THE WATER SCORPIONS. 



1035 



ward apex, armed beneath in front of middle with one or two 

 blunt teeth, the apical third grooved and finely fimbriate for 

 the reception of the much shorter curved tibiae and rigid single- 

 jointed tarsi ; middle and hind legs very slender, the hind tarsi 

 longer than femora ; abdomen carinate beneath along the mid- 

 dle; abdominal tube two-thirds or more the length of elytra, 

 protected at base by a shield formed by a prolongation of the 

 sides of last dorsal. 



Fig. 2n7. a, Nepa apiculata Uhl., X 1.7 ; b. ventral view of head of Ranatra 

 showing antenna^ (A) in repose; c and d, antennae of Ranatra kirkaldyi Bueno, the 

 terminal segments fused in c, separate in d ; e, antenna of R. nigra H.-S. ; /, same 

 of R. fusca P. B. (After Hungerford ) . 



The genus is represented throughout the world, about 20 

 species being known from America, eight of which occur in this 

 country, six in our territory. The synonymy of our species is 

 very much confused and will never be correctly determined 

 with certainty until the types of the R. fusca of Palisot-Beau- 

 vois and the R. nigra of Herrich-Schaeffer are studied in con- 

 nection with those of Montandon and others. I have adopted 

 the conclusions of Hungerford (1923b) in the nomenclature 

 which follows. 



KEY TO EASTERN - SPECIES OF RANATRA. 



Front femora broad, stout, not constricted near middle and usually 

 without a preapical tooth or sinuation (fig. 208, b) ; second joint 

 of antennae simple, without a branch or prolongation on side (fig. 

 207, c and d) ; length of body, 23 — 30 mm. 1175. kirkaldyi. 



Front femora more slender, distinctly narrowed in front of the sub- 

 median tooth; second joint of antennae with a branch or prolonga- 

 tion on side (fig. 207, e and /) . 



