8o 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 1 37 



2Tar Ar 



Fig. 13. — Hind leg of MarelUa remipcs (female). 



A, right hind tibia and apical portion of femur, dorsal view. B, riglit hind 

 leg, lateral (anterior) view. C, apical portion of right hind tibia and tarsus, 

 ventral view. 



Ar, arolium ; Cx, coxa ; Fni, femur ; h, fringe of hairs in the inner margin of 

 the apical portion of tibia ; Tar, tarsus ; Tb, tibia ; TP, tarsal pulvilli ; Tr, 

 trochanter ; TSr, tibial spurs ; Un, claws. 



ventral sides are strongly convex transversally. Each spur ends in an 

 acute upwardly directed point, which bears a tuft of stiff bristles on 

 its ventropnsterior surface. 



In the rearward stroke of the motion of swimming, the tibial spurs 

 serve as supports for the dilated hind tarsi, keeping them from being 

 bent down by the resistance of the water. The tarsi are freely mov- 



