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. araucdrice, 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 agrifolia. 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. azdlece, 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 



