FROGS. 19 



forms. If one wish to stock his inclosure or ponds with adults, let 

 him do it by the first of July, or preferably by June 1. 



The southern bullfrog is one of the common forms of the deep- 

 wooded swamps and of the water-lily-filled watercourses of such 

 areas and is often called the swamp bullfrog. Equally frequent is 

 it in the vast, open, swampy stretches or ''prairies" of the Ever- 

 glade, Okefinokee, and other famous southern swamps. The bright 

 green and yeUow of the under parts make it very conspicuous when 

 in hand. Often these creatures will not dive until within an oar's 

 length, but in the main this species is a shy form. Occasionally the 

 author has taken them when visiting trap lanterns in aquatic situa- 

 tions. 



The southern leopard frog is similar to the common leopard frog 

 in habitat, mating, and general habits. 



MATED PAIRS (PLS. XI AND XIl). 



Some articles on frog culture advocate stocking the suitable wa- 

 ters with a sufficient number of mated paire of niature frogs. To 

 the writer the main consideration in using individual breeders or 

 mated pairs is that it positively proves to the beginner the identity 

 of the species with which he is stocking his waters. Heretofore the 

 most creditable published attempts with eggs or tadpoles taken 

 afield leaves one with the impression that the experinienter was not 

 absolutely sure whether he had good or worthless species. If mated 

 pairs be the starting point, avoid pairs mated in captivity by some 

 one other than yourself, for you do not know their period of cap- 

 tivity. If mated by the person concerned within one or two days 

 after being taken in the field, return them to the out-of-door envi- 

 ronment at once. The only sure source of fertile pairs is the field- 

 mated pairs. The writer finds that in at least nme different species 

 of frogs the pairs captured afield usually remain mated, no matter 

 how long the journey to the laboratory or hatchery or pond, how- 

 ever roughly handled, or however hot the glass jar (not advisable) 

 became from sun exposure. If they broke apart on the trip, they 

 soon resumed mating and seldom released their hold when trans- 

 ferred from aquarium to aquarium or from pond to pond. 



When mated pairs are secured in the field, one can reasonably 

 expect them to lay the following night or the next day unless the 

 temperatm^e of the water drops suddenly. Rarely a pair may wait 

 several days before ovulation. The prospective frog breeder can 

 identify his material by the mode of embrace. All of the four prin- 

 cipal commercial eastern frogs belong to the true-frog (Rana) group, 

 in which the male holds the female behind the forearm with his hands 

 appressed to the breast of the female (PL XI, figs. 1 and 2). This is 

 the so-called pectoral embrace, and any mated pair with pectoral 

 embrace found after April 25 is almost positively one of the four 

 principal marketable eastern species. Before April 25 the wood frog 

 pairs might be taken; but if the characters of this species already 

 described are remembered, no mistake will be made. 



Desirable species.^ — Of the four princi])al marketable eastern 

 species, the mating of the leopard frog is easily the most familiar. 

 This species is not restricted to night courtsiiip, although most of it 

 occurs at this time, and more mated pairs can be secured at night with 



3528()°— 21 18 



