10 BULLETIN 900, U. S. DEPARTMENT OF AGRICULTURE. 
this period extended from July 13, the earliest recorded date of 
pupation, to August 12, the latest recorded date of eclosion of an 
adult — exactly the same length of time as recorded for 1916. 
ECLOSION OF MOTHS IX 1917. 
Eclosion of moths in 1917 extended from July 24 to August 12, 
with the height of the period about August 2. The dates of eclosion 
of moths reared are given in Table II. 
SUMMARY. 
There is one generation annually in the Erie-Chautauqua grape 
bert, winter being passed in the egg stage. Insectary records in 
1917 show that eggs hatched from June 2 to June 15 inclusive. 
Field observations, while indicating that a few individuals may have 
hatched a week or more earlier, showed that the great majority of 
the eggs must have hatched during the first two weeks of June, con- 
firming the insectary records. The hatching of larvae in numbers 
occurred about three weeks before the grape blossoming period in 
1917. The duration of the feeding period of most larvae was from 
6 to 7 weeks, averaging 46.12 days. Preparatory for pupation the 
larva secures itself by a loose web spun on a fold of a leaf or grape 
cluster. Two days are spent as prepupa and about 10 as pupa. 
The moth emerges in midsummer and deposits eggs which hatch the 
ensuing year. 
It should be noted that the season of 1917 was a very late one, the 
grape blossoming period being about three weeks later than usual. 
It might be expected, therefore, that in a normal season the larvae 
would hatch in considerable numbers in May and the earliest moths 
might even appear in June. 
HABITS. 
LARVAL HABITS. 
As they hatch the larvae eat out the micropyle and emerge from 
the egg, leaving the shell apparently as it was before. The newly 
hatched larvae promptly migrate, scattering over the cane or vine on 
which the eggs happened to be placed. They are strictly solitary 
in habit and resent crowding. When two larvae accidentally come 
in contact one is apt to strike viciously at the other, swinging its 
entire body in front of the prolegs like a whip and often knocking the 
intruder off the leaf. If both larvae have a secure foothold a duel is 
apt to follow. In cages the writer has observed instances of canni- 
balism but this does not seem to be common. Because of this 
solitary habit seldom more than two or three are found on a single 
grape leaf. If crowded in cages the mortality is very high. 
The grapevine looper progresses by the alternate measuring and 
looping movement characteristic of members of this group. It ex- 
