196 CALIFORNIA ACADEMY OF SCIENCES. 



between the segments of the body and the joints of the 

 legs; i. e., the parts are continuous but non-chitinized 

 where the articulation occurs. 



Goniodes cervinicornis. (Plate XIV, fig. 2). 



The penis can be protruded for a distance about equal 

 to three segments of the abdomen. The outer part con- 

 sists of a delicate membranous tube evaginated from 

 the inner end of the genital chamber. It is protected 

 by three chitinous processes arising from a circular 

 chitinization surrounding the base of the membranous 

 penis. Two of the processes are lateral, long, slender, 

 tapering, and somewhat convergent, with the outer edges 

 convex and the inner concave. The third is ventral 

 and median. It is a narrow chitinous rod having the 

 distal end triangularly expanded, terminating some 

 distance in front of the posterior ends of the lateral 

 processes. These parts are free from the wall of the 

 membranous penis but closely surround it. Lying 

 within the dorsal wall of the latter is a thin, wide, chitin- 

 ous plate arising also from the circular chitinous base 

 of the penis. It is shorter than the ventral process, 

 and has its edges a little concave. From the anterior 

 ventral margin of the basal part of the external penis 

 a large, thin, parallel-sided, chitinous plate, having a 

 rounded anterior edge and slightly concave lateral edges, 

 arises and passes forward within the body-cavity, giv- 

 ing attachment to protrusor and retractor muscles. 

 It lies close to the ventral wall of the body-cavity, and 

 at its base the ejaculatory duct enters the external penis. 

 The opening into the latter is overhung by a wide tap- 

 ering plate. The membranous penis extends beyond 

 the ends of all tiie chitinous parts. When the chitin- 

 ous structure is pushed outwards the outer processes 



