LIFE HISTORY. 
Record showing fecundity of San Jose scale. 
49 
Number of tree. 
Males. 
Females. 
Total. 
Progeny of over wintered 
females. 
106 
120 
198 
40 
158 
58 
13 
72 
34 
77 
43 
138 
60 
18 
22 
98 
60 
33 
25 
13 
| Progeny of second gener- 
585 
502 
417 
312 
556 
330 
350 
avion . 
235 
276 
226 
325 
92 
192 
120 
415 
151 
206 
124 
Number of tree. 
1 
2 
3 
4 
5 
6 
1 
2 
3 
4 
5 
6 
Milk's. 
Females. 
Progeny of third, 
tion. 
307 
464 
284 
400 
280 
274 
of fourth 
tion. 
Total. 
110 
122 
190 
187 
174 
107 
Progeny 
242 
319 
112 
230 
92 
170 
210 
344 
242 
343 
156 
293 
genera- 
ill 
586 
474 
587 
454 
354 
genera- 
561 
342 
262 
554 
585 
449 
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. Tak- 
ing 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 some- 
what less than the females, taking the summer thru, 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 season. 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 incrusted, the vast majority undoubtedly go thru their 
existence without accident. Neither the rapidity with which trees 
become infested nor the fatal effect which so early follows the appear- 
ance of this scale insect is therefore to be wondered at. 
Owing to the long period during which the female is continuously 
producing } r oung 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 
