356 BULLETIN 129, UNITED STATES NATIONAL MUSEUM 



narrow and formed of seven articles. Straight, stiff hairs border the 

 antennae and are arranged in a series of tufts on the pterygostomian 

 regions. 



An American genus, ranging from Beaufort, North Carolina, to 

 Cape St. Roque, Brazil, and from Magdalena Bay, Lower California, 

 Mexico, to Panama and the Galapagos Islands. . 



KEY TO THE SPECIES OF THE GENUS PITHO 



A'. Second and third lateral teeth, exclusive of tooth at orbital angle, partially 

 united at base. 

 B'. First movable segment of antenna much wider than long, its outer lobe 

 strongly produced laterally. Lateral teeth of carapace blunt-tipped 



in the adult aculeata, p. 357. 



B^. First movable segment of antenna little, if any, wider than long, its outer 

 lobe produced as much anteriorly as laterally. Lateral teeth of cara- 

 pace acute. 

 C. Lateral teeth subequal in size. Carapace subcircular, front narrow. 



laevigata, p. 372. 

 C^. Lateral teeth not subequal. 



D^ Last two lateral teeth not much, if any, smaller than the others. 

 E'. Carapace strongly tuberculate. Second lateral tooth smaller, but 



not much smaller, than first and third picteti, p. 359. 



E^. Carapace nearly smooth. 



F'. Second lateral tooth very small, much smaller than first and 



third teeth anisodon, p. 368. 



F^. Second lateral tooth of considerable size, slender. 



laevigata, variety, p. 373. 



D^. Last two lateral teeth much reduced, at least in male. Manus of 



adult male broad, compressed. 



E'. First movable segment of antenna slightly' wider than long. Lateral 



teeth sharper in female than in male, the last two teeth more 



prominent than in male Iherminieri, p. 362. 



E^. First movable segment of antenna longer than wide. Fourth 

 lateral tooth subequal to first three in female, fifth tooth smaller. 

 Fourth and fifth teeth much reduced in male. 



quinquedentata, p. 361. 

 A^. Second and third lateral teeth not united at base. 



B*. More than four lateral teeth. Carapace conspicuously granulated. 



C^. Lateral teeth five (exceptionally four), dentiform, their ^dges denticu- 

 late mirabilis, p. 366. 



C^. Lateral teeth six, spiniform sexdentata, p. 367. 



B^. Four lateral teeth or spines. 



C. Lateral teeth long and narrow, spiniform. Rostral teeth acutely 



pointed quadridentata, p. 369. 



C^. Lateral teeth short and broad. Rostral teeth arcuate or very obtuse- 

 angled dispar, p. 374. 



ANALOGOUS SPECIES ON OPPOSITE SIDES OF THE CONTINENT 



Pacific 

 aculeata. 

 Iherminieri. 

 mirabilis. 



Atlantic 

 picteti. 



quinquedentata. 

 sexdentata. 



