354 W. D. FUNKHOUSER 



genital apparatus, are not adaptable to the Membracidae, since in this 

 family the tip of the abdomen not only is generalh^ concealed by the 

 posterior process of the pronotum but is often folded entirely within 

 this structure. Since the pronotum is strongly chitinized and very rigid, 

 and since the abdomen is not long enough to be extended beyond or pulled 

 below this covering, the examination of the genital apparatus is, in a 

 large number of species, rendered decidedly difficult if not impossible. 



Nevertheless there are a number of reasons why the anatomy of the 

 genital organs should be worked out and their taxonomic importance noted. 

 In the first place, the known usable taxonomic characters of the Mem- 

 bracidae are extremely limited and any additional data on the subject 

 are of great value. Again, there are many forms that lack the heavy 

 posterior pronotal process, and in these the apex of the abdomen may be 

 easily studied. Moreover, even in forms in which the abdomen is partly 

 covered, it might often be possible to discern the particular characters 

 necessary for diagnosis when all others are obscured. And finally, if the 

 genital character gave absolute evidence it might often bo worth while 

 to dissect one specimen of a series in order to establish the validity of other 

 specimens. For these reasons the structure of the male genitalia is here 

 discussed in some detail in order that it may serve as a basis for more 

 extended work on the subject. The actual value of such data can, of 

 course, be known only when comparison is made of a large mnnber of 

 genera. Such a task is beyond the scope of this study, but the resultant 

 data are much to be desired. 



The literature relating to the structure of male genitalia in Hemiptera 

 is very meager and the work done has been in rather widely separated 

 families. Of the published works on the subject, the short report by 

 Bliimml (1899) on the Psyllidae shows conditions which more nearly 

 approach those of the Membracidae than have been noted in any other 

 family of Hemiptera. This bears out Crawford's (1914:16) suggestion 

 that the relation of the psyllids to the Cicadidae and the Membracidae 

 is probably close. The psyllids show, however, an arrangement of genital 

 parts which, while homologous, is not strictly comparable to that of the 

 membracids. The fact that the workers in various groups have been 

 more or less independent of one another in the matter of terminology 

 has resulted in a slight confusion of terms; but, since the structure of the 

 membracid organs is comparatively simple, this subject needs no dis- 



