. b. Part of infested twig, as seen 



under a lens. 



(After Howard and Marlett, U. S. Department of Agriculture.) 



Where the scales are scattered along the branches each scale is often 

 (but not always) in the center of a slightly reddened spot on the bark. 

 If the natural color of the bark be reddish this spot will not show plainly, 

 but if the bark be of a light green or yellow, the reddish spots are quite 

 conspicuous. In looMng for scale on slightly infested trees it may usually 

 he more readily found hy looking for these reddish spots than by looking 

 for the scale itself, hut close watch must he kept for both scales and 



