324 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
their last molt, and by the end of autumn they had stripped most 
of the trees, showing, however, a decided preference for the black, 
red, and rock-chestnut oaks, over the white oaks and hickories, 
which they affect but little until after the first-mentioned trees 
are stripped. The underbrush was 
also very effectually cleaned of its 
foliage, and the insects hung from 
and clung to the bare twigs and 
branches in great clusters. They 
settle to roost on the witch-hazel, 
but do not defoliate it until the 
other trees mentioned are pretty 
bare. Sumac and thorn are also 
little affected, while peach and apple 
in an adjoining orchard were un- 
touched. Whenever they have en- 
tirely stripped the trees and shrubs 
they move in bodies to fresh pastures, 
crowding upon one another and cov- 
ering the ground, the fence rails, and 
everything about them so that it 
is impossible for a person to enter 
the woods without being covered by 
them. The timber affected can be 
recognized by its seared and leafless 
appearance from a great distance, 
and upon entering the woods the ear 
is greeted by a peculiar seething noise, 
resulting from the motion of the 
innumerable jaws at work on the 
leaves." 
A more recent outbreak is reported 
from Iowa in the summer of 1913 
(Journ. Econ. Ent., vol. 7, p. 299, 
1914) by Miss Butler, in part as follows : "The woods are princi- 
pally oak, with smaller numbers of elm, ash, aspen, Hnden, hickory 
and black walnut trees and a heavy undergrowth of hazel. On 
the 30th of May it was observed that the hazel bushes were 
quite covered with recently hatched walking-sticks, varying from 
Fig. 43. — Northern Walking-stick, 
Diapheromera femorata. Natural size. 
(After Lugger.) 
