Larva morphology [Y.Alarie, A.Short, M.Garcia, L.Joly]:
http://waterbeetles.kubiodiversityinstitute.org/ShortPDFs/Alarieetal2011.pdf
Meruidae [R.Beutel, M.Balke, W.Steiner]:
http://entomology.si.edu/StaffPages/Steiner/2006_Beutel-et-al_Cladistics.pdf