SeasonalityAdults emerge in July (Strickland 1953).
IdentificationA mid- to large-sized Okanagana with a wingspan of about 60mm. Predominantly shiny black with orange segment borders and markings. O. rimosa is similar and sympatric to occidentalis in the western parts of the province, but occidentalis has a broader forewing (width:length ratio of 0.34 - 0.36, 0.29 - 0.31 in rimosa), and is shiny black rather than the dull black of rimosa. Compared to bella, occidentalis has a dense covering of long hairs on the underside of the abdomen, bella has only sparse, short hairs. The ventral plate of the terminal abdominal segment is doubly notched in female occidentalis, singly in bella (Davis 1919).