53 
plete atrophy of the hind gut, at any rate so far as to render its 
dissection extremely difficult. 
During the late pupal condition and early adult there ap- 
pears a somewhat anomalous metamorphosis of the mid gut, the 
first indication of which appears as a slight enlargement of the 
tract in this region and an internal vesicular cavity. This cavity 
increases in size with the growth of the Cicada to maturity after 
emergence and with increasing age it becomes the cavernous 
structure to which reference has been made above. Coincident 
with this change there was a decrease of the amount of adipose 
tissue which gradually dissappeared by absorption as will be sub- 
sequently shown. With the enlargement of this portion of the 
tract the convoluted character of its epithelium, ‘so characteristic 
a feature during the larval period, gradually disappears almost 
entirely, the inner surface appearing quite plain and smooth as 
seen under the dissecting microscope. A histological examina- 
tion of the tissue confirms this condition. 
Coincident with these changes in form and size there is a 
corresponding change in the character of the tissues comprising 
the walls of the tract in this region. The muscular tissue degen- 
erates, the tunica likewise grows thin and in places entirely dis- 
appears, leaving only the lining epithelium connected by slight 
strands of connective and mucous cells. It should be noted in 
this connection that these changes are restricted for the most 
part to the region of the abdominal tract, the walls of the crop 
retaining more of less clearly their normal histological features. 
But the most distinctive aspects of this metamorphosis is 
shown in the cytological changes which accompany it. The 
epithelium which in the larval enteron is quite typical shows 
undoubted degenerative characters. Globules of oil appear here 
and there in the cells, becoming more abundant with the age of 
the insect, until the cells become literally packed with these fat 
globules. Associated with this condition are no less evident signs 
of degeneracy in the amitotic division of the cells and in their 
multinucleate condition in many cases. 
Moreover, in many cases the nuclei showed the presence of 
vacuoles of varying shapes and size, and in certain of these could 
