GENERAL INTRODUCTION. 



19 



The epistome covers the base of the tongue. When normal 

 it has a thin mesial lobe and a large process at each side. 

 The lateral processes are designated " pilifer " by Kellogg. 

 The normal pilifer (p) is a curved obtuse process, concave 

 and flattened on the inner side, and is beset on the inner 

 surface with a great number of long stiff bristles which project 

 over the base of the tongue, which they touch. 



ig. 5. — Morphology of head. 



A. Head of Psilogramma menephron, denuded, dorsal view. A, base 



of antenna ; gp, genal process ; It, labrum ; mxp, maxillary 

 palpus ; p, pilifer ; t, tongue. 



B. Head of Psilogramma menephron, denuded, ventral view, labial 



palpi removed, flp, groove in which labial palpus is inserted ; 

 other lettering as in A. 



C. Mouth-parts of Psilogramma menephron, lateral view. Lettering 



as in A. 



D. Head of Cechenena lineosa, frontal aspect. 



E. Head of Cechenena lineosa, lateral aspect, gr, cavity of first segment. 



The genal process (gp) is a more or less triangular projection 

 between the pilifer and eye, supporting the former laterally. 

 It is an enlargement of the brim which separates the eye 

 from the large labial cavity of the underside of the head. 



c2 



