52 
manner and times of taking food, whether the adult ever feeds, 
whether both sexes are alike in this respect, nature of the food 
of the larva and pupa, ete. Into these phases it is not the purpose 
of the present paper to enter. The more particular purpose is the 
presentation of the observations made upon the morphology of 
the enteron of the adult as compared with the larva and pupa and 
some suggestions as to the probable functions of the several 
regions. 
It has been a more or less current opinion for many years 
that the adult Cicada takes no food, and that therefore the enter- 
on is, as a result, more or less rudimentary. During the occur- 
rence of the insect here, occasion was taken to submit specimens 
to the class in zoology for dissection as a part of the regular 
course of laboratory work. Unusual difficulty was encountered 
by students in securing anything like satisfactory demonstrations 
of the alimentary system, and in many specimens anomalous cay- 
ernous spaces were found in the abdominal region, in some cases 
the entire region appeared to be little more than a thin shell-like 
structure comprising hardly more than the body walls. The sub- 
ject seemed sufficiently interesting to call for further attention 
and members of the senior class were asked to undertake a de- 
tailed study of both the general morphology and histology of the 
tract, the results of which I have since reviewed with more or less 
care. 
An examination of such literature as has been available fails 
to show any work of consequence upon the subject. Marlatt in 
his recent monograph refers to the adipose matter stored in the 
tissues as a probable source of food during adult life but gives no 
specific evidence in support of the suggestion. 
The careful dissection of a large number of specimens 
showed only in two or three cases a continuous enteron from 
mouth to anus such as may be traced in the early larva. This 
degeneration, or atrophy, first shows itself in the pupa stage 
where the tract becomes more or less rudimentary in the posterior 
portion, the entire abdomen becoming packed with adipose mat- 
ter from which oil droplets exude upon dissection of the insect. 
On emergence from the pupal skin there seems to be almost com- 
