In the Canadian Entolnologist for November, 1925, I reviewed tne Canadian species of Lydella Desv. As certain changes in the terminology therein proposed are necessary it seems advisable to review the related forms and present a key to the genera concerned. The species under discussion, with some exceptions, trace to Masicera Macq. in keys dealing with the Nearctic fauna and the key to the genera may be used to supplement those in Williston's Manual, 1908, and Coquillett's “Revision.”