2 24 NEW YORK STATE MUSEUM 



RosacecB — (Continued) Cornacece 



Plum. Dogwood. 

 Cherry. Ebe?iacece. 



Spiraea. Persimmon {Diospyros). 



Raspberry. 



■r, Urticacece 



Kose. T-, 



Elm. 



Hawthorn (Cratces^us). r\ r\ 



^ * ' Osage Orange. 



Cotoneaster. 



June Berry. Juglatidacece 



Pear. English Walnut. 



Apple. Pecan Nut. 



Quince. 



Flowering Quince. BeiulacecB 



Alder? {Almis). 

 Saxift agacecB 



Gooseberry. Salicacecz 



Currant. Weeping Willow. 



Flowering Currant. Laurel-leaved Willow (from Asia). 



It will be seen from the above that the scale is recorded as occurring 

 on plants in eleven of the Orders, although one-half of the food-plants 

 named belong to the Order Rosacece. 



Spread of the Insects. 



The natural spread of this scale is not a rapid one. As the female is 

 unprovided with wings, and is unable to change its position after having 

 become fixed and throughout its entire period of reproduction, the insect 

 can only pass from one tree to another during the few hours that it con- 

 tinues in its active larval stage. Although a rather rapid traveler its 

 range of locomotion would hardly ever carry it to neighboring trees in 

 an orchard, unless the branches should interlock, in which case every 

 facility is afforded it for spreading the infestation — almost equal to that 

 existing in nurseries where the young trees are grown so closely together 

 as to form compact masses. 



Carried by birds, etc. — It has been found that the young insect may be 

 distributed through the agency of other insects and of birds. When 

 abounding on a tree to the extent that much of the bark is already occu- 

 pied by the scales, they apparently show a disposition to leave the tree 

 and fasten upon any visiting insect or to the legs of birds. If this is 

 instinctive or in accordance with a purpose, they will leave their hosts as 

 soon as transported to a favorable place for the establishment of a new 



