38 INSECTS INJURIOUS TO FORESTS. 
yet begun to molt. A large number were placed in a covered tin box 
34 by 5 by 14 inches, with disintegrated wood and moist earth in the 
bottom. This was to be a check box, and the conditions here were 
more natural than in the small corked vials, in which over 100 other 
nymphs had been kept in the dark, one nymph to each vial. The 
development of each nymph was watched and the time necessary for 
the various changes from nymph to adult was noted. On June 8 
fully developed nymphs of virginicus, with opaque wing pads, were 
observed to molt in asimilar manner. Nymphs in all stages described 
for flavipes were observed molting until June 11. 
As E. H. Strickland has already figured and described these 
changes in the nymphs of the first form (flavipes), his accurate 
description is here quoted in detail, with a few comments. Until 
this description appeared, the quiescent stage in the development 
from nymph to adult for this species was undescribed. His obser- 
vations were made from nymphs collected in the neighborhood of 
Boston, Mass., May 7, 1910. 
The mature nymph becomes very sluggish and finally all movement ceases; it 
then falls over on its side and the head is bent down till it lies on the ventral side 
of the body, along which also the antenne and legs are extended in a backward 
direction, * * * while the wing pads are bent downward till they lie laterally 
along the sides of the body. * * * It will be at once noticed that while in tnis 
position the nymph is to all appearances a quiescent ‘pupa libera.”” There does 
not appear to be an ecdysis immediately prior to this quiescent period, however, 
so I would hesitate to describe it as a true pupal state though it undoubtedly has 
the same physiological function. 
This quiescent stage lasted in the few specimens observed for a period varying 
from four to about nine hours. The duration in time seems to be controlled to a 
large extent by the amount of moisture in the earth surrounding the pupa for when 
specimens were placed in perfectly dry earth they were unable to pass beyond this 
stage of development,’ while the greater the amount of moisture, the shorter the 
period. During this stage the last nymphal skin splits across the head and along 
the dorsum, and is slowly worked downward and backward till a large portion of it 
hangs freely from the apex of the abdomen on the ventral side. The legs are the 
last part ¢ of the body to be freed from this skin, which then becomes detached as 
a much crumpled mass. As soon as the wings are liberated they begin to move 
away from the body at their base. This is apparently due to the trachex in the 
basal portion of the wing becoming inflated. The inflation, however, does not 
extend beyond the suture along which the wing is subsequently broken off, and 
the distal portion remains tightly folded. * * * 
The ecdysis described above is the last in the development of the imago, for the 
insect now disclosed is the sexually complete@ adult; it does not, however, become 

a Varying from about 3} to 12 hours at Falls Church, Va.—T. E. S. 
b A considerable amount of moisture’ apparently is essential to normal develop- 
ment. Specimens placed in small, individual, corked vials molted normally, while 
others placed in vials the mouths of which were lightly plugged with cotton developed 
abnormally, with distortions, or not at all.—T. E. 8. 
c Sometimes the antennz are the last part to be freed of the cast skin in case of 
nymphs of both the first and second forms.—T. E. S. 
@ At this stage the sexual organs are not yet fully functionally matured,—T. E. 8. 
