The Food of Firsh-Wafer Fishes. 437 



October, 1881, and at Chicago in 1885. Numbers of others 

 were examined, but without result, as they had been kept until 

 the food was all digested. 



These five specimens had taken only animal food, one of 

 them only Entomostraca — ninety per cent, of these being the 

 common Daphnia of the lakes (/>. hyalina), and the remainder 

 consisting of a few specimens of Bosmina, Chijdorns sphericus, 

 and Cyclops. The food of the remaining four was altogether 

 insects of terrestrial origin. In one were recognized great 

 quantities of winged ants (Myrmicida3), another had eaten 

 only Lepidoptera, and still another winged tipulids (craneflies). 

 In the food of one, numerous specimens of the common scjuash 

 beetle {Diabrotiea vittata) were recognized, and a large quan- 

 tity of undetermined Homoptera. An example of the homop- 

 terous insect Diedrocephala moJUpes was detected in another. 



Two small specimens of this species, hardly to be classed 

 as young, respectively two and six inches long, had fed, like 

 most of the adults examined, chiefly upon terrestrial insects, 

 the shortest specimen upon small Diptera (ninety per cent.)and 

 the homopterous insect Typhlocyba. The other example was 

 taken from the stomach of a lake catfish {Idalurus lacustris) 

 from Lake Michigan. It had eaten a variety of terrestrial 

 species, including an ant, several minute Homoptera, Coriscns 

 ferns, a species of Amnestus, and examples of the families 

 Staphylinidai and Anthicidae. 



FAMILY DOROSOMATID^. 



DOROSOMA CEPEDIANUM, LeS. GiZZARD SHAD ; HiCKORY ShAD ; 



Mud Shad ; Thread Herring. 



This remarkable fish occurs everywhere in the larger 

 streams and in the ponds connected with them, but not in iso- 

 lated lakes. It is marine in origin, swarming in the coast 

 waters from Delaware to Mexico. 



The mouth is toothless except in youth.* The gills are 

 remarkably disposed within a rather small gill chamber. The 



* For its juvenile characters and an account of the food of the 

 young, see Bulletin 111. St. Lab. Nat. Hist, Yol. I., Xo. 3, pp. 68-70. 



