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THE WESTERN PTJIiVINARIA OR COTTOlTy SCALE. 



This insect is considered to be merely a variety of the Eastern cot- 

 tony maple-scale, but it is very different in its food plants. While the 

 Eastern insect attacks only the maple, the Western variet}" never is 

 found on maples but has quite a long list of host plants, namely, cur- 

 rant, gooseberry, pear, mountain ash, lilac, alder, poplar, hawthorn, 

 and willow. So far as known the life history is as follows: 



During May and June the female lays the eggs in large numbers in 

 a mass of white waxy fibers secreted from the posterior end of her 

 body. As the eggs develop they expand the waxy mass and raise the 

 insect's body to a considerable angle to the twig on which it is attached. 

 If the waxy mass is crushed at this time blood-colored streaks appear, 

 arising from the eggs and the bodies of the young larvte which hatch 

 from the eggs. These larvae resemble lice and run about over the 

 plant actively. About the time the last eggs are laid the female dies, 

 but the tough leathery scale and the fluffy mass of fibers cling to the 

 twig for a long time. 



The young insects settle themselves on young twigs, insert their 

 beaks, and begin to suck sap. They increase in size rapidly, after 

 having covered themselves with tough waxy substance for protection, 

 and reach their full size in August. About this time the male insects, 

 which are narrower than the females, change into pupte and soon after 

 emerge as delicate two-winged creatures. After a few days' life, in 

 which they pair with the female, the}'^ perish. 



The females never become winged and seldom leave the branch on 

 which they are born. After the flow of sap ceases they become dor- 

 mant until the following spring. 



As the female never acquires wings it seems at first sight difficult to 

 account for the spread of the insect. Perhaps the most effective means 

 of spreading the insect has been by infested nursery stock, as the 

 insect is inconspicuous in winter. No doubt birds now and then carry 

 the active young larva?, which have crawled upon them, for consider- 

 able distances. Only thus can the fact be explained when the insect 

 is found on a wild tree some distance from the nearest garden. 



Remedies. — Spray during May and June with kerosene emulsion or 

 whale-oil soap solutions, the aim being to destro}' the 3'oung larvae. 

 Two sprayings are necessary, the first about the time the cotton}' 

 mass is most conspicuous, the second a week or ten days later. On 

 currant and gooseberry bushes the first spraying would be at the time 

 the fruits are fully grown but before they have begun to ripen; the 

 second spraying may be deferred until the crop is picked. 



Winter spraying with the sulphur-salt-lime wash or with a strong 

 solution of whale-oil soap, using 1^ or 2 pounds of the soap to a gallon 

 of water, would doubtless prove completely effective, but so far as 

 we know the actual experiment has not been carried out. 



