34 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



middle, the sides being moderately convex and rounding in well mesad 

 at anterior ends. 



Head about equal in length and breadth; suborbicular with the 

 sides strongly convexly bulging caudad of the ocelli. A rather deep 

 transverse sulcus a little in front of caudal edge and two pairs of longi- 

 tudinal sulci diverging cephalad from this transverse furrow. 



Ocelli large; bluish. 



Antennae long; extending to or beyond the middle of the body; 

 strongly attenuated distad. Articles 41; of these the first fourteen 

 are relatively more compact as in dolichopus, etc., but the transition 

 to the relatively slender and more loosely joined articles more gradual 

 than usual; beyond the fourteenth article shorter articles recur in pairs 

 in the ordinary way, the last six, however, all being of the longer type. 



Prosternum twice as wide as long. Teeth very small or almost 

 obscure; 3+3. Margin on each side meeting its mate at very obtuse 

 angle, a mesal incision being scarcely developed. 



Posterior angles of seventh, ninth, eleventh, and thirteenth dorsal 

 plates strongly produced; angles of the last three long and acute, 

 while those of seventh have caudal side long and convex, the mesal 

 portion of the plate being deeply incurved. Dorsal scuta strongly 

 arched, with the caudal and lateral borders depressed as usual; each 

 plate with a pair of distinct longitudinal sulci with outside of each 

 one of these a second shorter and more or less divergent sulcus. 



Anterior ventral plates broadly depressed from edges to middle. 

 Most plates with indications of three longitudinal sulci of which one 

 toward each side is more distinct than the median. A transverse 

 furrow a little in front of caudal margin especially distinct; one or 

 two more anterior ones present which are less so. 



Legs all long with their tarsi conspicuously slender as usual, con- 

 siderably more so than the tibia which, in turn, is abruptly more 

 slender than the femur. Prefemoral and tibial processes as usual. 



Porigerous area of coxa deeply depressed, with the edges well chiti- 

 nized. Pores circular; about 3, 3, 4, 4, 4, to 4, 4, 4, 4, 4 in number and 

 arrangement. 



Claw of female gonopods entire, long and strongly curved, acutely 

 pointed. Spines as usual, acutely attenuated from base distad; of 

 but moderate stoutness. 



Length 14.5 mm.; antennae 8 mm. long; width of eighth dorsal 

 plate 2.1 mm. 



LOCALITY. British Columbia (Powder Creek, Kaslo!). 



The single type is a female. 



