Part III.] 



Pond Fish Culture. 



149 



THE BULLFROG. 



General Note. 

 Another enemy of small fish is the bullfrog. We raise more 

 or less bullfrogs at the Hatchery. These animals do not always 

 stay where you put them. In the evening they may be seen 

 migrating from one pond to another. However, some of them 

 seem to remain in certain localities, simply making short ex- 

 cursions for food and exercise. They have good strong voices, 

 and well developed vocal cords, and frequently entertain 

 each other by singing solos. However, they spend most of 

 their time sitting around, looking wise and doing nothing. 



Food Habits. 

 Their natural food is made up largely of insects, although 

 they eat many different kinds of live animals, including fish. 

 They are especially fond of the larger water beetles, such as 

 Hydrophilus triangularis and Dytisciis fasciven- 

 tris. These are large water beetles from an inch 

 to an inch and a half in length, frequently found 

 in Kansas ponds and streams. An examination of 

 a number of stomachs taken from frogs that lived 

 in ponds showed that a good portion of their food 

 at certain seasons of the year and under certain 

 conditions was made up of fish. 

 In the spring of 1910 we made 

 some investigations concerning 

 the food habits of the bullfrogs 

 then living on the Hatchery 

 grounds. At that time there 

 were quite a number of these 

 animals in the ponds. One 

 morning we started some of the 

 Hatchery men out to collect 

 large bullfrogs. They took 

 thirty specimens all told, five 

 from each of the six ponds in 

 the old Hatchery. These ani- 

 mals were killed and immedi- 

 ately dissected in order to find 

 out exactly what they had in 

 their stomachs. The following 

 table will show what they had 

 been eating. 



Food of Thirty Specimens Taken from 

 Hatchery Ponds. 

 The specimens below considered were taken for 

 examination from the ponds on the State Hatch- 

 ery Grounds on April 7 and 8, 1910, between 8 :30 

 and 11:45 A.M. For total length of specimens 

 the animals were stretched out on a board and measured from 

 the end of the nose to the end of the toes. 



Predaceous d i v i n 

 beetle. Common 

 Kansas waters. 



Larva or im- 

 mature stage 

 of the preda- 

 ceous diving 

 beetle. It feeds 

 upon various 

 forms of small 

 water ani- 

 mals, including 

 young fish and 

 tadpoles. I u 

 some localities 

 it is known as 

 the "water 

 tis^er." 



