General Account of the Ithacan Anura. 



13 



Table showing spawning dates of the different species, the intervals between first appearance and 

 ovulation, dates of first appearance, and temperatures of ovulation. 



Species. 



Spawning dates. 



Intervals between 



first appearance 



and ovulation. 



Average 

 date. 



Range of spawning 

 period. 



Average. 



Range. 



Rana sylvatica 



Hyla pickeringii 



Rana pipiens 



Bufo lentiginosus americanus . 



Rana palustris 



Hyla versicolor 



Rana clamata 



Rana catesbeiana 



Apr. 4 

 Apr. 10 

 Apr. 11 

 Apr. 23 

 Apr. 23 

 June 2 

 June 7 

 June 28 



Mar. 19 

 Mar. 30 

 Mar. 29 

 Apr. 5 

 Apr. 6 

 May 10 

 May 23 

 June 16 



to Apr. 30 

 May 10 

 May 15 

 July 25 

 May 18 

 June 17 

 Aug. 10 

 July 10 



days. 



2 



6 

 17 

 21 

 23 

 32 

 45 

 44 



days. 

 to 13 

 5 15 



7 

 7 

 10 

 24 

 32 

 31 



25 

 34 

 32 

 43 

 61 

 54 



Species. 



First 

 appearance. 



Order. 



Average 

 date. 



Temperatures of ovulation. 



Maximum 

 air-temperatures. 



Lowest. 



Average. 



Maximum 

 water-temperatures . 



Lowest. 



Average. 



Rana sylvatica 



Hyla pickeringii 



Rana pipiens 



Bufo 1. americanus. . . 



Rana palustris 



Hyla versicolor 



Rana clamata 



Rana catesbeiana. . 



3 



1 

 2 

 4 

 5 



7 

 6 



Mar. 31 

 Mar. 26 

 Mar. 28 

 Apr. 1 

 Apr. 3 

 Apr. 28 

 Apr. 17 

 May 20 



41 to 43 C 

 43 51 

 43 44 

 50 



50 

 61 

 65 

 71 



51 

 51 



72 

 74 



72 



53 to 58 

 52 58 

 51 55 

 65 



68 



72 

 74 

 80 



67 

 69 

 79 

 76 



41 to 48 

 43 48 

 43 48 

 66 



51 

 51 

 67 

 65 

 66 



64 

 75 

 68 

 71 



53 to 60 



53 



53 



63 



57 



67 



68 



70 



55 

 65 

 64 

 71 



74 

 71 



the average, from March 26 to 31. They may begin to emerge from 

 hibernation at low air-maxima of 41 degrees and upwards or at a water- 

 temperature of 41 to 46 degrees. Usually, however, first appearances 

 come on the average at air-maxima of 50 to 53 degrees. An advance 

 of to 2 degrees above the lowest air- and water-maxima may bring 

 the beginning of ovulation, but ordinarily a rise of 1 to 3 degrees above 

 the average air-maxima of appearance causes it. The minimum 

 intervals between appearance and ovulation for the three species are 

 0, 5, 7 days; the average intervals, 2, 6, 17 days; the maximum intervals, 

 13, 15, 25 days. The wood-frog starts ovulation, on the average, about 

 April 4, but has begun as early as March 19, or extended it to April 30. 

 The peeper has begun, on the average, about April 10, but the earliest 

 record is March 30, and the last extends well into May. Finally, the 

 meadow-frog usually has begun April 11; the earliest record is March 

 29, and the last record is May 15. 



The second group consists of the toad and the pickerel-frog, re- 

 spectively fourth and fifth in first appearance as are they in ovulation. 



