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Scales from Tahiti. 
The inclosed samples were taken from trees recently brought in from Tahiti. The 
large ones resemble the color of the bark, adhere very firmly, and are like Lecanium 
olew in resisting disinfectants, even hydrocyanic acid gas. These samples have all been 
subjected to the gas treatment and appear to be dead excepting the large round 
species which we are unable to name satisfactorily. On the fruit you will find two 
other varieties which do not appear on the tree except occasionally on foliage. * 
* * ([W.E. Collins, California, July 2, 1891. 
Reprty.—Three different scales were found upon the samples of twigs and fruit 
which were received recently from Tahiti. The large round species is Chionaspis 
biclavis Comstock, described originally from specimens found upon several imported 
plants in the greenhouse at the Department. It has never been found elsewhere 
before receipt of this specimen from you and its original habitat has always been in 
doubt for the reason that in our greenhouses it infests trees from several different 
localities. The narrow scale on both twigs and fruit belongs to the species known 
in Florida as the Purple Scale (Mytilaspis citricola), «a form which is now almost cos- 
mopolitan in its distribution. The round scale on the fruit is the common Red Scale 
(Aspidiotus aurantii). All these scales were dead on receipt except the Chionaspis. 
—[July 10, 1891.] 
Plant-louse on Celery. 
I send a sprig of celery from a garden near my office having upon it specimens of 
an Aphis which our hop-growers claim to be identical with the genuine Hop-louse. 
The patch of celery from which this was taken was nearly ruined by this louse last 
season, the insect working upon it from early in the autumn. Whether or not this 
is the Hop-louse, it is certain that the genuine hop pest has been seen from time to 
time all wintér upon the old vines and rubbish in some of the gardens, and our 
farmers say from the willows along the river banks. * * * [W. W. Corbett, 
Washington, March 4, 1891. 
Repity.—The insect is not the Hop-louse, but seems to be Aphis pastinaci, the 
common Parsnip Plant-louse. They were all dried or badly damaged, so that it is 
impossible to accurately determine them. * * * The supposed Hop-louse which 
you mention as having been seen on willows along the river bank is undoubtedly a 
distinct insect. The Hop-louse has been studied for years, and is not known to go 
from the hop plant to plants of other than the genus Prunus. Your informants are 
also probably in error about the wintering of the Hop-louse on the old vines. * * * 
{March 16, 1891. ] 
The Rose Diaspis. 
- I mail you today box of cuttings from a rose bush badly affected by scale insects, 
which may possibly be the Icerya described in INSEcT LIFE for November, 1890, page 
93. I first noticed it on a fine climbing rose which covered the side of my house at 
Fern Bank, Ohio. This was in the spring of 1889. It spread rapidly, and by last 
season covered the bush completely, although the shoots reached to the eaves of the 
house, and last summer the bush died down completely and all the shoots were cut 
off and burned. The root, however, still lived and threw up new shoots, but I see 
the scale has begun to appear on them also. What treatment can‘ you suggest for 
the case?—[Edwin A. Hill, Ohio, January 5, 1891. 
REPLY.—The insect is not the Icerya rose, as you suggest, but the common Rose 
Seale of this country and Europe—Diaspis rosw. You will find this insect figured 
and described in the Annual Report of this Department for 1880 (pp. 312-315 Plate 
5, Fig. 1). Your best remedy will be to spray your bushes thoroughly with a dilute 
kerosene-soap emulsion, made according to the formula given in Circular No. 1 of 
this Division.—[January 3, 1891.] 
