INJURIOUS AND BENEFICIAL INSECTS OF CALIFORNIA. 



Ill 



about j 3 ^ inch. The color is gray, due to a mottled effect of dark 

 markings on the yellow bodies. Fig. 121 shows well the color pattern. 

 The young are first dark, or almost colorless, but gradually assume the 



color of the adults as they 

 mature. The eggs are 

 small, slightly oblong and 

 transparent or yellowish. 



Life History.— Matur- 

 ity is reached in April 

 and May and egg-laying 

 begins the last of April 

 and continues until the 

 middle or last of June. 

 Practically all of the 

 young are hatched by the 

 middle of July. The eggs 

 either hatch as soon as 

 laid or immediately after- 

 wards. It is sometimes 

 very difficult to find eggs 

 at all and it appears that 

 some of the eggs hatch 

 within the body of the 

 females and the young 

 are born alive. The young 

 usually settle along the 

 midribs of the leaves or 

 upon the very tender 

 twigs, where many remain 

 until m a t u r e. Others 

 move to the branches and 

 may be so thick as to over- 

 lap and completely hide 

 limbs as large as one half 

 inch in diameter. There 

 is apparently but one 

 uneven brood a year. 

 Nature of Work. — Although the leaves and petioles are generally 

 infested, the twigs appear to be preferred by this scale and old trees 

 are often very seriously attacked. This is in marked contrast to the 

 habits of the soft brown scale, which prefers trees under six years 

 of age, and then attacks principally the tender shoots and leaves. 

 The maturing forms secrete quantities of honey-dew and cause severe 

 smutting of the foliage and fruit. The trees are also greatly weakened 

 by their attacks and their bearing capacities greatly lowered. In fact, 

 this has proven to be one of the most serious of the citrus scale insects. 

 Distribution.— The distribution of this scale is quite large and new 

 districts are constantly being reported. At the present time it has 

 been found in the following counties : Orange, Los Angeles, San Ber- 

 nardino, Riverside, Kern, Fresno, Tulare, Contra Costa, Solano, Placer, 

 Tehama. Sacramento, Sutter, Yuba, Butte and Glenn. 



Fig. 120. — The gray citrus scale. Coccus citricola 

 Campbell. Overwintering young on an orange leaf. 

 Enlarged twice. (Original) 



