GRAPEVINE FLEA-BEETLES. 
19 
DURATION OF CALLOW PERIOD. 
The duration of the callow period of the adult stage, or the period 
after transformation of the pupa to adult and before its emergence 
from the ground, was recorded for 48 individuals. It varied from 
1 to 4 days, with an average of 2.19 days, as 
shown in Table XXVI. The period covered 
by these records extended from July 28 to 
Table XXIY . — Prepupal 
stage of A . woodsi, North 
East, Pa., 1917. 
August 11. 
SUMMARY. 
Number 
of individ- 
uals. 
Duration 
of period. 
Days. 
29 
4 
19 
5 
7 
6 
2 
7 
157 
2 4.68 
Total. 
Weighted average. 
The seasonal history of the lesser grape- 
vine flea-beetle is similar in general to that 
of the larger species, but it is later through- 
out. There is a single generation annually, 
winter being passed in the adult stage. 
Beetles emerge from hibernation in the latter 
part of May or early June, some time after 
the grape shoots have expanded, or about 
three weeks later than the typical species. Oviposition begins early 
in June and continues until the latter part of July, when the last 
adults disappear. 
The average duration of the incubation period was 12.82 days in 
1916 and 13.72 days in 1917, slightly less than that of the larger 
species, but this difference may be accounted for by the fact that 
these incubation records were taken later in the season, when the 
temperature was higher. 
Table XXV. — Duration of pu- 
pal stage of A. woodsi, North 
East, Pa., 1917. 
Table XXVI. — Callow period of 
adult stage of A . woodsi, North 
East, Pd., 1917. 
Number 
Duration 
of pupae. 
of stage. 
Days. 
10 
6 
16 
7 
17 
8 
2 
9 
145 
2 7.24 
Number 
of individ- 
uals. 
Duration 
of period. 
Days. 
12 
1 
19 
2 
13 
3 
4 
4 
148 
2 2.19 
1 Total. 
Weighted average. 
1 Total. 2 Weighted average. 
Larva3 are found on the vines in midsummer, the records of collec- 
tion extending from June 18 to August S. The average duration of 
the larval feeding period was 18.71 days in 1916 and 18.59 days in 
19 1 7, or about one-fourth shorter than that of the ' ' large form. ' ' The 
duration of the three larval stages was as follows: First stage, 6.16 
days in 1916 and 6.35 days in 1917; second stage, 6.46 days in 1916 
and 6 days in 1917; third stage, 6.51 days in 1916 and 6.62 days in 
1917. 
