HABITS AND LIFE HISTORY. 45 
far to the southwest as San Antonio. Tex., the thermometer dropped to 
31° on December 3. A similar, or even lower, temperature was noted 
at New Orleans, yet. on December 10, Mr. Howard found newly hatched 
young, less than 24 hours old. upon a plum tree at Audubon Park. 
Xew Orleans. 
In autumn, or when further development is stopped by cold weather, 
hibernation is begun 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 percentage 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 unquestionably immature, and are fertil- 
ized in this latitude early in April by overwintered males which, as we 
have noted, appear nearly a month before the first young of the spring 
brood. 
The actual rate of the production of young at different periods of 
the lite 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 400, 
there must be born from 9 to 10 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 
hist the young are born with less frequency, and there is a correspond- 
ing reduction in reproductive activity toward the end of the life of the 
individual. The young are born indifferently by day or by night, per- 
haps 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 
observations at nightfall show always as many, and frequently more, 
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 rendered 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 larva' will have 
formed a scale which Mill 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 avail- 
able point. They will not. so tar as observed, travel very far from the 
base of the tree, and in the potted trees none were observed to go more 
than 2 inches from the base of the trunk. 
