Hylidae 



The tadpoles hatch in from six to twelve days, depending on 

 the temperature. In less than a week after hatching, the gills are 

 covered and the usual "pollywog" form is assumed. In seven 

 or eight weeks from the time that the eggs are laid, the tadpoles l 

 are full-grown. They are small and delicate. Each measures 

 one inch long, including the tail, which is twice the length of head 

 and body together. The undersurface of the body is reddish 

 bronze, shining with metallic lustre. The characteristics of the 

 head of the adult frog can be seen in the tadpole even before the 

 front legs appear; that is, the eyes are set extremely wide apart, 

 the lines between the eyes and the nostrils are sharply angled, and 

 the upper jaw projects beyond the lower. The toes of the back legs 

 are provided with distinct pads before the front legs appear. The 

 cross on the back often shows before the tail begins to be absorbed. 



As soon as the front legs break through their coverings, the 

 creatures are eager to leave the water. They may be found some 

 distance from the water while the tail is still long. They are cer- 

 tain to climb the grasess and sedges and to sit on floating leaves 

 and twigs before the metamorphosis is completed. 



In June they may be found in hundreds among the brown 

 leaves and green moss of the bank. They are little, dark-coloured, 

 leaping objects, which from their small size we might mistake for 

 young toads, if we did not examine them closely. They have not 

 yet gone very far from their pond or marsh, but their diligent 

 search for gnats, mosquitoes, and ants has already begun. 



When we stand on the sphagnum border of the marsh and 

 look into the water, we see so many enemies of these tadpoles, 

 that the wisdom of their early escape to land life appeals to us. 

 There are water-beetles and bugs, leeches, diving-spiders, and the 

 larvse of dragon-flies and caddis-flies. There are always newts 

 to devour them. There are Leopard frogs perhaps, and certainly 

 Green frogs, that eat the adult Pickerings as well as the tadpoles. 



Very often the marsh or pool dries up before the development 

 is completed. The water recedes, to leave a small pool measured 

 only in feet, and perhaps only in inches, where enemies and tad- 

 poles are crowded together/ If the evaporation proceeds too 



The mouth structure of the tadpole of the Pickering's Hylo. is like that of the tadpoles oiffyla 

 versicolor (see footnote, p. 121), except that the lower lip has only two rows of teeth, instead of three. 



a It is said by M. H. Hinckley that birds, such as the crow, the heron, and the woodcock, take 

 advantage of such conditions, and make feeding-places of these reduced pools, as is proved by the 

 tracks and borings in the mud adjacent. 



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