158 BOARD OF AGRICULTURE. [Pub. Doc. 



eye. They crawl about for a short time, but are not able 

 to reach any great distance, though they may at this time, 

 be transported by other insects or on the feet of birds to 

 other trees in the same orchard or even to other orchards. 

 After these young have crawled about for a time they settle 

 in some suital)le place on a branch or twig or even on the 

 fruit, work their long, slender sucking beaks into the plant, 

 and, in the case of the females, remain during the rest of 

 their existence. Even before they become established, fine 

 threads of wax-like substance begin to issue through minute 

 pores on the surface of the body, and after they become 

 fixed these filaments grow more numerous and longer, till 

 the insect is entirely covered, and as they gradually fuse 

 together, form the scale. As the insects grow, the males 

 moult their skins once while the females moult twice, these 

 moulted skins forming a part of the enlarged scale. 



From the observations made on this insect in Washing- 

 ton, we learn that the female produces her young alive on 

 an average of more than 10 a daj^ continuing for about six 

 weeks, and resulting in a progeny of from 480 to 500 young 

 from a single female. One female was seen to give rise to 

 587 young, by actual count. Professor Howard estimates 

 that there are four full generations in Washington, and that 

 the progeny of a single wintered-over female would amount 

 to 3,216,080,400. From observations made in Massachu- 

 setts, the earliest recorded appearance of the young was 

 June 14 and the latest November 4. This latter date is 

 probably unusual ; but, even if we accept a date in the fall 

 so late as this, we can have but three full generations in a 

 year. The fact, however, that each female gives rise to so 

 large a number of young, even three generations, makes 

 this a most formidable pest. 



It was at first supposed that the San Jose scale would be 

 confined to plants belonging to the Rosacete, which include 

 among others our common orchard and garden fruits, as 

 peaches, pears, apples, plums, cherries, quinces, apricots, 

 raspberries, roses, etc. ; but it was found that it would 

 thrive on plants belonging to other families, including shade 

 and forest trees, as walnuts, willows, elms, maples, locusts, 

 persimmons, gooseberries and currants. 



