SCALE INSECTS. 19 



each side of each of these incisions is a club-shaped thickening of 

 the body wall. 



" There are two inconspicuous simple plates between the median 

 lobes, and on each side similar plates extending caudad of the first 

 incision, three small plates serrate on their lateral margin caudad of 

 the second incision, and the club-shaped thickenings of the body 

 wall bounding it, and three wide prolongations of the margin be- 

 tween the third and fourth spines. These prolongations are usually 

 fringed on their distal margins. There are also, in some, irregular 

 prolongations of the margin between the fourth spine and the penul- 

 timate segment. 



" The first and second spines are situated laterad of the first and 

 second lobes, respectively; the third spine laterad of second incision ; 

 and the fourth spine about one-half the distance from the first lobe 

 to the penultimate segment." 



How Disseminated. 



The female scale, as previously stated, is wingless; hence 

 is dependent solely upon more active agencies for the dis- 

 tribution of its species. These agencies might come under 

 two classes: First, transportation from one locality to 

 another, one state to another — in a word, places remote from 

 each other; second, points close at hand, such as different 

 trees in the same orchard or orchards in the same neighbor- 

 hood. Under the first, transportation of nursery stock is 

 the most effectual means. Here the insects may have lived 

 before shipment and can exist in transit. No other single 

 agency has been so potent is distributing this pest. In al- 

 most every instance the cause for first appearance in a state 

 has been traced back to importation of young trees or cut- 

 tings from an infested region. 



Fruit, such as pears, from infested localities carries with 

 it this scale. By throwing the parings of svich near the 

 trees the young can readily creep up the trunks and locate 

 at a suitable place to start a colony. Such fruit is by no 

 means rare upon the markets. 



Since the young insects or larvfe crawl only short dis- 

 tances, the second means of spread, that is, from tree to 

 tree, must be brought about by outside forces. The wind 

 may aid a little by blowing forms across from one tree to 

 another. Birds and insects are the means here used suc- 

 cessfully. The young larvae will crawl upon the feet of 

 birds or the bodies of other insects. Instances of the use 

 of these means of conveyance have been observed. 



