10 HYDROCYANIC-ACID GAS FUMIGATION IN CALIFORNIA. 
THE YELLOW SCALE. 
(Chrysomphalus citrinus Coq.) 
Infestations of the yellow scale appear to be most marked in the 
foothills region of the San Gabriel Valley and along the Sierra Madre 
Range through Upland and Cucamonga. It causes considerable dam- 
age at Redlands. San Bernardino County, yet elsewhere is not 
regarded as a very serious pest. This insect infests the leaves and 
fruit, seldom occurring on the branches. The young are born alive. 
as in the case of the red scale, to which it is closely related. 
THE MEALY BUG. 
(Pstudoeoeeus citri Ris? 
The mealy bug occurs in various sections of the southern part of 
California. The districts of greatest injury are in southern San Diego 
County and at Santa Paula, in Ventura County. Little effort for its 
control has been made except in these two places. This insect at- 
tacks fruit, leaves, and branches, secreting a honeydew. which is fol- 
lowed by a black fungus, as in the case of the black scale. Its injury 
is much greater than that of the black scale because it discolors and 
weakens the rind of the fruit at those places where it extracts the 
juice. The cottony secretion in which the eggs are deposited is 
difficult to remove. The severe washing which this fruit requires, 
combined with its weakened rind in certain places, produces a heavy 
decay in such fruits as are treated in this manner. The mealy bug 
occurs on several hosts beside citrus trees. The young are hatched 
from eggs deposited by the adult. 
APPARATUS. 
TEXTS. 
When hvdrocvanic-acid o-as was first emploved in treating orchards 
the apparatus used in the process was of a very cumbersome nature. 1 
The most popular apparatus consisted of tents more or less of a bell- 
shaped nature manipulated by a high derrick mounted on a wagon. 
The wagon was drawn between the rows and the tents lowered over 
or raised from the trees by means of ropes attached to the derricks. 
The use of such apparatus was difficult, slow, and costly. 
SHEET TEXTS. 
During 1892 Mr. C. W. Finch, a furnigator at Riverside. Cal.. 
devised a much simpler and cheaper apparatus than those theretofore 
used, which consisted of flat sheet tents, octagonal in outline. (Fig. 7. 
]>. 29.) This simplified tent was rapidly adopted, and now sheet 
rt of Entomologist, U. S. Pep:. Agr., 387, ; L26. 
