Sunday, June 26, 2016

Sooty Hairstreaks vs. Boisduval's Blues

Sooty Hairstreaks (Satyrium fuliginosa & semiluna) and Boisduval’s Blues (Icaricia icarioides) share some of the same larval host plants and are easy to confuse with each other without a closer look. Female Boisduval’s Blues often have a light dusting of blue scales on the dorsal surface (1), and may have a dark gray bar in the DFW cell (2). Sooty Hairstreaks never have these two features and their ventral spots are almost always smaller and fuzzier than Boisduval’s Blues, especially between their VFWs (3). Marginal VHW spots are slightly chevron-shaped on Boisduval’s and round on Sooty (4), or may be missing on both species (5).


  1. Nice to meet you and your parents on Reecer Creek Road, Caitlin! And thanks for the location tips. These ID guides are helpful as I wade through my hundreds of photos. --John from Michigan

    1. Glad to be of help, you're partly why I posted this one. I'd like to see your checkerspot photos when you've sorted them out, you mentioned thinking you'd seen two species and I told you I've only ever seen E. colon there, but after consulting some other sources there is a possibility of E. editha and anicia, so I'm curious to see what you found.

  2. Thanks, Caitlin. I've posted most of my photos here and have provided an ID guess on most: Hoping for better weather next visit! I've skipped over some of the blues and all the frits for now. I think you were right about the checkerspots being E. colon. Once I get IDs settled I'll clear out some of the junk photos!