44 THE SAN JOSE SCALE. 
Perhaps the most notable feature of the foregoing records is the 
result obtained from the overwintered females. It will be seen that 
the males greatly predominate in this generation, and that the numbers 
of both sexes are insignificant compared with the progeny of the later 
generations. The males still predominate in the second generation, 
but in the third and fourth generations the females considerably out- 
number the males, in one instance the females from a single mother 
reaching the astonishing number of 464, which, with 122 males from the 
same parent, makes the progeny of this female 586 insects. Taking 
200 females as an average of the different generations for the year, the 
product of a single individual from spring to fall amounts to 1.608,040,200 
females. In one instance we have over 415 males from a single female, 
and while the number of males would average somewhat less than the 
females, taking the summer through, yet, having underestimated the 
females, the males may be estimated at the same number, giving a 
total of 3,216,080,400 descendants from a single insect in a single sea- 
son. It is not to be expected, of course, that all the individuals from a 
scale survive and perform their function in life, but under favorable 
conditions, or in the case of a tree newly infested or not heavily 
incrustecl, the vast majority undoubtedly go through their existence 
without accident. Neither the rapidity with which trees become 
infested nor the fatal effect which so early follows the appearance of 
this scale insect is therefore to be wondered at. 
Owing to the long period during which the female is continuously 
producing young, the different generations or broods in the course of the 
summer are not distinctly marked and merge insensibly into each other — 
so much so that at almost any time there will be found young larvae 
running about over the trees and scales in all stages of development. 
Still, at certain times the young will be noticeably more abundant, 
indicating periods when the majority of each generation are producing 
young. In this latitude the first young appear, as noted, by the middle 
of May, at Amherst, Mass.. they were first noticed June 12, and in 
Arizona they are recorded as appearing in March. The larvre are con- 
tinuously present on the trees until further hatching is prevented by 
severe frosts. In 1894, as we have already shown on page 289 of Vol- 
ume Til of Insect Life, the first frosts at Washington occurred in the 
latter part of October and the hatching of the young ceased before the 
1st of November. October 24, 1894, however, Mr. Howard saw recently 
settled larva? , not more than 5 days old, at Lewisburg, Pa. In 1895 the 
October frosts were insignificant, and in this neighborhood no severe 
frost occurred until about the 1st of December. The result was that 
young larva? were found at Washington until late in November, while 
on twigs received from Chestertown, Md., November 13 and November 
27, the young were more or less abundant. The cold spell of the last 
week in November and the first week in December put a stop to 
development here. This same cold spell was of very wide extent. As 
