14 General Account of the Ithacan Anura. 



In both respects they are almost coincident. Ovulation does not come 

 so immediately after emergence as in the first group. They appear, 

 on the average, from April 1 to 3. They may begin to appear at low 

 air-maxima of 48 to 58 degrees, or on the average at air-maxima of 57 

 to 67 degrees. The water-temperatures of appearance are 45 to 53 

 degrees. The first ovulation may come at air-temperatures 2 to 3 

 degrees above the lowest air-maxima of appearence, or 6 degrees above 

 the lowest water-temperature for the same event. On the average, 

 the air advance is 8 to 11 degrees or the rise in water-temperature is 12 

 to 18 degrees. The minimum intervals between appearance and ovula- 

 tion in the two forms are 7 and 10 days; the averages are 17 and 21 days; 

 the maxima are 34 and 32 days. The toad begins spawning on the 

 average about April 23 ; the earliest record is April 5 ; the latest is July 

 25. The pickerel-frog starts egg-laying usually on April 23 ; the earliest 

 record is April 6; the last record of ovulation is May 18. 



The last three to appear delay for considerable periods before 

 ovulation. 



The tree-toad appears, on the average, April 28. It may appear 

 at low air-maxima of 58 to 61 degrees, or usually at an average of 66 to 

 70 degrees. The beginning of ovulation may start at 61 to 72 degrees 

 (3 degrees higher than at appearance), or at a water-temperature 67 to 

 75 degrees. As a general rule, the air-maxima average 72 to 79 degrees 

 (6 degrees higher than the average temperatures of appearance) for 

 breeding, and the water-temperatures average 67 to 71 degrees. The 

 minimum interval between first appearance and breeding is 24 days; 

 the average is 32 days; the maximum is 43 days. The tree-toad begins 

 spawning, on the average, about June 2; the earliest record is May 10; 

 the last record is June 17. 



The green-frog appears on or about April 7. It may appear at a 

 low air-maxima of 54 to 61 degrees, or at water-temperatures of 46 

 to 58 degrees. As a general rule, 61 to 69 degrees is the average range 

 of air-maxima at this time. Ovulation may begin at air-maxima of 65 

 to 74 degrees (11 or more degrees higher than that of appearance), or 

 at a water-temperature from 67 to 71 degrees (21 degrees higher than 

 that of appearance). On an average, it starts at 74 to 76 degrees 

 (13 or more degrees above the average air-maxima of appearance), 

 or at 68 to 74 degrees of water- temperatures (24 degrees above the 

 water-temperature of appearance). The minimum interval between 

 first appearance and first breeding is 32 days; the average is 45 days; 

 the maximum is 61 days. The green-frog proceeds to spawn about 

 June 7 ; the earliest record is May 23 ; the latest is August 10. 



The bullfrog's average date of appearance is May 20. It may appear 

 at air-maxima of 68 degrees, or at water-temperatures of 57 to 69 

 degrees. Usually, the average air-maxima of appearance are 76 to 

 79 degrees. It may begin ovulation at air-maxima of 71 to 72 degrees 



