INJURIOUS INSECTS OF I909 AND IQIO. 33 
white birch, linden, currant, box elder, mountain ash, willow, dog- 
wood and plum. Even in the case of the two last we have no 
certain proof that the specimens of E. mali reared from them did 
not first hatch from eggs in blisters on apple trees, and then get 
blown from the apple to the plum and willow trees, which were 
about fifty yards distant, though the chances for this, considering 
the observations made by sweeping on alfalfa, do not seem great. 
Notes and Observations on Life-History. 
On June 4th trees of the orchard on the flat were examined 
for this species; no adults were found on the apple trees, though 
nymphs were present in all stages. The alfalfa field just across the 
road was examined, to the north of this orchard, and swept with a 
fine collecting-net, and adults of EF. mali were found. No nymphs 
in any stage were found upon the alfalfa at this time, which again 
shows that this species does not pass the winter in the egg stage on 
or in alfalfa. The adults found on the alfalfa at this time had 
evidently come to maturity on the apple trees in the neighboring 
orchard, and then either flown or been blown by the wind from 
these trees on to the alfalfa. Counts were made of the number of 
specimens of adults that were taken by sweeping across the alfalfa 
field at various distances from the orchard. The field was 164 
paces long, extending directly away from the orchard, and the 
width being about the same (52 paces) from end to end. For 
each count the width of the field was swept, taking one good sweep 
of the net at every step. The following table gives the number of 
sweepings, their distance from the orchard, and the number of 
Empoasca captured. 
Paces from Orchard Number of specimens taken Sweepings. 
9 5 Once across. 
130 1 Once across. 
13 5 Once across. 
21 3 Once across. 
40 6 Once across. 
60 8 Once across. 
80 3 Once across. 
100 4 Twice across. 
120 3 Once across. 
140 2 Once across. 
164 
eo 
Twice across. 
