66 The Pickerel-frog, Rana imlustris LeConte. 



12^06" they put up for air, but saw me and put down immediately; 

 at 12^15'°, when I was obliged to leave for an afternoon class, they were 

 resting on the bottom of the pond 1| feet from the stick. The fourth 

 pair (1906) previously mentioned was merely resting upon another 

 bunch already laid. When we captured them 50 or 60 fresh, sticky 

 eggs were found on the top of the old bunch. 



Another description of a pickerel-frog congress April 28, 1911, will 

 supplement that of May 1907. In a 9-foot square some 31 frogs 

 were mating and laying in a shallow spot. The mated pairs were num- 

 erous and the females backed around aimlessly until a stick or stem 

 w^as found. This a female kept a very short period, changing position 

 or backing to another stem, a process she kept performing in rapid 

 changes. As she moved about, other males interfered and endeavored 

 to secure a hold; when other males troubled her, she helped her consort 

 to kick them aw^ay. Usually an unmated male would grasp the male 

 in possession by a leg or other parts and let go as quickly. Occasion- 

 ally the seizure was long sustained, as with the toads. In one instance 

 a male seized the mated male in front of his hind limbs, lumbar fashion; 

 another male grasped him by the head and maintained his hold. When 

 finally a pair actually were about to lay, the female grasped a stick or 

 stem with her hind limbs and became perfectly horizontal and flattened, 

 her hind limbs drawn up with the heels together. The male's hind 

 legs were parallel to those of the female and slightly within them. 

 The male would draw up his hind legs and thrust them back as if 

 helping to push the eggs out. The frogs were very flat and the female's 

 front feet were brought together. The egg-laying occupied about 3 

 minutes in all. There were 10 to 12 fertilizations. The male released 

 his grasp almost immediately after the complement was laid, and put 

 up for air, but the female remained in position about 2 minutes more. 

 I left the area at 10''50™ and returned at 11 o'clock to find another 

 mass had been laid in the 10-minute interval. 



THE EGGS. 



The eggs of R. palustris are almost invariably submerged and 

 attached to sticks (Plate i, Fig. 2c), twigs, or tufts of grass stems. 

 The species seeks the shallows for egg-laying, although not exclusively. 

 Almost every year we find some egg-masses in the middle of ponds 

 where the water is 1 to 3 feet deep. They tend to lay in special areas 

 (Plate XVI, Fig. 1), as Rana sylvatica and Rana pipiens often do. In 

 1907, in an area 3 by 3 feet, 18 bunches were deposited; in another 

 area, 4 by 3 feet, 12 bunches were recorded. In 1911, in another spot, 

 3 by 3 feet, 31 bunches were found. All of these areas gave excellent 

 illustrations of the building of bunches, one upon another. In 1907 at 

 least one case of 4 successive bunches upon one twig was recorded, 10 



