COLEOPTERA OF BAJA CALIFORNIA. 253 



Tarsi black with a ring of whitish pubescence at the base 

 of each joint. Length, .40 inch; 10 mm. 



Male. Antenna setaceous the first joint as long as the 

 next two, not sinuate at apex, second three-fourths as long 

 and equal to the next three joints together. Anterior 

 tibiae with two terminal spurs, the first joint of tarsi longer 

 than the second. Last ventral segment incised. 



This species resembles linearis very closely and it is 

 probable that the females will be difficult to separate. 



San Jose del Cabo. 



At the time of my study of Macrobasis (Proc. Amer. 

 Philos. Soc. 1873) the male of linearis was unknown. 

 The following are the sexual characters which will sepa- 

 rate it from langiiida : 



M. linearis ^ Lee. Antenna setaceous, the first joint 

 as long as the next five not sinuate at tip, second joint 

 scarcely a third of the first. Anterior tibi^ with a single 

 spur, first joint of tarsi much shorter than the second and 

 strongly compressed at base. 



Otidocephalus alternatus n. sp. 



Form of vittatus, piceous black, shining, clothed with 

 recumbent and not dense gray hairs the alternate inter- 

 vals of the elytra naked, without erect setae. Rostrum 

 smooth in front, not carinate, punctate at the sides. Tho- 

 rax elongate oval, one-half longer than wide, equally nar- 

 rowed at apex and base, regularly convex, coarsely not 

 closely punctate. Scutellum densely clothed with white 

 pubescence. Elytra elongate oval, widest at middle, hu- 

 meri well marked. Punctures in striae rather coarse and 

 closely placed, intervals slightly convex, intervals 2-4- 

 6—8 moderately densely pubescent, the others sparsely 

 biseriately punctate, each puncture with a hair. Body 

 beneath sparsely hairy, a denser line at the sides of meso- 

 and metapectus. Legs brownish, sparsely punctate and 



