This is another lycaenid whose taxonomic status is subject to frequent change. An extreme lumper would include it in one huge species of Holarctic distribution, Celastrina argiolus, known in Britain as the Holly Blue, while a fine splitter would call our butterfly on Vancouver Island the Echo Blue or the Western Spring Azure C. echo. The middle-of-the-roader will be satisfied with Spring Azure C. ladon, with a distribution across most of North America. The pale greenish-white caterpillar is well hidden in the flower panicles of the shrub Holodiscus discolor known as Ocean Spray, although I have also found a deep claret variety equally well hidden in the flowers of Hardhack Spiraea douglasii. The pupa overwinters.