DISCUSSION OF GENERA AND SPECIES 



35 



very sporadic in its occurrence. The poison oak is one of our most 

 abundant shrubs, yet I have met with the scale but twice, each time on 

 isolated bushes and here in abundance. It is presumably native. 



In all of the specimens examined the derm of the fully mature female 

 is entirely membranous. The marginal spines (Fig. 155) are slender 



Fig. 15. Pulvinaria rhois Ehrh. : A, antenna; B, marginal spines in the region of a 

 stigmatic depression ; C, anal plates, dorsal aspect left, ventral aspect right ; 

 D, tarsus and portion of tibia. From specimen from topotype material. 



and quite long and are arranged in an irregularly single or double series. 

 The stigmatic spines are large and conspicuous, the median spine being 

 nearly three times as long as the others. Anal plates (Fig. 15C) quite 

 large and broad, each with three or four apical setae on the dorsal side 

 and two subapical setse on the ventral side. Antennae (Fig. 15 A) nor- 

 mally 8-segmented. Legs rather stout, the claw (Fig. 15D) with very 

 broad digitules. 



