THE KANSAS UNIVERSITY 



SCIENCE BULLETIN 



Vol. XIV.] October, 1922. [No. 8. 



The Ovipositors of the CicadelUdae (Homoptera) . 



By PHILIP A. READIO. 



.•^iihniitted to the department of entomology and to the siaduHte faculty of the University 

 of Kansas in partial fulfillment of the requirements for the degree of master of science, 

 May 1.'), 1922. 



INTRODUCTION. 



THE primary purpose of this paper is to determine whether or 

 not the ovipositors of the Cicadelhclse possess characters of 

 value in classification, and if so, of how much value these characters 

 are and how accessible they are to the general worker. To Prof. 

 Paul B. Lawson belongs the credit for suggesting the paper. In the 

 same group he has recently found that the male genitalia are of 

 much value in classification, and the possibility of equal value in 

 the female genitalia occurred to him. Miss Itasca Hilsman, work- 

 ing in the closely related family, Cicadidse, found that the ovi- 

 positors in this group "afford constant and ready characters which 

 may at times be of decided value to him (the specialist) in the de- 

 termination of closely related species." Hence it was natural to ex- 

 pect that equally favorable results might be obtained from a study 

 of the ovipositors of the Cicadellidse. As an introduction to the 

 taxonomic part of the paper, a morphological study of the abdomen 

 of the female and the structure of the ovipositor was made. 



In addition to the reasons already stated, there are certain gen- 

 eral considerations which would lead one to expect such an investi- 

 gation as this one to be fruitful. It is constant characters that the 

 taxonomist is in search of — characters that are sufficiently definite 

 to separate closely related species, and yet are present in tlie entire 

 range of the species. Because of their internal position, genitalia 

 are more likely to be constant than external structures, which may 

 vary with differences of environment. The constancy of the use to 

 which genitalia are put also makes for the permanency of their 

 structure and their usefulness as taxonomic characters. 



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