Volume V: Bulletin of the United States Geological and Geographical Survey of the Territories, 1879

The object of the present paper is to set forth some interesting biological facts relating to the gall-making Pemphiginre, and which were presented in abstract at the late meeting of the American Association for the Advancement of Science. These facts have a special interest just at this time on account of the close relation·ship between the insects of the sub-family in question and the notorious Grape-vine Phylloxera (Phylloxera vastatrix).