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ENTOMOLOGICAL SOCIETY 



ing from the inner surface of the clypeus and labrum, and the 

 hypopharynx, projecting from the inner face of the base of the 

 labium. A more detailed description of these parts follows. 

 For the careful drawing illustrating the studies and for very ma 

 terial aid in working out details of structure, I am indebted to 

 Miss Lillie Sullivap. 



Clypeus. In the cicada the clypeus (I a) is enormously en 

 larged, and forms the bulk of the anterior portion of the head, 

 extending from the base of the antennae to the labrum. Exteri- 



FIG. 22. Head of Cicada, front view, showing the normal position of mouth- 

 parts on the left, and with the mandible and maxilla drawn out on the 

 right (original). 



orly it is ornamented with a number of parallel grooves, arranged 

 in two longitudinal rows. 



Labrum. This sclerite (I b, c] is attached to the anterior 

 edge of the clypeus and is triangular in shape, truncated at the 

 apex with the anterior angles bent under, and developed into a 

 projecting, sheath-like appendage (I c, and I' c Fig. 23) which 

 covers the base of the labrum and closes over the bases of the setaB. 



Mandible. Viewing the head laterally, a small elongate 

 sclerite (II a) is seen extending from near the base of the com- 



