222 U.S. NATIONAL MUSEUM BULLETIN 261 



validate lectotypes recently selected by me, and a check list of the 

 described species. 



ONCOMETOPIA, sensu stricto 



Figures 207-215 



(See generic heading, p. 220, for synonymy.) 



Species as in the description for Oncometopia, Stil, s.l., above, and 

 with the tenth abdominal segment (base of anal tube) of the male not 

 modified to form conspicuous large lobes. Geographic distribution as 

 in generic description. 



The common widespread North American species of Oncometopia, 

 S.S., is or bona (Fabricius). As with a number of other species, it has 

 a considerable range of variation in the form of the aedeagus (fig. 207). 

 This species extends from north-central and northeastern United 

 States to the Gulf Coast in its western range and to the region of tlie 

 Okefenokee Swamp in the eastern part of its range. A second species 

 occurs throughout Florida, except in the extreme northern portion; 

 the aedeagus of this species is illustrated in figure 211. This Florida 

 species agrees with 0. nigricans (Walker), of which I have examined 

 the type. Diflferences between these two forms were also found in 

 sclerites in the female genital chamber (figs. 208j and 210), which 

 Nielson (1965a) interprets as sternal elements of abdominal sternum 

 VIII (the sclerotization of the female genital chamber of 0. nigricans 

 (Walker) is like the illustration (fig. 210) of 0. clarior (Walker)). Dr. 

 W. F. Turner, upon learning of these differences through correspond- 

 ence with me, collected a form now known to occur in northern Florida 

 and southern Georgia, which is intermediate in both male and female 

 characters (fig. 209) . Dr. Turner tried crosses between the northern and 

 southern forms, but none with the intermediate forms. The attempts 

 were unsuccessful. My assessment of the status of the forms is that three 

 species are involved: 0. orbona (Fabricius) in northern and north 

 central United States, 0. nigricans (Walker) in Florida and southern 

 Georgia, and an unnamed species in northern Florida and in southern 

 Georgia; although there is a possibility that a step-cline is involved and 

 that all three forms belong to the same species. Cross-breeding experi- 

 ments between the northern and intermediate and between the 

 southern and intermediate forms are needed to solve this problem. It 

 will be noted that the present interpretation of the Florida species does 

 not agree with that of Schroder (1959a: 17) who illustrated, as nigricans, 

 the aedeagus of a species of which I have examined specimens from 

 Victoria, Texas, from Vera Cruz, Mexico, and from Guatemala, but 

 not from Florida. 



