VI IIVLIDAE 195 



corner, but occasionally uttering the quaint and rather faint 

 note, they become very lively in the evening, catching insects by 

 long jumps, or investigating the hollows of decaying mossy 

 stumps. Their general colour is then spotless, almost silvery 

 grey. In the day-time they are sometimes suffused with delicate 

 green. 



The propagation has been studied by Miss M. H. Hinckley.^ 

 They pair in shallow pools, in Massachusetts, in May. On the 

 '10th of that month eggs were attached singly, and in groups, 

 on the grasses resting upon the surface of the water ; first drab- 

 coloured, they became lighter in a few hours. Some larvae 

 escaped from the gelatinous envelopes on the following day, the 

 others on the third day ; they clung to the grasses by means 

 of their prominent suckers. The head and body were cream- 

 coloured, with olive dots, and averaged i inch in length. Gills 

 appeared on the fourth day, to disappear again during the four 

 following days, first those of the right, then those of the left, 

 side ; the suckers became less conspicuous, and the general colour 

 turned into deep olive-green, with fine golden dots on the upper 

 and lower surfaces. The eyes were of a brilliant fiame-colour. 

 On the eleventh day the suckers or " holders " had disappeared, 

 and the hind-limbs were indicated by small white buds. By 

 June 5th, i.e. the twenty-seventh day, the toes developed the 

 terminal discs ; the mottling of gold had given way to a uniform 

 olive or pea-green. Movements of the future arms beneath the 

 skin appeared on the 28th of June, at the age of seven weeks. 

 The arms, mostly the right one first, were thrust out on the 2nd 

 of July ; the fins of the tail were absorbed rapidly, and towards 

 the end of the seventh week the nearly transformed creatures 

 began to leave the water. The young frogs changed colour 

 rapidly, in adaptation to their surroundings, but the four 

 specimens which survived were never all found to be of the 

 same colour during the next three months. They first lived 

 upon Aphides, later upon flies, and they were alert nocturnally. 

 About the beginning of October they left the fronds of their 

 fernery and nestled away in the damp earth, which they left 

 only when the temperature rose above 60° F. 



H. vasta of Hayti is the giant of the tree-frogs, reaching a 

 length of 5 inches. In order to support its great weight the 



1 Proc. Bosl. Soc. Xat. Hist. xxi. 1883, p. 104. 



