No. 464]  OCELLUS OF THE ADULT INSECT. 643 
the front), while the other two are seen in the front, a little 
below the antenna. 
This peculiar appearance of the four spots led me to investi- 
gate the occurrence of the original four ocelli. In deciding 
this question I have made several microtome sections and 
stained them by the various methods. The preparations have 
not only shown the connection of the nervous system with 
these four spots, but their histological characters threw a light 
upon the nature of their origin as the optical organs. 
The complete account of my studies on this subject, with 
some illustrations, may be published in the near future ; there- 
fore I shall leave only the preliminary statement here for the 
present. 
CORNELL UNIVERSITY, ITHACA, N. Y., 
une IO, 1900. 
