In other accounts it is stated that the larvæ live covered by masses of froth which the insects produce by expelling from their beak the juices drawn out of the tree.
The above extracts are sufficient to indicate the common belief among entomologists that the insect in some way emits this froth from the body. A most cursory examination of the creature, however, shows that its only secretion is a clear fluid.
Fig. 1.—Grass stalk and leaves, showing appearance of froth.
The so-called frog spittle or cuckoo spit ([Fig. 1]) appears as little flecks of froth on grass, buttercups, and many other plants during the early summer. These flecks of froth may be found very commonly at the junction of the leaf with the stem. Immersed in this froth is found a little green insect, sometimes two or three of them, concealed by the same moist covering. This little creature represents the early stage of an insect which in its full growth still lives upon grass, and is easily recognized by its triangular shape and its ability of jumping like a grasshopper. There are a number of species; the one living on grass apparently confines itself to the grass alone, though I have seen one species that frequents a number of different plants. A species found on the white pine is dark brown in color, and the froth in which it is found not only hangs pendent from the branch, but the lower portion appears as a large drop of clear water.
Fig. 2.—The insect first emitting a clear fluid which fills up the interspaces between its body and the stem of grass upon which it rests.
Fig. 3.—After the lapse of some time it begins rapidly to make bubbles.
