INJURIOUS AND BENEFICIAL INSECTS OF CALIFORNIA. 167 



Food Plants.— Arborvita?, Biola orientalis, incense cedar, common 

 juniper, cypress, Cupressus htsitanica. Juniper us chinensis, J. japon- 

 icus, J. oxycedrus, J. reresii, J. rigida and J. sph erica are among the 

 recorded hosts. 



Fig. 144. — The juniper scale, Diaspis carueli Targ., on Cu- 

 pressus lusitanica. Natural size. (Original) 



Control.— The application of crude oil or kerosene emulsions during 

 the winter will serve to check any damage. 



THE CACTUS SCALE 



Diaspis echinocacti cacti Comstock 

 (Fig. 145) 



Description.— The scales of the females are nearly circular, thin, 

 light gray or whitish with subcentral dark brown exuvias. The diameter 

 varies from -^ to 1-14 inch. The male scales are very small, slender, 

 white with a longitudinal carina in the middle. 



