THE WALKING STICK. 319 
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. Their depredations first begin to 
attract attention soon after wheat harvest, and are most noticeable in September. 
The injury to the trees done in 1874 and 1876 was manifest in the death of most of 
the black oaks, and according to Mr. Snow's observations, trees die in three years 
after the first attack. 
The unexampled multiplication and destructiveness of this insect at Esperange 
farm is but one of the many illustrations of the fact long since patent to all close 
students of economic entomology, that species normally harmless may suddenly 
become very injurious. 
Owing doubtless to its having so generally been considered harmless, the habits of 
the thick-thighed walking-stick have not hitherto been carefully studied ; and it 
was not known how it passed the winter or where the eggs were laid. These eggs, 
which were first briefly described by me in 1874,* are 2.8 mm long, oval in shape, 
slightly compressed at the sides, and of a polished black color, with a ventral whitish 
stripe. They look not unlike some plump, diminutive leguminose seed. They are 
simply dropped loosely upon the ground from whatever height the females may 
happen to be, and, during the latter part of autumn, where the insects are common, 
one hears a constant pattering, not unlike drops of rain, that results from the abun- 
dant dropping of these eggs, which in places lay so thick among and under the dead 
leaves that they may be scraped up in great quantities. 
From general observations of specimens kept in confinement it would appear that 
each female is capable of laying upwards of a hundred. The eggs remain upon the 
ground all through the winter, and hatch for the most part during the month of May. 
Some of them, however, continue hatching much later, so that all through the sum- 
mer and even into the fall young individuals may be found. The embryo just about 
to hatch lies within the egg with the head pressed against the oval lid, and the body 
curled around so that the end of the abdomen, which is thickened and contracted, 
reaches near the mouth. The long antennae project in front of the head and follow 
the curve of the body, and the long legs are folded up in the central space. At an 
earlier embryonic stage the abdomen is enormously enlarged and the members are 
correspondingly small. The young walking-sticks measure at birth 4.5 mm , and, with 
their feelers and legs outstretched, nearly double that length. They are invariably, 
during early life, of a uniform pale yellowish-green color, and as they have a habit 
in their earlier days of keeping near the ground, this, coupled with a great readiness 
to drop whenever disturbed, serves to protect them from observation. They may for 
these reasons occur in great numbers in the early part of the season without being 
suspected. The insect changes very little in appearance from birth to maturity 
except so far as color is concerned, and molts but twice. Growth is rapid, averaging 
under favorable circumstances about six weeks from birth to maturity. With age 
the green color gives way to various shades of gray and b*own. In this way we find 
great correspondence with its surroundings. While the vegetation is green the 
specters are green also ; when the foliage turns in autumn they change color corre- 
spondingly, and when the foliage is stripped they so closely resemble, in bothappear- 
auce and color, the twigs upon which they rest — the habit of stretching out the 
front legs and feelers greatly enhancing the resemblance — that when they are few in 
numbers it is difficult to recognize them. A few green specimens, more particularly 
of the males, may always be found, even among the mature individuals. 
In contemplating these singular creatures and their wonderful resemblance to the 
oak vegetation upon which they occur, one can not help noticing still further resem- 
blances. They are born with the bursting of the buds in the spring ; they drop their 
* New York Weekly Tribune, November 11, 1874. 
