O
Odynerus (see also the varieties below), [28]–59, [150], [176]
Odynerus alpestris (see [Alpine Odynerus])
Odynerus nidulator (see [Nest-building Odynerus])
Odynerus Reaumurii, [35]
Odynerus reniformis, [35]–59, [177]–178, [201]–205
Odynerus spinipes, [35]
Osmia (see also [three-horned Osmia]), [31]–32, [69], [150], [168]–169, [182], [186]
Owl (see also [Screech-owl]), [288]