120 NEW YORK STATE MUSEUM 
added that the imported fluted scale, Icerya purchasi Mask., 
threatened the entire citrus fruit industries of California in the 
80’s and was effectually subdued only by the importation of nat- 
ural enemies. 
We have made an attempt to classify these imported insects 
according to their destructiveness or prospective importance; and 
the following annotated lists give our judgment regarding some 
of these forms. 
INTRODUCED SPECIES OF PRIMARY ECONOMIC IM PORTANC®: 
Affecting fruit trees 
San Jose scale. ASpidiotus perniciosus Comst. This 
species, though recently introduced, is already widely distributed 
over the United States and easily ranks as one of the most in- 
jurious scale insects in the country and is probably as destructive 
as any other imported fori. 
The black scale, Lecanium oleae Bern., is very injurious, 
particularly to oranges and lemons in southern California. 
The codling moth, Carpocapsa pomonella Linn., is one 
of our older pests and yearly causes great losses, as mentioned in 
a preceding paragraph. 
The brown tail moth, Euproctis chrysorrhoea Linn, 
is one of our most recently introduced species, which promises to 
be not only quite injurious to peartrees, but also very annoying 
to man, since the irritating hairs of its caterpillar have caused 
very serious inflammations, in neighborhoods where the insect 
was numerous. 
The gipsy moth, Porthetria dispar Linn., though of com- 
paratively recent introduction and still confined to a somewhat 
limited territory, is a species of prime economic importance and 
may eventually become one of the most destructive in the country. 
It fortunately spreads slowly and may be controlled locally. 
The pear psylla, Psylla pyricola Forst., though first de- 
tected in Connecticut, probably entered the country through the 
port of New York and is exceedingly destructive to peartrees in 
some years. It has obtained a wide distribution in New York 
State and is known to occur as far west as Illinois. 
