1958
DUELLMAN: LEPTODEIRA
121
body horizontally from a branch for approximately half of the total length of the snake. Leptodeira frenata frenata, frenata malleisi, and septentrionalis polysticta are semi-arboreal in their habits as indicated by their presence in epiphytic plants. Observations on polysticta and frenata show that these snakes
are capable of more rapid movement in bushes and trees than are the heavier-bodied
FOOD AND Snakes of the genus Leptodeira feed on small lizards and anurans, the latter apparently making up the bulk of the diet. Lizards were most commonly found in the stomachs of specimens collected during the dry season, a time when many frogs and toads are not active. Observations made on L. annulata cussiliris, maculata, punctata, and septentrionalis polysticta in Mexico show that these snakes are frequently encountered at breeding congregations of frogs during the breeding season. Three L. a. cussiliris were found at a small pond near Zanatepec, Oaxaca, where there was a large breeding congregation of Hyla robertmertensi. Leptodeira maculata was found in abundance in flooded fields near Apatzingan, Michoacan, where Hyla smithi was breeding. A juvenile L. a. polysticta was found grasping a metamorphosing Hyla staufferi. Smith (1943) reported L. s. polysticta feeding on the eggs of Agalychnis moreleti at Finca Juarez, Chiapas. The eggs of Agalychnis are suspended from leaves or branches of bushes that overhang ponds or streams. Richard Etheridge and I observed polysticta feeding on the eggs of Agalychnis callidryas near Catemaco, Veracruz. The snake was found in a bush at the edge of a pond; the distended mouth with the gelatin dripping from its jaws presented a weird sight. Eggs, presumably those of Agalychnis dacnicolor, were found in the stomach of a Leptodeira s. bressoni collected at Coalcom6n, Michoac.n. I know of no other snakes that feed on frog eggs. The food items found in the stomachs of preserved specimens are listed in table 30.
FEEDING Further items reported in the literature include Ctenosaura similis similis in L. f. yucatanensis (Barbour and Cole, 1906) and Pternohyla fodiens in L. s. polysticta (Firschein, 1951). Captive specimens feed on small frogs and lizards. Ditmars (1945) reported that captive L. s. septentrionalis ate mice. This is, so far as I know, the only report of Leptodeira feeding on warm-blooded prey. Observations were made on feeding habits of captive L. f. frenata, maculata, punctata, s. ornata, and s. polysticta. All these were fed frogs. When small frogs were placed in the cage the snakes would grab hold of one, usually quickly work to the head, and swallow the frog in much the same manner utilized by Thamnophis or Natrix. Sometimes the frog was still alive during the swallowing process, which indicates that with small prey the snake may not engage the enlarged, grooved fangs and inject venom. With larger frogs the snake strikes, grabs hold, and rapidly chews, opening its mouth widely until the enlarged, grooved fangs are engaged. Then it holds the prey until movement stops. The lenigth of time necessary for the venom to take effect varies with the size of the snake and that of the frog; however, on the basis of my limited observations two to five minutes seem to suffice for most frogs. Data on the effect of the venom on large frogs and lizards are lacking. In view of the fact that the venom of several species of opisthoglyph colubrids is of sufficient potency to result in the death of human beings, investigations of the properties of these venoms is of considerable importance.
terrestrial forms. All species of Leptodeira are nocturnal. Although, according to Walls (1942), the eye is well adapted for diurnal sight, I know of no specimens found abroad during the day.