Bug I.D.

By an edhat subscriber

With the winter and spring rains, my mother ferns have been so happy and abundant, but recently I noticed some have been wasting away.  Looking closely I can see an infestation of little brown helmet-like bugs that appear to be the culprit.  Can anyone ID these guys and give me an idea of how I can control them?  My go-to bug spray, Monterey (spinosad) has been ineffective.  Thank you!