Xo. 4.] 



SCALK INSECTS. 



43.^ 



at wliu'h to fix thciuselvcs. The}' then settle down and 

 plunge their beaks into the bark to the sap and begin to 

 feed. A covering scale is soon formed, protecting the insect 

 beneath, and in the fall the eggs are de})osited there, after 

 which the insect dies. There appears to be but one brood 

 each year in Massachusetts. 



This scale has quite a list of food i)lants, including tlu? 

 apple, pear, plum, (juince, pojjlar, willow, ash, lilac and 

 elm. Individual trees are frequently killed by it, but it is 



Fig. 3. — Oyster shell scale : o, under side of female scale, showing eggs ; b, upper side 

 of same, both nui(;h enlarged; c, female scales ou a iM-anch, natural size; <f, male scale, 

 much enlarged; e, male scales ou branch, natural size. The Hue Hues to the right of a, 

 b and rf show the real length of the scales. (Howard, U. S. Dept. Agr., Yearbook, 1894.) 



very rare that it spreads to the trees and shrubs around, 

 killing them all, as is so often the case with the San Jose 

 scale. It has enemies and parasites which aid in keeping it 

 in check, and its low annual rate of increase renders it much 

 less to be feared than the last-named pest. 



