NO. lO 



MORPHOLOGY OF GNATIIOTRICHUS SCIIEDL 



59 



The penis presents, in the genus Gnathotrichus, excellent generic as 

 well as specific characters. The following discussion is based on 

 slides which were made from dried material treated with io% sodium- 

 hydroxide solution. Dr. Fuchs distinguished two layers of covers, the 

 outer and the inner. These two layers were also found to be present 

 in Gnathotrichus. The outer layer consists of a membranous tube 



Fig. 32. — A, Gnathotrichus stilcattts Lee; B, Gnathotrichus rctusus Lee; C, D, 

 Gnathotrichtts materiaritis Fitch. : A, B, C, lateral aspect ; D, dorsal aspect. 



Ca, caput; Fep, femora penis; Lad, laminae dorsales; Lav, laminae ventrales; Mc. metula; 

 Pal, pallidium; Pa, parameren; Prp, preputial sac; Ro, rostrum; a, ventral nob of the 

 parameren; b, tegmen furcae; c, internal ridge on Lad. 



in which the inner cover slides forward and backward. A ringlike 

 part of this tube is heavily chitinized, and when dried specimens are 

 used only this structure is obtained. It was called by Lindeman the 

 gabel, the parameren l)y \>rhoeft' and the tegmen by Hopkins. The 

 inner cover consists of a second tube which is heavily chitinized 

 throughout and which shows remarkable variations from species to 

 species. Figure 2)-^ illustrates the peni of the genus under exami- 

 nation. 



