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Illinois Natural History Survey Bulletin 



Fol. 23, Art. 1 



base to the middle, the ventral margin with 

 a short apical projection and a longer digi- 

 tate subapical projection, the apico-dorsal 

 portion evenly rounded. Tenth tergite semi- 

 membranous, with a basal carina. Claspers 

 with a small and digitate dorso-lateral lobe 

 and with the ventro-mesal lobe subdivided 

 into three staggered tubercles, each bearing 

 a seta of medium length, the mesal one the 

 stoutest. Above the claspers is a beaklike 

 ventral projection, the central part wide 

 and bearing a pair of sharp setae. Aedeagus 

 similar to that of ponta, consisting of a small 

 conical base, a long, tubular central portion 

 and a threadlike apex, as in fig. 930C. 



Holotype, male. — San Felipe Springs, 

 Del Rio, Texas: April 19, 1939, H. H. & 

 J. A. Ross. 



Hesperophylax Banks 



In this genus the ranking of various 

 described species and varieties has varied 

 considerably with different authors, at times 

 all of them being considered forms of a 

 single species. Detailed study of the geni- 

 talia of both males and females indicates 

 that, in the material at my disposal, five 

 species can be segregated definitely; the 

 differences are comparative structures of 

 the male genitalia and, where associated ma- 

 terial is available, in the genitalia of the 

 females, also. I have seen no material of 

 minutus nor definitely associated females 

 of magnus and consimilis. With the excep- 

 tion of these forms, the following key will 

 separate the North American species. 



932 A 



CONSIMILIS 



933 A 



MAGNUS 



935 B 



DESIGNATUS 



935C 



936 A 



INCISUS 



936 B 



Figs. 932-936. — Hesperophylax, male genitalia. J, lateral aspect; B and C, tenth tergite, 

 respectively lateral and caudal aspects; D, aedeagus. 





