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P. fusca does not persist in the fields in any numbers as late in 
the season as some of the other species, especially P. rugosa , and some 
of the decline in the proportion of the total comprised by this species 
late in the season was caused by the slow decrease in numbers in the field. 
That the temperature, however, is of importance in determining the extent 
to which this species emerges is shown in figures 2, 3* and. 4, in which 
the percentage of the total beetles represented by each species is shown 
for different localities and on various dates, together with thq air tem- 
peratures prevailing at the beginning of the flight. To avoid err.or in- 
interpreting these charts one should bear in mind that no indication is. 
given on them of the actual numbers of beetles taken, and that P. fusca 
predominated earlier in the season and P, rugosa and P. hirticula later. 
The chart for the Gays Mills grove (fig. 4) shows best the direct 
effect of temperature on emergence. Both P. fusca and P. rugosa are com- 
mon in this area. It may be noted from this chart that on April 26, with 
an air temperature of 73 & F.,.over 90 percent of the beetles we re P. fusca . 
This was probably because none of the other species had begun to emerge 
by that date. By May 2, when the temperature was still high and P. rugosa 
had begun to emerge, most of the beetles were P. rugosa ; however, on 
May 10, when the temperature was 54°, about 60 percent of the beetles were 
P. fusca and by May 12, when the temperature was 54 , this species had in- 
creased to almost 90 percent. When the temperature rose to 6l° on May l6, 
the positions of the two species became again reversed, after which tem- 
peratures remained high and P. fusca beetles were always in the minority. 
This chart also shows that P. ilicis emerges late in the season and does 
not become abundant until considerably after its initial emergence. 
Figure 2 shows the temperature and seasonal relationships at the 
Dane grove, where P. fusca , P. rugosa , and P. hirticula are common. Early 
in the season, although temperatures were high, P. fusca predominated, and 
the low temperature of May 23 increased its proportions. After this date, 
temperatures remained high and this species remained in the minority. It 
may be noticed that the curve for P. rugosa and P. hirticu la in this area 
are almost identical. 
Figure 2 represents similar data from the Leeds grove. In this 
area P. fusca and F. rugosa predominate. The first three collections were 
made when temperatures were 56° F. , or lower. In all three collections,. 
P. fusca beotlcs were most abundant and in the first two no other species 
was taken. On June 13, with a temperature of 62°, P. rugosa predominated. 
