Sept., 1903.] 



SwENK : Synopsis of Japyx. 



131 



the second tooth concave with many ; left arm with a large tooth one third 

 its length from the base, proximally from which are three smaller denti- 

 cules and distally from it nine feebly marked denticules. 



Japyx americanus MacGillivray (West-central Washington). 



Right arm with a single broad based, sharp tooth about one fourth the length 



of the arm from the base, distally from which is a large abruptly inwardly 



deflexed sinus, interrupted by four smaller, widely separated denticules ; 



left arm similar to right Japyx minimus, sp. nov. 



(Southeastern Nebraska). 



With enlarged dorsal view of their forceps. 



Japyx minimus, sp. nov. 



Head ijuadrangular, transverse, about one fourth longer than broad ; anfenn<e 

 short, eighteen-jointed, the segments subcylindrical, and gradually decreasing in 

 size apically. Prothorax about two thirds as broad as the head, longer than broad, 

 and truncate in front. Abdomen with first seven segments rounded at the sides, the 

 second slightly larger than the others, of which the seventh is slightly the smallest. 

 All are without emargination. The last three segments have straight, almost parallel 

 sides, the eighth wi'h the anterior end concave, the posterior end convex and articu- 

 lating with the concave anterior end of the ninth segment ; this one in turn articulates 



