OF WASHINGTON. 



241 



characters in each particular case, and should not be led to 

 generalize from isolated structural characters. He brought up 

 certain allied instances among the fishes. Dr. Stiles spoke of 

 the number of hooks on the head of the Taeniida3. 

 Mr. Marlatt read the following paper : 



THE HEMIPTEROUS MOUTH. 

 By C. L. MARLATT. 



The hitherto accepted idea of the structure of the mouth of 

 hemipterous insects has been called in question by Prof. J. B. 

 Smith, and an explanation offered which entirely overturns the 

 old conceptions of the homologies of the mandibular, maxillary, 

 and labial structures of these insects.* Some observations which 



FIG. 21. Head and prothorax of Cicada, lateral view, showing parts 

 in normal position (original). 



I had made on the feeding habits of aphides, without particular 

 reference to mouth structure, led me to make a general study of 

 the hemipterous mouth. It very soon became apparent that 

 Prof. Smith had been led into an error, doubtless through an 



* Science, April I, 1892, pp. 189-190. 





