6 General Account of the Ithacan Aiiura. 



normal range. Four species are mainly influenced in their outcomings 

 by air-temperatures. The lowest air-maxima for these four forms 

 range from 41 to 58 degrees (17 degrees), and the average air-maxima 

 reach from 51 to 66 degrees (15 degrees). Water-temperature is the 

 important factor in the other four species, although air-temperature 

 plays a part; in these four the range of water-temperatures extends 

 from 41 to 57 degrees (16 degrees). Naturally enough, the range of the 

 air-temperatures is greater because of the lesser role air plays. The 

 lowest air-maxima prevailing at the first appearances of these forms 

 may be from 41 to 68 degrees (27 degrees), and the average air-maxima 

 from 50 to 76 degrees (26 degrees) . 



THE MATING.* 



It is commonly believed that the mating of Anura occurs only at 

 night. This seems to be the general rule with the Ithaca representa- 

 tives of the group; nevertheless, mating during the day has been 

 observed in the field with five species {Rana sylvatica, pipiens, cla7nata, 

 and palustris, and Bufo lentiginosus americanus), and in the laboratory 

 with one more {Hyla pickeringii) . 



The mating eagerness of the common toad is well-known. It will 

 grasp anything embraceable that moves or comes in its way. None 

 of our Ranidse or Hylidse has displayed any such fervor in the field. 

 In these, there is no such preponderance of males in any one place, 

 though in both families, when several males are kept in an aquarium 

 with only one or two females, instances have occurred where a female 

 was embraced by two males — a condition occasionally found in the 

 field. Usually such cases are of very short duration, no such tenacity 

 being evident as in Bufo, where sometimes six or seven males continue 

 in a mass about the female for several hours (Plate xiii. Fig. 6). 



The degree of ardor in the males seems to be in proportion to the 

 gregariousness of the species, or, in other words, the greater the com- 

 petition for the females the more intense the clasping instinct of the 

 males. The eight species seem to fall in the following order of mating 

 strength, namely: the toad, the meadow-frog, the pickerel-frog, the 

 wood-frog (the swamp cricket-frog), the peeper, the tree-toad, the green- 

 frog, and the bullfrog. It will be observed that the first forms are our 

 most abundant species, and the last are the least common. Further- 

 more, the first in the list are gregarious and the last two quite solitary. 



It has been reported that males of the two genera, Rana and Hyla, 

 endure mutilation, but not to the extent which has been recorded in 

 the genus Bufo. The males of the Ranidse are, however, sufficiently 

 tenacious in their embrace to admit of killing in this position by the slow 



*For flash-lights of croaking males see Dr. Frank Overton's forthcoming "Frogs and 

 Toads of Ijong Island." Bull. Brooklyn Institute of Arts and Sciences. 



