268 GEO. n. HORN, M. D. 



From the abovfe list it will be seen that 60 specimens have been 

 observed, 53 % and 7 $ , with several others too mutilated to be 

 safely made use of. The table shows the relative frequency of the 

 sexes. Of the 53 males 24 have four abdominal segments visible, 

 29 have five segments. Of the females 5 have four segments and 2 

 have five. Thus the value of the number of segments in determin- 

 ing the sex of our species is completely disproved by the statistical 

 arrangement of the specimens. 



Another point in connection with this is a comparison of the 

 European species with our own on other characters. Of the twenty- 

 four species included in the admirable monograph by TournieV, twenty- 

 two have the posterior thighs of the male variably dentate, one only 

 has simple thighs and of one the male is unknown. In the preceding 

 list of our species five (Jjidentatnm is probably introduced and not 

 counted at this time), have dentate thighs and seven simple thighs. 



Reverting to the table all the males with dentate thighs have five 

 abdominal segments and the only known female four. The last seven 

 species with the posterior thighs simple, a series in which we greatly 

 exceed the European number, we have ten males with five segments 

 and seventeen with four, and in the fem.iles four have four segments 

 and two have five. 



From the evidence afi"orded by our own material it is highly proba- 

 ble that Tournier's statement is entirely correct for the European 

 species and not at all true for those peculiar to our fauna. 



The antennal club varies in length and thickness and apparently 

 in the number of joints composing it. In the following pages the 

 club is for the most part called •' four-jointed," but in several instances 

 the seventh joint is so much larger than the sixth and approximates 

 more closely in size to the eighth that the club is then called " five- 

 jointed." 



The study of the species beyond this point is an extremely difficult 

 one and males only can be determined with certainty even by com- 

 parison, fortunately they are more abundant. 



The following table will assist the student in the determination 

 of the species : 



Anterior tarsi of male slender, not at all dilated. Posterior femora of male 

 toothed near the apex. 

 Posterior tibiae distinctly arcuate, an obtuse tooth near the knee. 



bidcntatum Sahib. 



Posterior tibiae feebly arcuate and slightly narrowed at the knee, without 



tooth paradoxum n. sp. 



