Two new species, Diastylis newberryi and Diastyloides pacifica, are described, based on specimens collected off the coast of California. Diastylis newberryi is a problematical species, falling between the definitions of the genera Diastylis Say, 1818 and Leptostylis Sars, 1869, but can be identified by the unique combination of a single pair of lateral setae on the telson, male first antenna not greatly expanded, and male second antenna extending past the pleon. Diastyloides pacifica is the first species of the genus to be collected outside the North Atlantic basin.