[NSECT ENEMIES OF CITRUS FRUITS. 
13 
a month later inspections were made throughout the lower San Gabriel 
Valley, at Pomona, Ontario, and Riverside, and in Orange County. 
Throughout this valley a large majority of the young insects \\ hich had 
hatched were dead at this time while fully 50 per cent of the eggs had 
dried up. At Pomona, Ontario, and Riverside almost all the young 
insects had been destroyed, and fully 90 per cent of the eggs beneath 
the old scales. In Orange County Dear the coast a very small per- 
centage of eggs was affected by this hot period, while recently hatched 
young scales were much in evidence. The black scale occurs on a 
wide range of hosts, including trees, shrubs, and herbaceous plants. 
The red scale (fig. 5) thrives exceedingly well in the drier interior 
regions of southern California. Jt can be found within a few miles 
Fig. 
■Leaves and branch of orange infested with red scale (Chrijsompfialusauranti/). (Original.) 
of the ocean or as far inland as Redlands. The limits of its distri- 
bution are much the same as for the black scale. This species can 
be found on several host plants other than citrus species. 
The yellow scale is even more of a heat-withstanding form than 
the red scale. Infestation by this insect appears to be most marked 
in the foothills region of the San Gabriel Valley, and along the Sierra 
Madre Range through Upland and ( ucamonga, It is also broadly dis- 
tributed at Redlands, where it has become a more serious menace than 
elsewhere in southern California. That it is capable of withstanding 
excessive heat is demonstrated by its prevalence in citrus orchards 
in the San Joaquin Valley, at Marysville, Oroville, and other parts of 
the hot interior valleys of northern California, where the purple scale 
and to a large extent the black scale appear unable to survive. 
