Common Tree Frog

Hyla versicolor Le Conte

Colour.—Varying through many shades of green, brown, or grey. An oblique dark band on the top of the head, above each eye; a large dusky patch on the upper back, often star-shaped. The arms and legs are transversely barred. All of the dark markings may be indistinct or lacking. (See Plate XX, also Frontispiece.) A light spot below the posterior half of eye. Underparts light, bright orange-yellow posteriorly. Concealed leg surfaces vermiculated with brown.

Measurements.—Length 2 inches. Head short and broad; body stout. Ear two-thirds size of eye. The leg to the heel measures the length of the body forward to the eye.

Structure.—Skin covered with relatively coarse tubercles. Undersurfaces granulated, less conspicuously on the throat. Prominent fold of skin across breast. The disks on fingers and toes are large. Web of hind foot well-developed. Fingers slightly webbed. (See Figs. 134 to 142.)

Range.—Throughout eastern North America west to Kansas, northward into Canada, and southward into Texas.

Colour.—Sand-colour, light or dark grey, or olive. Three or four irregular rows of rounded dark spots on the back, or fewer large blotches. For colouration, see Colour Plate X. A curved band of dark colour between the eyes; this band may be broken in the midline, as it is in Hyla versicolor. Two or three bands of dark colour on the leg. (Fig. 144.) Eyes metallic yellow, or grey. Ear bronze. Many minute yellow spots on and between the large dark spots. (Fig. 144.) A white spot under the eye. Orange-yellow at the arm insertion, and on those parts of the femur and tibia that fold against each other. This orange is not spotted or marbled with dark. Underparts light. (Fig. 145.)

Measurements.—Length 1 1/2 inches to 2 inches. Head short. Leg to heel measure as long as that of the body forward to the anterior border of the eye. Tibia longer than femur.

Structure.—Skin rough, with small tubercles. (Fig. 143.) Head broad, flat, rounded in front. (Fig. 144.) Throat and underparts granular. (Fig. 145.) Nostrils terminal. Eyes small. Ear two-thirds the diameter of the eye. (Fig. 143.) A fold across the breast and another at the base of the throat. Disk on fingers and toes well developed. No webs between fingers. Web of foot medium in size; two joints of fourth toe free. Inner and outer tubercles present, small (Fig. 146): a prominent tarsal fold.

Range.—Hyla arenicolor is a Mexican form, found also across the border in the United States. It is reported from southern California, New Mexico, Utah, and Arizona.(Tucson, White River Canon, Arizona; Santa Fe, Fort Wingate, New Mexico; Upper Colorado River.)

Probably more familiar than any other member of the batrachian group, if we except the common toad, is this entertaining little acrobat of the frog world. (Figs. 134 to 137.) Some June morning when we are admiring the blue flowers of the clematis that climbs the porch, we see what looks like a yellowish white oval of putty plastered against the white pillar shaded by the vine. It is our Common Tree Frog (or Tree Toad, as it is called) sound asleep.

Late some July afternoon we sit reading by the porch window. Something seems to fly from the vines to the window. With sprawling legs, our tree frog climbs the smooth glass, to snuggle in the corner of a window-pane, his toes tucked well under him and pressed closely against the glass. The moist under surface of his body seems also to do its share of the work of holding him securely in this upright position. Now he awakes and wildly dashes for a fly, but only bangs his nose, because the fly is on the other side of the glass. If we catch the fly and carry it out to him, he takes it from our fingers into his cavernous pink mouth.

In August, we look for ripening grapes on the vine that covers the low stone smoke-house. On the mossy ledge of the roof, in the shade of a leaf, is a clump of grey lichen that comes to life when touched. Again it is our tree frog. He takes a flying leap, catches a slender stem by one sticky front foot and hangs swinging in air with outstretched legs. We are certain he will fall. Instead, he deliberately draws himself up to the swaying support and from it makes a second spring to a place of concealment.

We stand at the old-fashioned gate, and on the top of one of the white-painted posts there is something that looks like a flattened mass of smooth green wax. Even on looking closely, it is hard to distinguish the folds of the legs, so successfully are the adjoining skin surfaces blended. It is our sleepy tree frog, who may be slow to awake until we take him into our hands. Even then he clings confidingly to our finger, perfectly willing to remain on so comfortable a perch. In fact, it is not easy to get rid of his cool sticky toes. If we reverse the position of our finger so that his head is down, he turns clumsily until his head is upper-most again. His bright eyes, his confiding way, all his diminutive self, make a genuine appeal to our liking.