ENTOMOLOGY 111 



far as possible when the greatest percentage of the scales are in a 

 young or partly mature condition. 



The Long Scale. The long scale is supposed to have originated 

 in China, but in common with most of the other species discussed 

 has now a world-wide distribution, being represented in practically 

 every important citrus region. It made its appearance in Florida 

 about 1838, and soon became a very serious pest in that State and 

 elsewhere in the Gulf region. At its first appearance it was vastly 

 more destructive than later on, parasitic and natural enemies having 

 in later years kept it decidedly in check. At present it is every- 

 where distributed throughout Florida and Louisiana in the orange 

 and lemon groves, and also on wild orange. Strangely enough, it 

 was a long while getting into California. About 1889 or 1890, how- 

 ever, in company with the purple scale and rust mite, it was carried 

 into California on a lot of stock from Florida, but it has not de- 

 veloped as a very serious pest in the Pacific coast r6gion. 



This insect is characterized 'by its very elongate form ; in other re- 

 spects it closely resembles the long scale, and also the common oyster- 

 shell scale of the apple and other deciduous fruits. In color it is a 

 rather rich reddish, often obscured by extraneous matter taken from 

 the surface of the leaves or bark. It apparently requires a great deal 

 of moisture to thrive well, and hence is apt to be abundant on oranges 

 or other plants grown in conservatories, and. this also accounts, doubt- 

 less, for its greater multiplication and injury in Florida than on the 

 Pacific coast. Breeding continues practically throughout the year. 

 According to Hubbard, there are three periods in Florida when the 

 young are especially abundant, marking in a rough way the appear- 

 ance of the main broods, namely, in March and April, in June and 

 July, and in September and October; the fourth, irregular brood, oc- 

 curring in January or February. 



The treatment for this scale is the use of the oily washes and fu- 

 migating with hydrocyanic-acid gas. It is much more easily con- 

 trolled than the purple scale. 



The Purple Scale. The original home of the purple scale is un- 

 known, but it now occurs practically wherever the orange or lemon 

 is grown. It was probably introduced into this country at an early 

 date. It is frequently associated with the long scale, and is one of 

 the most troublesome scale insects affecting the orange and lemon, 

 because it is very difficult to get an application on the trees strong 

 enough to kill all of its eggs with one treatment. For many years 

 the purple scale was limited in this country to Florida and the Gulf 

 region, but some years since it was carried on Florida stock into 

 southern California, where, fortunately, it has not yet become widely 

 distributed. In general color it is a brownish purple, and in shape 

 duplicates the oyster-shell scale of the apple. The life history and 

 habits, are the same as those of the long scale. The purple scale is 

 not limited to citrus fruits, but occurs also on many other plants. 



Neither the gas treatment nor any of the washes is a certain 

 remedy for this scale, except in the immature stages. Occasionally a 

 very strong treatment will kill the eggs, but it is usually necessary 



