DISCUSSION OF GENERA AND SPECIES 



45 



are always present in some degree of development about the bases of the 

 marginal spines. In all other respects D. piricola is a perfectly typical 

 species of Diaspis. As far as the unusual development of these thick- 

 enings is concerned the species is connected with typical Diaspis by such 

 a form as D. montana Ckll., in which there is an obvious tendency in the 

 same direction. 



Certain other species that have been ascribed to Epidiaspis should 

 probably likewise be referred to Diaspis. 



Diaspis carueli Targ. 



Very abundant on Libocedrus decurrens, Thuya sp. and various 

 species of Cupressus on the Stanford campus and doubtless elsewhere. 

 An introduced species. 



Diaspis echinocacti (Bouche). 



On various species of cacti on the Stanford University campus. An 

 introduced species. 



Diaspis manzanitae (Whitney). 



Fig. 21. 



I have found this species in but a single restricted locality, near 

 Summit Rock, above Saratoga, at an altitude of approximately 3000 feet, 

 where it occurs on the leaves of some species of Arctostaphylos. 



Fig. 21. Diaspis manzanitce (Whitney) : pygidium of specimen from Santa Cruz 



Peninsula. 



