Explanation of Plate Y. 



Fig. 1, the San Jose scale, Aspidiotus pevniciosus Gomstock, infesting a pear 

 twig; 2, the scales. on a leaf; 3, scattered scales on a pear; 4, a female 

 scale, enlarged; 5, a male scale, enlarged. (From the Cornell Uni- 

 versity Agr. Exper. Station, and by permission of the California 

 State Board of Horticulture.) 



