I 82 ARTHUR M. BANTA. 



male over a female attract males from all directions. Hence 

 sex-recognition on the basis of method of movement can be only 

 very tentative and preliminary. 



The female wood frog when attacked by a male apparently 

 makes every effort to escape both on the approach of the male 

 and when he attempts to gain a hold on her. After the hold is 

 once gained her struggles cease. When the male is approached 

 by another male he sometimes apparently resists as vigorously 

 or perhaps even with greater effect than the female, for she is 

 heavy with eggs. But more often the male makes little or no 

 show of resistance and is apparently as quickly left alone whether 

 he resists or not. Hence there seems no consistent difference 

 in the resistance offered by the two sexes when seized by a male. 



The females at the breeding season, at least before the eggs 

 are laid, are nearly all in the reddish brown color condition while 

 the males are much darker. But exceptions to this color dis- 

 tinction between the sexes have already been noted. It is 

 possible however that the color of the female plays some part in 

 sex-recognition, for when used as decoys the dark females which 

 had deposited the eggs were less frequently paired with than the 

 reddish brown ones and this was possibly true to some extent 

 with a dark female which still retained the eggs. 



Thus it appears that the color of the female may possibly be 

 a factor and that the peculiar behavior of the female is probably 

 a factor in sex-recognition. But there seems unquestionably 

 another factor involved when the male approaches closely or 

 touches his prospective mate. Males were seen time and again 

 to approach eagerly to within a few inches of other males only 

 to turn back without coming into contact with or actually 

 attempting to seize them. To be sure two or three instances of 

 such behavior were noted when a male approached a female but 

 they were most exceptional. When a male approaches nearly to 

 a female his activity increases tremendously, in many cases before 

 he can have actually touched her. On one occasion a male was 

 seen to stop swimming within eight or ten inches of an unpaired 

 female which was resting quietly at the surface. After a short 

 time, perhaps ten or twenty seconds, with a rapid and vigorous 

 movement he suddenly seized the female. The suddenness and 



