Until 2009, this species was not recognized in BC. However, Schmidt (2009) showed that all specimens previously thought to be
Hemaris diffinis, were actually
H. thetis. Inhis paper, he says:
"Western North American populations previously treated as Hemaris diffinis (Boisduval) are shown to be a distinct species, Hemaris thetis Boisduval), based on differences in habitus, genitalic morphology, mtDNA sequence variation and larval phenotype. Both species occur in strict sympatry at several localities in western Alberta without evidence of intergradation. Hemaris senta is a colour variant of
H. thetis, and synonomized under the latter."
Avis (2014, pers. comm.) says: "You would only expect to find H. thetis in BC other than possibly in the Peace River."
Reference:
Schmidt, B. Christian (2009). Hemaris thetis (Boisduval, 1855) (Sphingidae) is a Distinct Species. Journal of the Lepidopterists Society 63(2), 2009, 100-109.