| Agapostemon (Agapostemon) angelicus Cockerell, 1924 | |
| Agapostemon (Agapostemon) femoratus Crawford, 1901 | |
| Agapostemon (Agapostemon) melliventris Cresson, 1874 | Honey-bellied Agapostemon |
| Agapostemon cockerelli (Crawford, 1901) | ⇒ Agapostemon obliquus Provancher, 1888 |
| Ammophila kennedyi Murray, 1938 | |
| Ancylandrena larreae Timberlake, 1951 | Creosote Bush Ancylandrena |
| Andrena (Andrena) frigida Smith, 1853 | Frigid Andrena |
| Andrena (Belandrena) palpalis Timberlake, 1951 | |
| Andrena (Callandrena) helianthi Robertson, 1891 | Sunflower Andrena |
| Andrena (Callandrena) melliventris Cresson, 1872 | Honey-bellied Andrena |
| Andrena (Callandrena) pecosana Cockerell, 1913 | |
| Andrena (Cnemidandrena) chromotricha Cockerell, 1899 | Pigmented Miner Bee |
| Andrena (Cnemidandrena) colletina Cockerell, 1906 | |
| Andrena (Cnemidandrena) surda Cockerell, 1910 | |
| Andrena (Dasyandrena) cristata Viereck, 1917 | Yellow screwstem |
| Andrena (Holandrena) cressonii Robertson, 1891 | Cresson'S Mining Bee |
| Andrena (Micrandrena) microchlora Cockerell, 1922 | |
| Andrena (Micrandrena) piperi Viereck, 1904 | |
| Andrena (Plastandrena) argemonis Cockerell, 1896 | Prickly-poppy Andrena |
| Andrena (Plastandrena) crataegi Robertson, 1893 | Hawthorn Andrena |
| Andrena (Plastandrena) mellea Cresson, 1868 | |
| Andrena (Plastandrena) prunorum Cockerell, 1896 | |
| Andrena (Thysandrena) medionitens Cockerell, 1902 | |
| Andrena (Thysandrena) w-scripta Viereck, 1904 | W-Marked Miner Bee |
| Andrena (Trachandrena) miranda Smith, 1879 | Bunchberry dogwood |
| Andrena (Trachandrena) striatifrons Cockerell, 1897 | |
| Andrena calvata LaBerge, 1967 | |
| Andrena cercocarpi Cockerell, 1936 | |
| Andrena ofella LaBerge, 1967 | |
| Andrena simulata (Smith, 1879) | ⇒ Andrena canadensis Dalla Torre, 1896 |
| Anthidiellum (Loyolanthidium) ehrhorni Cockerell, 1900 | |
| Anthidium (Anthidium) atripes Cresson, 1879 | |
| Anthidium (Anthidium) edwardsii Cresson, 1878 | Edwards´ Wool-carder Bee |
| Anthidium (Anthidium) maculosum Cresson, 1878 | |
| Anthidium (Anthidium) utahense Swenk, 1914 | Utah Wool-carder Bee |
| Anthophora (Anthophoroides) californica Cresson, 1869 | California Anthophora |
| Anthophora (Clisodon) furcata Panzer, 1798 | Fork Tailed Flower Bee |
| Anthophora (Heliophila) curta (Provancher, 1895) | ⇒ Anthophora squammulosa Dours, 1869 |
| Anthophora (Lophanthophora) affabilis Cresson, 1878 | |
| Anthophora (Lophanthophora) coptognatha Timberlake, 1951 | |
| Anthophora (Lophanthophora) pacifica Cresson, 1878 | |
| Anthophora (Lophanthophora) porterae Cockerell, 1900 | |
| Anthophora (Lophanthophora) ursina Cresson, 1869 | |
| Anthophora (Melea) bomboides Kirby, 1837 | Bumble-bee-mimic Anthophora |
| Anthophora (Melea) occidentalis Cresson, 1869 | Digger bee |
| Anthophora (Mystacanthophora) montana Cresson, 1869 | Rocky Mountain Anthophora |
| Anthophora (Mystacanthophora) urbana Cresson, 1878 | |
| Anthophora (Paramegilla) centriformis Cresson, 1879 | |
| Apis (Apis) mellifera Linnaeus, 1758 | Drone-Bee |
| Ashmeadiella meliloti Cockerell, 1897 | |
| Bembix americana Fabricius, 1793 | American Sand Wasp |
| Bicyrtes ventralis Say, 1824 | |
| Bombus (Bombus) nevadensis Cresson, 1874 | Nevada bumble bee |
| Bombus (Bombus) occidentalis (Greene, 1858) | ⇒ Bombus terricola Kirby, 1837 |
| Bombus (Bombus) terricola Kirby, 1837 | Yellow-banded Bumble Bee |
| Bombus (Cullumanobombus) rufocinctus Cresson, 1863 | Red-belted Bumble Bee |
| Bombus (Fervidobombus) fervidus Fabricius, 1798 | Golden Northern Bumble Bee |
| Bombus (Fervidobombus) pensylvanicus De Geer, 1773 | American bumble bee |
| Bombus (Psithyrus) insularis (Smith, 1861) | ⇒ Bombus hypnorum Linnaeus, 1758 |
| Bombus (Pyrobombus) bifarius Cresson, 1878 | Black-notched Bumble Bee |
| Bombus (Pyrobombus) centralis Cresson, 1864 | Central bumble bee |
| Bombus (Pyrobombus) flavifrons Cresson, 1863 | Yellow head bumble bee |
| Bombus (Pyrobombus) huntii Greene, 1860 | Hunt bumble bee |
| Bombus (Pyrobombus) melanopygus Nylander, 1848 | Black tail bumble bee |
| Bombus (Pyrobombus) mixtus Cresson, 1878 | Fuzzy-horned bumble bee |
| Bombus (Pyrobombus) vosnesenskii Radoszkowski, 1862 | Vosnesensky bumble bee |
| Bombus (Separatobombus) morrisoni (Cresson, 1878) | ⇒ Bombus morrisoni Cresson, 1878 |
| Bombus (Subterraneobombus) borealis Kirby, 1837 | Northern amber bumble bee |
| Calliopsis (Calliopsima) chlorops Cockerell, 1899 | |
| Calliopsis (Hypomacrotera) subalpina Cockerell, 1894 | |
| Centris (Paracentris) caesalpiniae Cockerell, 1897 | |
| Centris (Wagenknechtia) cineraria Smith, 1854 | |
| Ceratina (Zadontomerus) nanula Cockerell, 1897 | Dwarf Ceratina |
| Ceratina (Zadontomerus) sequoiae Michener, 1936 | |
| Cerceris californica Cresson, 1865 | Winged surfclam |
| Cerceris crotonella Viereck & Co..., 1904 | |
| Cerceris finitima (Cresson, 1865) | ⇒ Cerceris arelate Banks, 1912 |
| Cerceris sexta Say, 1837 | Vegetable hummingbird |
| Coelioxys (Boreocoelioxys) banksi Crawford, 1914 | |
| Coelioxys (Boreocoelioxys) octodentata Say, 1824 | Eight-toothed Cuckoo-leaf-cutter |
| Coelioxys novomexicana Cockerell, 1909 | |
| Colletes bryanti Timberlake, 1951 | Bryant´s Cellophane Bee |
| Colletes eulophi Robertson, 1891 | |
| Colletes kincaidii Cockerell, 1898 | |
| Colletes lineatus Metz, 1910 | |
| Colletes phaceliae Cockerell, 1906 | Phacelia Cellophane Bee |
| Colletes sphaeralceae Timberlake, 1951 | |
| Diadasia (Coquillettapis) diminuta Cresson, 1878 | |
| Diadasia (Coquillettapis) sphaeralcearum Cockerell, 1905 | |
| Diadasia (Dasiapis) ochracea Cockerell, 1903 | Ochraceous Chimney Bee |
| Dianthidium (Dianthidium) concinnum Cresson, 1872 | |
| Dianthidium (Dianthidium) cressonii Dalla Torre, 1896 | |
| Dianthidium (Dianthidium) heterulkei Schwarz, 1940 | |
| Dianthidium (Dianthidium) pudicum Cresson, 1879 | |
| Dianthidium (Dianthidium) ulkei Cresson, 1878 | |
| Dianthidium platyurum Cockerell, 1923 | |
| Dieunomia (Epinomia) nevadensis Cresson, 1874 | Nevada Nomia |
| Ectemnius (Hypocrabro) continuus Fabricius, 1804 | Common Ectemnius |
| Elaphropoda bembidion Lieftinck, 1966 | Cascade cave amphipod |
| Eucerceris montana Cresson, 1882 | |
| Eucerceris tricolor Cockerell, 1897 | |
| Exomalopsis (Stilbomalopsis) solidaginis Cockerell, 1898 | |
| Habropoda morrisoni Cresson, 1878 | |
| Halictus (Monilapis) confusus Smith, 1853 | Confusing Furrow Bee |
| Halictus (Odontalictus) ligatus Say, 1837 | Ligated Furrow Bee |
| Halictus (Seladonia) tripartitus Cockerell, 1895 | |
| Heriades (Neotrypetes) carinatus Cresson, 1864 | |
| Hoplisoides nebulosus Packard, 1867 | |
| Hoplitis (Cyrtosmia) hypocrita Cockerell, 1906 | |
| Hoplitis (Proteriades) palmarum Cockerell, 1935 | |
| Hylaeus (Hylaeus) annulatus Linnaeus, 1758 | Annulate Masked Bee |
| Larropsis (Larropsis) tenuicornis Smith, 1856 | |
| Lasioglossum (Dialictus) aquilae Cockerell, 1898 | |
| Lasioglossum (Dialictus) pruinosum Robertson, 1892 | Hoary Sweat Bee |
| Lasioglossum (Lasioglossum) sisymbrii Cockerell, 1895 | |
| Lasioglossum (Lasioglossum) trizonatum Cresson, 1874 | |
| Lasioglossum callophrys Ebmer, 2002 | |
| Macrotera (Macroteropsis) haplura Cockerell, 1922 | |
| Megachile (Argyropile) parallela Smith, 1853 | Parallel Leaf-cutter Bee |
| Megachile (Chelostomoides) angelarum Cockerell, 1902 | |
| Megachile (Litomegachile) brevis (Say, 1837) | ⇒ Megachile pseudobrevis Mitchell, 1934 |
| Megachile (Litomegachile) coquilletti Cockerell, 1915 | |
| Megachile (Litomegachile) gentilis Cresson, 1872 | Leafcutter bee |
| Megachile (Litomegachile) lippiae Cockerell, 1900 | |
| Megachile (Litomegachile) snowi (Mitchell, 1927) | ⇒ Megachile mendica Cresson, 1878 |
| Megachile (Megachile) montivaga Cresson, 1878 | Silver-tailed Petal-cutter Bee |
| Megachile (Pseudocentron) sidalceae Cockerell, 1897 | |
| Megachile (Sayapis) fidelis Cresson, 1878 | Faithful leafcutting bee |
| Megachile (Sayapis) inimica Cresson, 1872 | Hostile Leaf-cutter Bee |
| Megachile (Sayapis) policaris Say, 1831 | |
| Megachile (Sayapis) pugnata Say, 1837 | Pugnacious Leaf-cutter Bee |
| Megachile (Xanthosarus) agustini Cockerell, 1905 | |
| Megachile (Xanthosarus) comata Cresson, 1872 | |
| Megachile (Xanthosarus) perihirta Cockerell, 1898 | Furry Leaf-cutter Bee |
| Megachile mellitarsis Cresson, 1878 | |
| Megachile mojavensis Mitchell, 1934 | |
| Melissodes (Eumelissodes) agilis Cresson, 1878 | Agile Long-horned Bee |
| Melissodes (Eumelissodes) confusa Cresson, 1878 | |
| Melissodes (Eumelissodes) coreopsis Robertson, 1905 | Subterranean clover |
| Melissodes (Eumelissodes) limbus LaBerge, 1961 | |
| Melissodes (Eumelissodes) tristis Cockerell, 1894 | |
| Melissodes (Heliomelissodes) rivalis Cresson, 1872 | |
| Melissodes (Melissodes) paroselae (Cockerell, 1905) | ⇒ Melissodes parosetae Cockerell, 1905 |
| Melissodes (Melissodes) tepaneca Cresson, 1878 | Tepanec Long-horned Bee |
| Melissodes (Melissodes) tepida Cresson, 1878 | |
| Melissodes (Tachymelissodes) sphaeralceae Cockerell, 1896 | |
| Melissodes sonorensis LaBerge, 1963 | |
| Neolarra verbesinae Cockerell, 1895 | |
| Nomada gutierreziae Cockerell, 1896 | |
| Nomada texana Cresson, 1872 | Texas Nomad Bee |
| Nomada vegana (Cockerell, 1903) | ⇒ Nomada modesta Cresson, 1863 |
| Nomada zebrata Cresson, 1878 | |
| Nysson intermedius Viereck, 1908 | |
| Osmia (Cephalosmia) montana Cresson, 1864 | |
| Osmia (Helicosmia) coloradensis Cresson, 1878 | Colorado Osmia |
| Osmia (Melanosmia) albolateralis Cockerell, 1906 | |
| Osmia (Melanosmia) cyanella Cockerell, 1897 | |
| Osmia (Melanosmia) simillima Smith, 1853 | Similar Mason Bee |
| Oxybelus uniglumis Linnaeus, 1758 | Common Spiny Digger Wasp |
| Paranthidium (Paranthidium) jugatorium Say, 1824 | Sunflower Burrowing-Resin Bee |
| Pemphredon (Cemonus) inornata Say, 1824 | Shuckard's Wasp |
| Pemphredon montana Dahlbom, 1845 | |
| Perdita (Cockeriella) coreopsidis Cockerell, 1906 | Tickseed Perdita |
| Perdita (Hexaperdita) ignota Cockerell, 1896 | |
| Perdita (Perdita) crotonis Cockerell, 1896 | |
| Perdita (Perdita) exclamans Cockerell, 1895 | |
| Perdita (Perdita) melanostoma Swenk & Cock..., 1907 | |
| Perdita (Perdita) punctosignata Cockerell, 1895 | |
| Perdita (Perdita) salicis Cockerell, 1896 | |
| Perdita (Perdita) similis Timberlake, 1958 | |
| Perdita (Perdita) stathamae Timberlake, 1964 | |
| Perdita (Perdita) triangulifera Timberlake, 1964 | |
| Perdita (Perdita) zebrata Cresson, 1878 | |
| Perdita sphaeralceae Cockerell, 1896 | |
| Philanthus multimaculatus Cameron, 1891 | |
| Philanthus ventilabris Fabricius, 1798 | Bee-killer wasp |
| Plenoculus propinquus Fox, 1894 | |
| Prionyx atratus Lepeletier d..., 1845 | |
| Protandrena mexicanorum Cockerell, 1896 | |
| Protoxaea gloriosa Fox, 1893 | Glorious Protoxaea |
| Pseudopanurgus (Pseudopanurgus) aethiops Cresson, 1872 | |
| Pseudopanurgus helianthi Mitchell, 1960 | |
| Sphex subtruncatus orius (van der Vecht, 1957) | ⇒ Sphex subtruncatus Dahlbom, 1843 |
| Stelis (Dolichostelis) rudbeckiarum Cockerell, 1904 | |
| Stelis (Stelidium) ashmeadiella | |
| Stelis (Stelis) carnifex Cockerell, 1911 | |
| Stelis (Stelis) montana Cresson, 1864 | |
| Steniolia duplicata Provancher, 1888 | Freckled milkvetch |
| Stizoides renicinctus Say, 1823 | |
| Svastra (Idiomelissodes) duplocincta Cockerell, 1905 | |
| Tachysphex ashmeadii Fox, 1894 | |
| Tachysphex occidentalis Pulawski, 1982 | |
| Tachytes pepticus (Say, 1837) | ⇒ Tachytes sayi Banks, 1942 |
| Tetraloniella (Tetraloniella) albata Cresson, 1872 | |
| Trachusa (Heteranthidium) larreae Cockerell, 1897 | |
| Trachusa (Heteranthidium) occidentalis Cresson, 1868 | |
| Trachusa (Heteranthidium) zebrata Cresson, 1872 | |
| Triepeolus bimorulus Rightmyer, 2008 | |
| Triepeolus verbesinae Cockerell, 1897 | |
| Xeromelecta (Melectomorpha) californica Cresson, 1878 | California Xeromelecta |
