No. 4.] ORCHARD SCALES. 359 



Townsend, Winchester and Worcester. It is probable that 

 in addition to these fort} r -four places it is present in as many 

 more, existing unrecognized and perhaps unnoticed.* 



How the Scale spreads. 



The most important way in which the scale spreads is, as 

 has already been shown, by its conveyance upon nursery 

 stock. Its spread from tree to tree, however, occurs by 

 means of the crawling young. These are very small, and 

 may easily be blown off the tree they are on by sudden gusts 

 of wind, and, if carried to another tree, or even very near it, 

 may be able to establish themselves. Others crawl onto the 

 feet of birds or even other insects as these rest on infested 

 trees, and when they fly to other trees may crawl off there. 

 If the branches of adjacent trees touch, the young may 

 crawl directly from one to another. 



Enemies. 



The San Jose scale is not without its enemies, which prey 

 upon it. Chief among these are the lady-birds, or lady- 

 bugs, as they are commonly called, perhaps the most 

 common one which feeds upon the scale being the "Twice- 

 stabbed lady-bug," which is a small, shining black beetle, 

 about an eighth of an inch long and nearly as wide, with its 

 upper surface very strongly convex, and with two dark-red 

 or orange spots on the back. This insect is of much aid in 

 the destruction of the scale, but unfortunately its rate of 

 increase is so much less than that of the scale that it is un- 

 able to do more than somewhat reduce the numbers of the 

 pest. 



There are several parasites of the scale, as well ; but here, 

 too, their rate of increase is less rapid than that of the scale, 

 which of course renders their work of less value than would 

 otherwise be the case. 



A fungus occurs in the southern States which also attacks 

 the scale, and this has been cultivated somewhat, in the hope 

 that it might be made use of in controlling the insect. 



* April. 1902, over 60 places are now known to be infested. 



