General Account of the Ithacan Anura. 



13 



Table shoiving spawning dales of the different species, the intervals between first appearance and 

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



Species. 



Rana sylvatica 



Hyla pickeringii 



Rana pipiens 



Bufo lentiginosus americanus 



Rana palustris 



Hyla versicolor 



Rana clamata 



Rana catesbeiana 



Spawning dates. 



Average 

 date. 



Apr. 4 

 Apr. 10 

 Apr. 11 

 Apr. 23 

 Apr. 23 

 June 2 

 June 7 

 June 28 



Range of spawning 

 period. 



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 



Intervals between 

 first appearance 

 and ovulation. 



Average. 



2 

 6 

 17 

 21 

 23 

 32 

 45 

 44 



Range. 



days. 

 to 13 

 5 15 



t 

 7 

 10 

 24 

 32 

 31 



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. . 



Mar. 31 

 Mar. 26 

 Mar. 28 

 Apr. 1 

 Apr. 3 

 Apr. 28 

 Apr. 17 

 May 20 



41° to 43° 

 43 51 



53° to 58° 



43 

 50 

 50 

 61 

 65 

 71 



44 

 51 

 51 



72 

 74 



72 



52 

 51 

 65 

 68 

 72 

 74 

 80 



58 

 55 

 67 

 69 

 79 

 76 



41° to 48° 

 43 48 



53° to 60o 

 53 



43 

 51 

 51 

 67 

 65 

 66 



48 

 66 

 64 

 75 

 68 

 71 



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. 



