370 REPORT OF STATE BOARD 0¥ HORTICULTURE. 



to the southwest as San Antonio, Texas, the thermometer dropped to 31° on 

 December 3. A similar, or even lower, temperature was noted at New 

 Orleans, yet, on December 16, Mr. Howard found newly hatched young, less 

 than twenty-four hours old, upon a plum tree at Audubon Park, New 

 Orleans. 



In autumn, or when further development is stopped by cold weather, 

 hibernation is beg-un by scales in all stages of development, from the white, 

 minute, down-covered recently hatched young to the mature and full-grown 

 females and males. Unquestionably many young perish during the winter, 

 and normally in spring quite a pei'centage of the smaller or half-grown scales 

 will be found to have perished. It is very probable that many females have 

 union with the males in the fall, but the majority of them are unquestion- 

 ably immature, and are fertilized in this latitude early in April by over- 

 wintered males which, as we have noted, appear nearly a mouth before the 

 first of the young spring brood. 



The actual rate of the production of young at different periods of the life 

 of the adult female has not been determined with accuracy. As the average 

 reproducing period of the adult female is six weeks, and as the average 

 number of young from each female is about four hundred, there must be 

 born from nine to ten young every twenty-four hours. The great labor of 

 watching an individual female and removing every twenty-four hours the 

 young she has given birth to during that period has not been entered upon. 

 Sufficient observations have been made, however, to indicate that the main 

 period of reproductive activity is the second or third week after the female 

 has reached maturity. At first the young are born with less frequency, and 

 there is a corresponding reduction in reproductive activity toward the end 

 of the life of the individual. The young are born indifferently by day or by 

 night, perhaps more during the day than during the night. In the morning, 

 however, examination of the trees under observation always shows many 

 migrating young which must have been born during the night, while obser- 

 vations at nightfall show always as many, and freqnentlymore, which have 

 been born during the day. 



The gradual production of the young by the female has an important 

 bearing on'the question of remedies, and the old washes, which aimed at the 

 destruction of the young- as soon as they emerge from the females, are ren- 

 dered almost valueless because, to make them effective, it is necessary to 

 repeat them many times during a period of six weeks. Within two or three 

 days after hatching the young larvae will have formed a scale which will be 

 impervious to these weaker washes. 



The larva does not ordinarily travel far from the parent insect, and 

 usually rests within a few inches of the old scale or at the first available 

 point. They will not, so far as observed, travel very far from the base of the 

 tree, and in the potted trees none were observed to go more than two inches 

 from the base of the trunk. 



