The larvae of all the American species of the Family Cercopidae as far as known envelope themselves in a frothy mass. Contrary to popular opinion and to most of the published accounts this froth does not issue as bubbles from the body of the insect, but is made by pushing the tip of the abdomen up out of the froth and grasping, with the anal appendages, a bubble of air and bringing it down and releasing it within a liquid film. This liquid film is simply the excretion from the alimentary canal of the sap which is imbibed by these insects in large quantities. This copious liquid excretion is a common occurrence in other families of the Homoptera. In the Plant Lice (Aphidae) it gathers in drops and is called “Honey Dew.” The Leaf Hoppers and Tree Hoppers expel a clear liquid with some force. In some species this is in sufficient amount so that when the insects are numerous the foliage may drip, producing the “Weeping trees” of the Southern States. This process of froth making in the Cercopidae was discovered and first correctly described by Professor E. S. Morse, of Salem, Mass., and published many years ago in his Elementary Zoology.[1] His observations were probably made on the larvae of _A. spumarius_ which belongs to the genus _Philaenus_ as now recognized. In the genus _Aphrophora_ as now limited little is known of the food habits of the larvae. One species (_A._ 4-_notata_) has been found on various plants and shrubs. The remaining three eastern species, which belong to a different group and are of some shade of brownish testaceous, have been given as feeding on pines in the adult state by various authors. Dr. Fitch has described the larvae of one of these (_A. parallela_, Fig. 4, Plate 10) as forming frothy masses on the tips of pine twigs, and in the Nat’l Museum Coll. are some _Aphrophora_ larvae labeled “Pa. On Pine, July 7,” that undoubtedly belong to this species leaving little room to doubt the correctness of Fitch’s determination. There are two species belonging to the _parallela_ group occurring in the Rocky Mountain region both found in the adult stage on pines. Of one of these (_A. permutata_, Fig. 1, 2 and 3, Plate 10) larvae were found in abundance on two different plants _Chrysopsis villosa_ and _Lupinus sp._ Both of these plants grow in clumps and it was always down in the bases of these clumps, some of them often down below the surface of the ground among the roots, that the larvae were found. Often ten or fifteen would be found in a single clump their united froth masses, held up by the coarse stems, reaching a diameter of two inches or more.