Scott, James A., authorJames A. Scott, publisher2007-01-032007-01-031982-11-15http://hdl.handle.net/10217/84910Nov. 15, 1982.Includes bibliographical references (pages 10-11).The egg, larva, and pupa of B. improba acrocnema are described and illustrated. The larval foodplant is Salix nivalis. There are five instars; overwintering occurs in the fourth instar, and perhaps also in the first instar. Adults fly slowly near the ground, and are very local. Males patrol to find females. Adults often visit flowers, and bask on dark soil by spreading the wings laterally. A binomial method is derived and used to determine daily population size. Daily population size may be as large as 655, and yearly population size may reach two thousand in a few hectares.born digitaljournals (periodicals)engCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.ButterfliesLepidopteraText