_Osmia bennettæ._ Ckll. Det. Ckll. Mountains near Claremont, Cal., Baker. _Osmia integra._ Ckll. Det. Ckll. Claremont, Cal., Baker. _Osmia cobaltina._ Cr. Det. Ckll. Claremont, Cal., Baker. May, Lotus glaber. _Osmia faceta._ Cr. Det. Ckll. Claremont, Cal., Baker. _Osmia clarescens._ Ckll. Det. Ckll. Claremont, Cal., Baker. April, Fl., Phacelia tanacætifolia. _Osmia granulosa._ Ckll. Det. Ckll. Claremont, Cal., Baker. _Osmia regulina._ Ckll. Det. Ckll. Mountains near Claremont, Cal., Baker. _Osmia ednæ_, female. Ckll. Det. Ckll. Mountains near Claremont, Cal., Baker. _Osmia playtura._ Ckll. Det. Ckll. cotype. Claremont, Cal., Baker. _Osmia hypochrysea._ Ckll. Det. Ckll. Claremont, Cal., Baker. _Osmia pumila._ Frieze Det. Cr. Claremont, Cal., Bray. May, Fl. Mustard. _Osmia cyanopoda_ sp. n. Ckll. Det. Ckll. Claremont, Cal., Baker. _Osmia cyanosoma._ Ckll. Det. Ckll. Claremont, Cal., Baker. _Osmia nigrobarta_ sp. n. Ckll. Det. Ckll. Claremont, Cal., Baker. _Hoplitis sambuci._ Titus Det. Ckll. Claremont, Cal. April, Poppy. _Hoplitina pentamera._ Ckll. Det. Ckll. Claremont, Cal., Baker. _Osmia pogonigera._ Ckll. Det. Ckll. Claremont, Cal., Baker. _Alcidamea hypocrita._ Ckll. Det. Ckll. Claremont, Cal., Baker. _Osmia melanopleura_ sp. n. Ckll. Det. Ckll. Claremont, Cal., Baker. _Anthidium maculoscum._ Cr. Det. Cr. Claremont, Cal., Baker. _Dianthidium illustri._ Cr. Det. Ckll. Claremont, Cal., Baker. _Anthidium palliventre._ Cr. Det. Br. from Coll. Claremont, Cal., Baker. _Anthidium tricuspidum._ Prov. Det. Ckll. Claremont, Cal., Baker. _Dianthidium consimile._ Ashmead Det. Ckll. Claremont, Cal., Baker. _Dianthidium robertsoni._ Ckll. Det. Ckll. Mountains near Claremont, Cal., Baker. _Anthidium angelarum._ Titus Det. Ckll. Claremont, Cal., Baker. _Dianthidium provancheri._ Titus Det. Ckll. Claremont, Cal., Baker. _Dioxys producta._ Cr. Det. Ducke. Claremont, Cal., Baker. _Dioxys pomonæ._ Ckll. Det. Ckll. Claremont, Cal., Baker. _Coelioxys megatricha_ sp. n. Ckll. Det. Ckll. Claremont, Cal., Baker. _Coelioxys angulifera_ sp. n. Ckll. Det. Ckll. Claremont, Cal., Baker. _Xenoglossa angelica._ Ckll. Det. Ckll. Claremont, Cal., Baker. ANDRENIDÆ _Andrena porteræ._ Vier. Det. Ckll. Claremont, Cal., Baker. _Andrena mustelicolor._ Vier. Det. Vier. Claremont, Cal., Baker. _Andrena prunorum._ Vier. Det. Ckll. Claremont, Cal., Baker and Bray. May, Phacelia tana. and Poppy. _Andrena mimecta._ Ckll. Det. Ckll. Mountains near Claremont, Cal., Baker. _Andrena texana._ Cr. Det. Br. from Coll. Claremont, Cal., Bray. May, Fl., Poppy. _Andrena bipuntala._ Lovell Det. Br. from Coll. Claremont, Cal., Bray. April, Fl., Phacelia tan. _Andrena cerasifolii._ Vier. Det. Ckll. Claremont, Cal., Baker. April, Phacelia tanacætifolia. _Andrena carlina_ Ckll. Ashmead Det. Br. from Coll. Claremont, Cal., Bray. May, Fl., Mustard. _Andrene osmoides_ sp. n. Cr. Det. Ckll. Claremont, Cal., Baker.