Oak Wheat Gall 
Oblong Woolcarder Bee 
Odontomachus erythrocephalus 
Odontomachus hastatus 
Odontomachus troglodytes 
Odontoponera denticulata 
Odorous House Ant 
Okinawa Mud Wasp 
Omicroides singularis 
Ophelimus maskeli 
Ophion idoneus 
Ophion luteus 
Ophion obscuratus 
Ophion scutellaris 
Orange Head Scolid Wasp 
Orange-belted Bumble Bee 
Orange-collared Spider Wasp 
Orange-legged Furrow Bee 
Orchard mason bee 
Oreumenes decoratus 
Organ-pipe mud dauber 
Oriental hornet 
Ornate-tailed Digger Wasp 
Osmia aurulenta