INJURIOUS INSECTS OF I909 AND IQIO. 97 
had become so dried as to be of little use. Insects of many different 
kinds were found, but no plant-lice among them. 
A similar canvas shield was raised on a frame of iron piping, 
on May toth, on the southeast corner of the rye-field above men- 
tioned. The shield was faced to the southeast, and held in place 
with ropes attached to the iron frame. This was examined from 
time to time up to July 13th. Insects of many different kinds were 
found upon it; among them, on June 25th, many winged specimens 
of aphid, Callipterus punctata, which breeds on oak. As there were 
no oaks within 300 yards of the shield, these plant-lice must have 
been carried a considerable distance directly by the wind. No 
Macrosiphum, however, were found on this shield at any time. 
On July 15th a new shield was placed on the tower, in the posi- 
tion occupied by the old ones above described, and was examined 
from time to time up to September 8th; but no aphids were found 
at any time upon it, so that the work with these shields, as far as 
plant-lice in general and Macrosiphum in particular are concerned, 
is mostly negative. 
