Ranidae 



be over before the first of May. (Fig. 250.) After that time 

 their voices are never heard. 



In colour, the eggs are chocolate-brown above and white 

 below. If laid early, they develop very slowly, requiring at 

 least a month to reach the hatching stage. (Fig. 248.) If laid 

 later, when the temperature of the water is much higher, the 

 development is so much more rapid that the tadpoles may hatch 

 in nine or ten days. The development is especially rapid in 

 shallow temporary pools. The young tadpoles are nearly black 

 in colour. The external gills become considerably longer and 

 more branched before their absorption than do those of the 

 Leopard Frog. (See Fig. 210.) 



The tadpoles of the Wood Frog eat* not only the green 

 jelly-mass from which they themselves hatch, but also the soft 

 green spheres within the jelly-masses vacated by young salaman- 

 ders. Like other tadpoles, they act as scavengers by greedily 

 devouring all dead animal matter of the pond. 



In late May, the margins of the ponds will be found swarm- 

 ing with young Wood Frogs with tails of varying lengths. The 

 frogs (minus the tails) are f inch long, about the size of a male 

 adult Pickering's Hyla. Their hind legs are extremely long, 

 and the webs are fully developed. The lateral folds show red- 

 brown on a dark wood-brown background. The young frogs 

 are active and shy. 



In permanent ponds or in deep or well-shaded temporary 

 pools, the development is more slow, because the pool endures 

 longer, and the frog is somewhat larger when it leaves the water. 



In late June, the brown leaves of the bottom of such a pond 

 are covered with Wood Frog tadpoles that just match the leaves 

 in colour. Many of them have the legs well developed, perhaps 

 the arms also. With their plump " pollywog " bodies and their 

 long waving tails, they are much larger than the young frogs 

 that have left the water. 



The variation in colour among the Wood Frogs is great 

 indeed, and the colour changes are fairly rapid. The young 

 frogs are likely to be dark in colour, more often than light; and 

 when light, they are more nearly grey than brown. The older 

 ones vary from a colour so light that it might be called flesh- 



1 The mouth structure of R. sylvalica is like that of R. calesbiana (see footnote, p. 23s), except 

 that the lower lip is broader and bears four rows of teeth, instead of three. 



