138 



ORDER IIEMIPTERA 



season. It has been estimated that a single female may be 

 the parent of about three and a half billions in a single 

 season. Since there is no egg, but young are brought forth 

 alive, they must ha\^e constant nutrition, and unless the scale 

 is attached to living tissue the insects must perish, except 



Fig. 91. — San Jose scale: c, adult female containing young — greatly 

 enlarged; d, anal fringe of same — still more enlarged. (After Howard.) 



that mature females may assume a dormant condition dur- 

 ing cold weather. The only means of transportation to 

 distant points, therefore, appears to be upon living plant 

 tissue, and this makes it possible to prevent its distribution 

 by adopting restrictive measures through inspection and 

 quarantine. 



