WATER BEETLES IN RELATION TO PONDFISH CULTURE. 
257 
Food of Louisiana fish, by H. E. Schradieck. 
[Figures in the last five columns are percentages, the total food being 100.] 
The data for this table of the food of Louisiana fish were taken from manuscript 
notes by H. E. Schradieck on file in the office at the U. S. Fisheries Biological 
Laboratory at Fairport, Iowa. 
None of these fish that ate beetle food were under 40 mm. in length, with 
the exception of the single top minnow and one long-eared sunfish. The former 
is easily accounted for by the fact that it feeds at the surface, and the beetles it 
had eaten were land species that had fallen into the water and were floating on the 
surface. The sunfish were so near 40 mm. in length that it does not constitute a 
real exception. 
The adult hydrophilid beetles furnished the most attractive food, probably 
because they were more numerous in the localities from which the fish were obtained. 
If we include the larvae with the adults, the Hydrophilidae served as food for 16 
out of the 23 fish that ate beetles, or more than 75 per cent. In the next table, 
the data for which were taken also from manuscript notes by H. E. Schradieck on 
file in the office of the U. S. Fisheries Biological Laboratory at Fairport, Iowa, this 
order is reversed and the Dytiscidae have twice the percentage of the Hydrophilidae. 
