SEASONAL HISTORY. 
25 
VARIATION EN THE TIME Of EMERGENCE. 
Tlie variation found in the time of emergence of beetles in different 
vineyards and even in different sections of the same vineyard is due 
to various factors, such as temperature, moisture, porosity and tex- 
ture of the soil, etc. 
Since larvae are found more abundantly in the looser porous soils 
than in the heavy, compact clay soils, and since the former soils are 
warmer, it is but natural that the insect should emerge earlier under 
these conditions. This fact is confirmed by observations presented 
in figure 14, which shows the relative emergence of beetles from three 
grades of soil. For these experiments a number of larvae were col- 
lected in the early spring from different localities in the vicinity of 
North East, Pa. They were confined in large earthen pots (fig. 22) 
with the same kinds of soil in which they had been collected. Since 
these larvae were supplied with a sufficient amount of food and the 
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spttpst j :r «=~pnf« 
::{::::!:::: , :.::)::::::. ::!::::. ::::.:: 
. .. .. .!....!:.: !: ' ! " -t : :ptt:t.:.;j: „.p„tt 
'A. 
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Fig. 14.— Curves showing variations in time of emergence of beetles of the grape root worm from 
different kinds of soil. From rearing experiments during 1909 at North East, Pa. (Original. ) 
pots were placed in the ground in the open, it is believed that their 
normal conditions had been changed but slightly. The emergence 
of beetles from the sandy and gravelly soil was seven days earlier 
than the emergence from the clay soil. 
In the vicinity of North East, Pa., the authors have observed that 
the emergence of the beetle in vineyards situated on the hills is one 
week later than the emergence in vineyards in the valley. This delay 
is not merely confined to the time of emergence of the beetles, but 
has been observed in practically all the different stages of the insect, 
as can be verified from the various tables of field observations. 
FEEDING BEFORE AND AFTER EGG DEPOSITION. 
At the time of emergence from the ground the beetle seems to 
possess a keen appetite. It readily finds its way to the grape foliage, 
and generally feeds upon the first leaf thai it encounters. The leaves 
of the lower shoots are frequently found badly mutilated as a result 
