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 IMPORTANCE 



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 form. 



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, P s y 1 1 a 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. 



