The April number of the Entomologist contains a commnunication from my esteemed friend Mr. S. H. Scudder, with reference to the yellow male variety of this species. In it he asks several questions which I shall endeavour to answer, adding some other particulars to make my notes as complete as possible.

I think that entomologists will agree with me in considering P. rapæas one of the most interesting insects existing on this continent, not only with refercnce to its destructive habits, but also on account of its recent introduction and rapid dissemination over the country.