1922] Kershaiv and Miiir: Genitalia of Homoptera 209 



The more common form of this subtype is found among the 

 Cixiidas (i. e., Oliarus), where the periandrium forms a fairly 

 long tube more or less chitinous and often bearing large spines 

 and other processes, the penis is often complex and produced 

 into processes and more or less membranous so that the con- 

 junctiva is not sharply defined; the penis apodeme passes 

 through the periandrium and joins the base of the penis. The 

 following f amiHes have this subtype : Tettigometridse ; Cixiid^ 

 in part; Delphacidae in part; Tropiduchidae in part; Derbidas 

 modified. 



In the Flatoid subtype the periandrium is shorter and 

 wider, and generally funnel shape and the penis is invaginated 

 into the periandrium and is also often funnel shape. Both the 

 periandrium and the penis often form a short tube or ring 

 bearing lateral processes. The complexity is very great in 

 some forms (i. e., Capeloptcriim macidifrons, Issidee). The 

 Meenoplin£e of the Cixiid^ come under this type and thereby 

 add one more character by which they approach the Flatidae. 

 The following families have this type of sedeagus: Flatidae, 

 Acanaloniidas, Ricaniidas, Issidae, Dictyophoridae, Fulgoridse, 

 Achilidas, Eurybrachidae, Lophopidae and Cixiidae in part. 



The Delphacoide subtype contains Delphacidce in part and 

 Tropiduchidae in part. In it the periandrium is greatly reduced 

 or absent and the penis alone forms the aedeagus and is generally 

 tubular. The periandrium generally forms a small ring at 

 the base of the aedeagus and is joined by a chitinous structure 

 to the base of the anal segment. 



FURTHER SPECULATIONS. 



We consider that the facts briefly stated in this paper are 

 sufficient to demonstrate the homology between the genitalia of 

 the two sexes, and between the Fulgoroidea and the Cicadoidea. 

 There is much work still to be done in all the groups, especially 

 in the Fulgoroidea where the variation in detail, especially 

 in the aedeagus, is very great. Exactly what becomes of the 

 ninth sternite has yet to be shown, also the nature of the area 

 between the aedeagus and the anal segment. 



Turning to other orders we find that the Lepidoptera and 

 Trichoptera appear to be built upon the same morphological 

 plan as the Fulgorids. There is a ring-like segment which 



