Puant Lice InyJuRING FOLIAGE AND FRUIT OF THE APPLE 709 
Succeeding generations 
The generations of Aphis pomi follow one another with great regularity 
and rapidity. This succession may be easily grasped by examining the 
chart (Reproduction Chart I) and figure 116. Each generation after the 
first of June matured in from eight to twelve days, the maximum period 
being for the eighth generation, during the last of July, and the tenth 
generation, in the latter half of August. 
2d generation 
ed : | 3 
= 3d gerreratio 
ae Ah gereration 
(Of gerrerarior aa 
It Gerier aia? 
g f , 
137/79 gerrerarior7 
20° 30 2:5 iby 245) 4 14 24 14 24 4 14 24 3 13 23 3 323) 
April May June July August September October 
| 
a S51 alas | 
al (ee lace 
4 674 gerrerarion 
| 
—-—t- | 71 deere 
emu [baal ee se 
—————4 874 gererarion 
eee a eli 
ae 9/4 gerrerarorr 
rr ye eee 
Saas ee 
Fic. 116. GENERATIONS OF APHIS POMI 
The part of the line between the round dots represents the productive period; the remainder of the line 
represents the period of life after production ceased 
The habits and activities of these later generations present no great 
variations from those already discussed. Altho reproduction continues 
at a very high rate and there are many overlapping generations, yet 
the activities of the many predacious and parasitic enemies of the insects 
usually hold them fairly well in check. However, severe outbreaks have. 
occurred and may be expected to continue to occur at any period during 
the summer.. The detailed report and discussion of the parasitic and 
