30 The American Toad, Bufo lentiginosus americanus LeConte. 



whether the bottom be free or covered with fresh or dead vegetation. 

 So long as water is at hand, their main desideratum is met. In choice 

 of breeding spot, then, the toad is easily suited and will use a greater 

 variety of localities than any other of our Anura. They begin ovula- 

 tion about April 23, the extremes being April 5 and April 30. The first 

 records are: 



For the day preceding the record the maxima range from 50 to 82 

 degrees, and average 65 degrees; for the day of the record they range 

 from 51 to 82 degrees and average 67 degrees. Every record is flanked 

 on one side by 60 or more degrees, with one exception of 56 degrees. 

 A consideration of the maxima for all (not just first) spawning records 

 from 1906 to 1912 gives an average of 68 degrees for the day previous 

 to the record, and 72 degrees for the day of the record. These temper- 

 atures, 68 to 72 degrees, indicate when the species enters the crest of 

 spawning. 



Water-temperatures taken at the place and time of spawning, yield 

 averages of 63 degrees for water-surfaces and 65 degrees for water- 

 bottoms, these seldom descending below 56 degrees (four exceptions 

 from 46 to 51 degrees). Whenever low temperatures like the above 

 occur, the mated pairs are inactive and probably begin under higher 

 temperatures. None of the water-maxima descended below 63 degrees, 

 and the minima were below 56 degrees but once (47 degrees); the 

 maxima averaged 66 degrees, the minima 56 degrees. The effective and 

 prevailing water-temperatures, then, seem to be from 56 to 66 degrees. 



The crest of ovulation comes about April 30. Thereafter the number 

 of spawning pairs diminishes. By May 15 or 20 laying in myriads 

 is about completed and by May 20 or 25 nearly all the toads' eggs 

 are hatched. In June there are a few stragglers, and our latest June 

 records are June 18, 1902, June 17, 1906, and June 21, 1901. In rare 

 instances, the species lays even in July, but we have only one definite 

 date, i. e., July 25, 1907. Professor S. H. Gage adds another late date 

 (July 22, 1902) for Ithaca. So, spawning in this species occasionally 

 extends far beyond the transformation-time of the first-hatched Bufo 

 tadpoles of the season. 



