New York Agricultural Experiment Station. 413^ 



History. — But little is known of the early history of this spe- 

 cies. According to our best authorities it is undoubtedly of 

 European origin but was introduced very early into this country. 

 It was first described in 173S by a Frenchman named Reaumer 

 who found specimens on an elm in his native country. Accord- 

 ing to Dr. Howard* it was known in this country as early as 1794. 



The earliest account which we have seen relating to the insect 

 in this State was published by Dr. Asa Fitch in 1856 in his first 

 report as State Entomologist (p. 31). Dr. Fitch states that the 

 insect was then known " everywhere through the northern states 

 . . . infesting the orchards to a grievous extent, causing the 

 death of many trees and impairing the health and vigor of many 

 more." The same writer quotes a Wisconsin correspondent who 

 states that the insect was evidently introduced into Wisconsin as 

 early as 1840. It is thus shown that the species had a wide 

 distribution in this country at an early date. 



Present distribution. — The oyster-shell bark-louse is known all 

 over the world. It occurs in more or less abundance wherever 

 apples and pears are grown. In the United States it is reported 

 from Maine to California, although it is not so well known in 

 many of the western states as in the east and south. It is widely 

 distributed throughout this State. While we are receiving speci- 

 mens from new localities every year, up to the present time speci- 

 mens have been received from the following counties: Erie, 

 Niagara, Monroe, Wayne, Ontario, Yates, Schuyler, Seneca, 

 Cayuga, Onondaga, Cortland, Jefferson, Lewis, St. Lawrence, 

 Columbia, Kings, Queens and Suffolk. 



Food plants. — The list of food plants for this insect includes a 

 large number of our common trees and shrubs. In the nursery 

 it is especially abundant upon fruit trees, such as apple and pear, 

 but it should be watched for on other stock such as currant, 

 gooseberry, blackberry and raspberry, also on ornamentals such 

 as maple, birofbi, elm and lilac. 



Descriptions and life history. — The life history of the oyster- 

 shell bark-louse is very similar to that of many other species of 

 scale insects. If an infested tree is examined in the winter the 



•Year Book U. S. Dept. Agr. 1894, p. 255. 



