140 



AN INTRODUCTION TO ENTOMOLOGY. 



vinaria, of the next sub-family. The egg-sac of Icerya, however, is 

 beautifully ribbed, while that of Pulvinaria is not of very definite 

 form. Icerya is an introduced insect from Australia. 



Rhizococcus. — Two species of Rhizococcus are figured on Plate IV. 

 Fig. i represents R. araucarice, a species infesting Norfolk Island 

 pine {Araucaria excelsior) in southern California; and Fig. 2 is of 

 R. quercus upon oak from Florida. This genus is a good illustration 



Fig. 126. — Kermes sp., on Quercus agri/olia. Adult females on stem ; immature males on leaves. 

 (From the Author's Report for 1880.) 



of the forms that spend a greater part of their lives within sacs. A 

 more common illustration of this occurs in the genus Eriococcus, of 

 which we have a species, E. azdlecc, common upon azaleas in con- 

 servatories. 



Kermes. — The most abnormal members of this sub-family consti- 

 tute the genus Kermes. Species of this genus are common upon 



