| Diachasmimorpha longicaudata Ashmead, 1905 | Long-tailed fruit-fly parasite |
| Doryctobracon anastrephilum Marsh, 1970 | |
| Doryctobracon areolatus Szépligeti, 1911 | Braconid wasp |
| Doryctobracon cereus (Gahan, 1919) | ⇒ Doryctobracon areolatus Szépligeti, 1911 |
| Euopius albipalpus Fischer, 1965 | |
| Euopius analis Fischer, 1965 | |
| Euopius cubitalis Fischer, 1965 | |
| Euopius macrops Fischer, 1965 | |
| Eurytenes abnormis Wesmael, 1835 | |
| Opius (Allophlebus) aridis Gahan, 1913 | Parasitoid wasp |
| Opius (Allophlebus) canimensis Fischer, 1965 | |
| Opius (Allophlebus) dizygomyzae Fischer, 1965 | |
| Opius (Allophlebus) eastridgeanus Fischer, 1965 | |
| Opius (Allophlebus) longicubitalis Fischer, 1965 | |
| Opius (Allophlebus) mediopectus Fischer, 1965 | |
| Opius (Allophlebus) nomininguensis Fischer, 1965 | |
| Opius (Allophlebus) petiolaris Fischer, 1965 | |
| Opius (Allophlebus) pickensanus Fischer, 1965 | |
| Opius (Allophlebus) rheasilviae Fischer, 1970 | |
| Opius (Allotypus) irregularis Wesmael, 1835 | Cooper wolfberry |
| Opius (Apodesmia) ithacensis Fischer, 1964 | |
| Opius (Apodesmia) karesuandensis Fischer, 1964 | |
| Opius (Apodesmia) middlekauffi Fischer, 1964 | |
| Opius (Apodesmia) polyzonius Wesmael, 1835 | Cooper wolfberry |
| Opius (Apodesmia) tablerockensis Fischer, 1964 | |
| Opius (Baeocentrum) coleogaster Fischer, 1964 | |
| Opius (Baeocentrum) foutsi Fischer, 1964 | |
| Opius (Baeocentrum) gainesvillensis Fischer, 1964 | |
| Opius (Baeocentrum) myakkensis Fischer, 1964 | |
| Opius (Baeocentrum) punctipes Fischer, 1964 | |
| Opius (Baeocentrum) restrictus Fischer, 1964 | |
| Opius (Baeocentrum) resupinus Fischer, 1964 | |
| Opius (Baeocentrum) smithi Fischer, 1964 | |
| Opius (Cryptonastes) brunescens Fischer, 1964 | |
| Opius (Cryptonastes) nigritellae Fischer, 1964 | |
| Opius (Cryptonastes) sierraanchaensis Fischer, 1964 | |
| Opius (Gastrosema) adductus Fischer, 1964 | |
| Opius (Gastrosema) castaneigaster Fischer, 1964 | |
| Opius (Gastrosema) clevelandensis Fischer, 1964 | |
| Opius (Gastrosema) deiphobe Fischer, 1970 | |
| Opius (Gastrosema) flaviceps Gahan, 1915 | |
| Opius (Gastrosema) intermissus Fischer, 1964 | |
| Opius (Gastrosema) niobe Fischer, 1970 | |
| Opius (Gastrosema) oscinidis Ashmead, 1889 | |
| Opius (Gastrosema) pallas Fischer, 1970 | |
| Opius (Gastrosema) porteri Fischer, 1964 | |
| Opius (Gastrosema) relativus Fischer, 1964 | |
| Opius (Gastrosema) salmonensis Fischer, 1964 | |
| Opius (Gastrosema) striativentris Gahan, 1915 | Robust Schreber's dicranella moss |
| Opius (Gastrosema) tangens Fischer, 1964 | |
| Opius (Gastrosema) walleyi Fischer, 1964 | |
| Opius (Gastrosema) weemsi Fischer, 1964 | |
| Opius (Hypocynodus) cochisensis Fischer, 1965 | |
| Opius (Hypocynodus) crassiceps Gahan, 1915 | Robust Schreber's dicranella moss |
| Opius (Hypocynodus) oralis Fischer, 1965 | |
| Opius (Ilicopius) pulchriceps Szépligeti, 1898 | Braconid wasp |
| Opius (Merotrachys) antennatus Fischer, 1965 | |
| Opius (Merotrachys) antrimensis Fischer, 1965 | |
| Opius (Merotrachys) bromensis Fischer, 1965 | |
| Opius (Merotrachys) brooki Fischer, 1965 | |
| Opius (Merotrachys) brownsvillensis Fischer, 1965 | |
| Opius (Merotrachys) diastatae Ashmead, 1889 | |
| Opius (Merotrachys) hubbelli Fischer, 1965 | |
| Opius (Merotrachys) lansingensis Fischer, 1965 | |
| Opius (Merotrachys) martini Fischer, 1965 | |
| Opius (Merotrachys) pandora Fischer, 1970 | |
| Opius (Merotrachys) paulior Fischer, 1965 | |
| Opius (Merotrachys) paulus Fischer, 1965 | |
| Opius (Merotrachys) peleus Fischer, 1970 | |
| Opius (Merotrachys) richardsi Fischer, 1965 | |
| Opius (Merotrachys) telamonis Fischer, 1970 | |
| Opius (Merotrachys) telramundi Fischer, 1970 | |
| Opius (Merotrachys) virentis Fischer, 1965 | |
| Opius (Misophthora) hollisterensis Fischer, 1964 | |
| Opius (Misophthora) jacobi Fischer, 1964 | |
| Opius (Misophthora) perminutus Fischer, 1964 | |
| Opius (Misophthora) pilosus Fischer, 1964 | |
| Opius (Nosopaeopius) angustistriatus Fischer, 1964 | |
| Opius (Nosopaeopius) aureliae Fischer, 1957 | |
| Opius (Nosopaeopius) baldufi Muesebeck, 1950 | California pinefoot |
| Opius (Nosopaeopius) bidentis Fischer, 1964 | |
| Opius (Nosopaeopius) downesi Gahan, 1919 | |
| Opius (Nosopaeopius) krombeini Fischer, 1964 | |
| Opius (Nosopaeopius) leevingensis Fischer, 1964 | |
| Opius (Nosopaeopius) rainierensis Fischer, 1964 | |
| Opius (Nosopoea) chapmani Fischer, 1964 | |
| Opius (Nosopoea) crandalli Fischer, 1964 | |
| Opius (Nosopoea) curtiarticulatus Fischer, 1964 | |
| Opius (Nosopoea) kinleyensis Fischer, 1964 | |
| Opius (Nosopoea) lemonensis Fischer, 1964 | |
| Opius (Nosopoea) pisgahensis Fischer, 1964 | |
| Opius (Nosopoea) troyensis Fischer, 1964 | |
| Opius (Opiognathus) carinus Fischer, 1964 | |
| Opius (Opiognathus) cinctus Provancher, 1886 | Lemmon's milkvetch |
| Opius (Opiognathus) demosthenis Fischer, 1970 | |
| Opius (Opiognathus) hartleyi Fischer, 1964 | |
| Opius (Opiognathus) liriomyzae Fischer, 1964 | |
| Opius (Opiognathus) rufipleurum Fischer, 1964 | |
| Opius (Opiognathus) similarius Fischer, 1964 | |
| Opius (Opiognathus) succineus Gahan, 1913 | Schreber's dicranella moss |
| Opius (Opiostomus) hardmanni Fischer, 1964 | |
| Opius (Opiostomus) mandibularis Gahan, 1915 | Robust Schreber's dicranella moss |
| Opius (Opiostomus) utahensis Gahan, 1913 | Schreber's dicranella moss |
| Opius (Opiothorax) bruneipes Gahan, 1913 | Schreber's dicranella moss |
| Opius (Opiothorax) chewaucanus Fischer, 1965 | |
| Opius (Opiothorax) curticubitalis Fischer, 1965 | |
| Opius (Opiothorax) douglasanus Fischer, 1965 | |
| Opius (Opiothorax) dubitarius Fischer, 1965 | |
| Opius (Opiothorax) gahani Samiuddin & ..., 2009 | Ghost Pipe |
| Opius (Opiothorax) interjectus Fischer, 1965 | |
| Opius (Opiothorax) wattacooanus Fischer, 1965 | |
| Opius (Pendopius) crescentensis Fischer, 1965 | |
| Opius (Pendopius) gerdi Papp, 1982 | |
| Opius (Pendopius) pendulus Haliday, 1837 | |
| Opius (Pendopius) pseudoromensis Fischer, 1965 | |
| Opius (Pendopius) romensis Fischer, 1965 | |
| Opius (Pendopius) romensoides Fischer, 1965 | |
| Opius (Pleurosema) euwattacooanus Fischer, 1964 | |
| Opius (Pleurosema) globiformis Fischer, 1964 | |
| Opius (Pleurosema) latitemporalis Fischer, 1964 | |
| Opius (Pleurosema) otiosus Gahan, 1917 | |
| Opius (Pleurosema) parawattacooanus Fischer, 1964 | |
| Opius (Pleurosema) pechumani Fischer, 1970 | |
| Opius (Pleurosema) pilosinotum Fischer, 1964 | |
| Opius (Pleurosema) sybille Fischer, 1970 | |
| Opius (Pleurosema) thalis Fischer, 1970 | |
| Opius (Rhogadopsis) aberrans Viereck, 1905 | Twining screwstem |
| Opius (Rhogadopsis) basicastaneus Fischer, 1964 | |
| Opius (Rhogadopsis) clellanvillensis Fischer, 1964 | |
| Opius (Rhogadopsis) dimidiatus Ashmead, 1889 | Parasitoid wasp |
| Opius (Rhogadopsis) northcarolinensis Fischer, 1964 | |
| Opius (Rhogadopsis) ordinarius Fischer, 1964 | |
| Opius (Rhogadopsis) ornatigaster Fischer, 1964 | |
| Opius (Rhogadopsis) pallidipalpalis Fischer, 1964 | |
| Opius (Rhogadopsis) paradisiacus Fischer, 1964 | |
| Opius (Rhogadopsis) paralleliformis Fischer, 1964 | |
| Opius (Rhogadopsis) pauper Fischer, 1964 | |
| Opius (Rhogadopsis) ruficolor Fischer, 1964 | |
| Opius (Rhogadopsis) stenopectus Fischer, 1964 | |
| Opius (Stomosema) apicalis Gahan, 1915 | Robust Schreber's dicranella moss |
| Opius (Stomosema) rufocinctus Gahan, 1915 | Robust Schreber's dicranella moss |
| Opius (Thoracosema) cannonbeachensis Fischer, 1970 | |
| Opius (Thoracosema) columbiacus Fischer, 1964 | |
| Opius (Thoracosema) convergitalis Fischer, 1964 | |
| Opius (Thoracosema) farmingdalicus Fischer, 1964 | |
| Opius (Thoracosema) igneus Fischer, 1964 | |
| Opius (Thoracosema) isolatae Fischer, 1964 | |
| Opius (Thoracosema) parkeranus Fischer, 1964 | |
| Opius (Thoracosema) parkercreekensis Fischer, 1964 | |
| Opius (Thoracosema) perpygmaeus Fischer, 1964 | |
| Opius (Thoracosema) prolongatus Fischer, 1964 | |
| Opius (Thoracosema) pseudocolumbiacus Fischer, 1964 | |
| Opius (Thoracosema) southcarolinensis Fischer, 1964 | |
| Opius (Thoracosema) tibialis Ashmead, 1893 | |
| Opius (Tolbia) alachuanus Fischer, 1964 | |
| Opius (Tolbia) caesus Haliday, 1837 | |
| Opius (Tolbia) confundens Fischer, 1964 | |
| Opius (Tolbia) coriaceus Gahan, 1917 | |
| Opius (Tolbia) dreisbachi Fischer, 1964 | |
| Opius (Tolbia) globigaster Fischer, 1964 | |
| Opius (Tolbia) hancockanus Fischer, 1964 | |
| Opius (Tolbia) heroicus Fischer, 1970 | |
| Opius (Tolbia) hoffmanni Fischer, 1964 | |
| Opius (Tolbia) rudiformis Fischer, 1958 | |
| Opius (Tolbia) sabroskyi Fischer, 1964 | |
| Opius aciurae Fischer, 1964 | |
| Opius additivus Fischer, 1965 | |
| Opius alconanus Fischer, 1964 | |
| Opius americanus Gahan, 1915 | Robust Schreber's dicranella moss |
| Opius ampla Ashmead, 1890 | |
| Opius anaximandri Fischer, 1970 | |
| Opius anaximensis Fischer, 1970 | |
| Opius aquaticus (Muesebeck, 1933) | ⇒ Opius caesus Haliday, 1837 |
| Opius atrocoxalis Ashmead, 1890 | |
| Opius basiniger Viereck, 1905 | |
| Opius bigdeltanus Fischer, 1965 | |
| Opius blantoni Fischer, 1964 | |
| Opius brunneitarsis Gahan, 1915 | Robust Schreber's dicranella moss |
| Opius canaliculatus Gaham, 1915 | |
| Opius cincticornis Gahan, 1915 | Robust Schreber's dicranella moss |
| Opius coloradensis Gahan, 1915 | Robust Schreber's dicranella moss |
| Opius comatus Wesmael, 1835 | Cooper wolfberry |
| Opius complicans Fischer, 1965 | |
| Opius differentiarius Fischer, 1965 | |
| Opius dimensis Fischer, 1964 | |
| Opius ehrhorni Gahan, 1915 | Robust Schreber's dicranella moss |
| Opius empedoplis Fischer, 1970 | |
| Opius frequens Fischer, 1964 | |
| Opius fulvicollis Thomson, 1895 | Bull filaree |
| Opius glasgowi Fischer, 1964 | |
| Opius gracillariae (Gahan, 1915) | ⇒ Opius striativentris Gahan, 1915 |
| Opius gravicornis Fischer, 1964 | |
| Opius ignifer Fischer, 1964 | |
| Opius ilicis (Nixon, 1939) | ⇒ Opius pulchriceps Szépligeti, 1898 |
| Opius juniperi Fischer, 1964 | |
| Opius labradorensis Fischer, 1965 | |
| Opius lectoides Gahan, 1930 | |
| Opius lectus Gahan, 1919 | |
| Opius lemnaphilae Muesebeck, 1939 | Florida pygmy pipes |
| Opius luteiceps Viereck, 1905 | Twining screwstem |
| Opius macrocerus Thomsom, 1895 | Bull filaree |
| Opius malivorellae Fischer, 1964 | |
| Opius microsomaticus Fischer, 1965 | |
| Opius montana Ashmead, 1890 | |
| Opius nanus Provancher, 1888 | Freckled milkvetch |
| Opius nigrocastaneus Viereck, 1905 | |
| Opius nitidulator Nees, 1834 | |
| Opius notaulicus Fischer, 1964 | |
| Opius ornatus Fischer, 1964 | |
| Opius pallipes (Wesmael, 1835) | ⇒ Xenarcha mellipes Provancher, 1880 |
| Opius parvifossa Fischer, 1964 | |
| Opius parvulus Wesmael, 1835 | |
| Opius pequodorum Viereck, 1917 | Yellow screwstem |
| Opius phoenicensis Fischer, 1965 | |
| Opius piceus Thomson, 1895 | Bull filaree |
| Opius provancheri Dalla Torre, 1886 | |
| Opius richmondi Gahan, 1919 | |
| Opius robsonensis Fischer, 1964 | |
| Opius rosicola Muesebeck, 1950 | California pinefoot |
| Opius rudis Wesmael, 1835 | Cooper wolfberry |
| Opius schuleri Fischer, 1964 | |
| Opius severini Fischer, 1964 | |
| Opius suturalis Hgahan, 1913 | Higgin's barberry |
| Opius tabellariae Fischer, 1964 | |
| Opius takomaanus Fischer, 1965 | |
| Opius townesi Fischer, 1965 | |
| Opius turneri Gahan, 1919 | |
| Opius westerlyanus (Fischer, 1964) | ⇒ Opius foutsi Fischer, 1964 |
| Trigonospilus hopkinsi Ashmead, 1900 | |
