The Leopard-frog or Meadow-frog, Rana pipiens (Schreber). 53 



The range of dates is from March 5, 1910, to April 11, 1901 and 1912; 

 only four of the 12 records are in April, the others are in March. 



The air-temperatures in this instance may not be directly influential 

 in bringing the first appearance, yet they approximate the effective 

 temperatures and serve as a convenient index of appearance to workers 

 who might wish to know about its probable emergence from hiberna- 

 tion. The maxima for the day of the record show a range from 41 to 

 60 degrees ; for the day previous, 42 to 68 degrees (the record 35 degrees 

 for March 27 occurring when frogs were taken beneath stones) . The 

 average for the day of the record is 53 degrees; for the day previous, 50 

 degrees. 



Numerous w^ater-bottom and water-surface records taken at the time 

 and in the place of appearance show averages of 43 and 46 degrees, or 

 range from 41 to 50 degrees, a surprisingly close parallel with results 

 secured with maximum air-temperatures. When the air-temperatures 

 begin to approach 41 to 45 degrees, we may expect the appearance in 

 spring; and when it mounts to 50 to 53 degrees, they ought to appear 

 in numbers. When the water reaches 41 to 50 degrees, or an average of 

 43 to 46 degrees, they may be confidently expected. 



THE VOICE. 



In early spring the leopard-frogs form the second swamp-chorus to 

 arrest attention. Individually, not possessing a loud voice, these 

 concourses in our swamps, when most vociferous, can not well pass 

 unnoticed. The croak may be a long low guttural note, 3 or more 

 seconds long, followed by 3 to 6 short notes, each a second or less in 

 length. At other times the short notes 

 may precede, or the long and short be 

 interspersed in innumerable ways, or the 

 song may be composed entirely of either 

 short or long notes. (See "Voice" under 

 wood-frog.) In the early stages of the 

 season, the croak may at times be sub- 

 dued. This form begins croaking from 

 3 to 18 days, or on the average 7 days 

 after first appearance, the range of dates 

 being March 23 to April 12, or the average March 31, 

 1911 the records are shown in table herewith. 



From maximum air-temperatures it appears that the species begins 

 to croak at 50 degrees or lower. Somewhere between this temperature 

 and 60 to 63 degrees, we may expect the chorus to begin or may find it 

 at its height. Water-temperatures taken at croaking reveal records 

 as low as 41 to 48 degrees. Doubtless both air and water influence 

 them, for at such times they may be on the banks or on water's surface 

 w^hich responds more or less to the air-temperatures. About the middle 



In 1906 to 



