8 
BULLETIIv' 901, U. S. DEPAETMEXT OF AGRICULTURE. 
Table I. — Feeding period oftTiird 
larval stage of A. chahjhea, Xorth 
East. Pa.. 1916. 
1 by 4 inch ^4als. Transformations from the prepupal and pupal 
stages to the adult were passed in vials of the same size partially 
filled with earth. To determine the duration of each of these periods 
in the ground two methods were employed^ as follows: 
The first was to place a vial five-eighths of an inch in diameter 
inside of a vial 1 inch in diameter, filling the space between the two 
with earth. In this narrow space mature larvae were placed and 
most of them were forced to form their pupal cells next to the glass 
surface, where their transformastions could be observed readily. The 
outer vial was covered with black paper, which was removed only 
when observations were being made. For convenience of identifica- 
tion each cell was marked with a wax pencil. This method was 
faulty, because of the difiB.culty of mahitahiing the normal soil mois- 
ture in so thin a layer. 
It was later learned that by pressmg the earth in the middle of the 
vial, leaviQg the earth at the sides comparatively loose, about haK of 
the larvae would form pupal cells along 
the sides of the glass. It was necessary, 
of course, for success with this method, 
as with the former, that the vials be 
wrapped with black paper. This method 
was most used in 1917. 
These methods of observhig trans- 
formation in the ground were developed 
in the latter part of 1916 and the data 
on these transformations secured durhig 
that season are very meager. Hence 
records for the prepupal, pupal, and 
callow adult stages of both species are 
given only for 1917. 
Detailed life-history studies of the typical grapevine flea-beetle 
did not begm m 1916 until the majority of the larvae were at least 
half grown, smce they were undertaken for comparison with the more 
common "small form." Accordingly rearing records cited below 
begin with the third larval stage in 1916. 
DURATIOX OF FEEDING PEPvIOD OF THIRD STAGE IX 1916. 
The din^ation of the feediag period of the thhd larval stage varied 
from 6 to 13 days, with an average of 7.75 days, as shown in Table I. 
The period covered by these records extended from June 12 to July 8. 
Number 
Duration 
of larvs. 
of period. 
Days. 
18 
6 
29 
7 
17 
8 
15 
9 
6 
10 
2 
11 
2 
13 
18^ 
2 7.75 
Total. 
i Weighted average. 
DUEATIOX OF PERIOD IX GROUXD. 
The duration of the period hi the ground of 87 individuals 
reai'ed vaiied from 15 to 24 days, with an average of 20.71 days. 
