10 
BULLETIN" 254, U. S. DEPARTMENT OE AGRICULTURE. 
From the notes made by Mr. Wildermuth at Tempe, Ariz., in 1913, 
for the first spring generation the average length of the nymphal 
stage during March and April is shown to be 40 days, a few days less 
than that obtained the following year by the writer. (Table V.) 
Table V. — Length of nymphal stage of the sharp-headed grain leaf hopper, Tempe, 
Ariz., 1913. 
Nymphs emerged 
from egg. 
Adults emerged 
from last 
nymphal molt. 
1 
Length of 
nymphal 
stage. 
Mar. 18 
Mar. 24 
Mar. 27 
Mar. 24 
Average 
Apr. 20 
May 5 
do 
Mav 10 
Bays. 
33 
42 
39 
47 
40. 25 
HIBERNATION AND WINTERING. 
Prof. Osborn 1 states that " hibernation seems to occur in all stages 
from the egg to the adult, although the great majority must pass the 
winter in the egg stage." At Tempe, Ariz., the writer searched 
diligently during January, 1914, for all stages of the species but 
found only adults. No eggs were deposited in cages either in or out 
of doors until February 4. Dissections of adult females during 
January showed them to be full of immature eggs. An experiment 
was carried on in which young nymphs were submitted to a tempera- 
ture of 35° F. for 18 hours, at the end of which all nymphs were 
dead, showing that it is improbable that young nymphs could ever 
withstand the winter. Mr. F. H. Gates, another assistant of the Bu- 
reau of Entomology at Tempe, reports having taken adults on a 
number of days during November and December, 1914, and January, 
1915. On December 15 he took several nymphs which were prob- 
ably in the fourth or fifth instar. From his observations it would 
seem that the nymphs which had attained the fourth or fifth instar 
by late fall might survive the winter, although up to December 15 
there had been no really cold weather at Tempe, the minimum tem- 
perature recorded to that date having been 28° F. At Charleston, 
Mo., during November and December no eggs or nymphs could be 
found, while the adults were present and active on warm days. It 
seems safe, therefore, to assume that the species winters over princi- 
pally in the adult stage throughout the Southern States and in all 
probability the same holds true throughout the country. 
GENERAL ACTIVITIES OF THE ADULTS. 
The adults are exceedingly quick of movement, and might well be 
described as restless. They are easily disturbed or frightened and 
Op. cit., p. 58. 
