428 



BOARD OF AGRICULTUKE. [Pub. Doc. 



tion now begins, the young being born alive at the rate of 

 three or four or more nearly every day for about a month, 

 after which the parent dies. By this time the first-born 

 young are now adult and l)eginning to produce young, how- 

 ever, so that young scale insects may be found at almost any 

 time from about the fifteenth of June till winter stops their 

 production, though they are more abundant at certain times 



during this period 

 than at others. 



That an increase 

 in this way must re- 

 sult in the produc- 

 tion of an enormous 

 number of n e w 

 scales is evident. 

 It has been calcu- 

 lated that if all the 

 j)rogeny of a single 

 female which begins 

 breeding in June 

 should survive and 

 reproduce in their 

 turn, the number of 

 female descendants 

 of this female when 

 Av inter s t o }) s re- 

 l)roduction Avould 

 be l,(i()8,040,200; 

 and, Avhile this is 

 never the case, it is 

 not strange that, 

 Avith even a small proportion of this number of insects suck- 

 ing the juices from the plant, severe injury should ensue and 

 often cause its quick death. 



The voung scales are very small, oval, vellow insects, with 

 six legs, which the}'^ use in crawling about in search of a 

 place upon which to settle. It is probable that, Avhile they 

 may move about for four or five days before they locate per- 

 manently, in most cases it is less than two days. 



Fig. 2. — San Jose scale on pear: fi, natural size; h, 

 imioh enlarged. (Howard, Circ. 3, 2d ser., IHv. of Ent., 

 Uept. of Agr.) 



