254 



BULLETIN OF THE BUREAU OF FISHERIES. 



abundantly shown by the fact that two- thirds of the fishes enumerated in this list 

 have eaten both terrestrial and aquatic beetles. Among the aquatic forms the 

 Hydrophilidse serve as food more often than any of the other families, possibly 

 because they are more numerous. 



Of the fishes included the bluegill is the most omnivorous, eating everything 

 on the menu except the Haliplidse. However, if the terrestrial beetles were sepa- 

 rated into families corresponding with the aquatic forms, the toothed herring would 

 have to stand first, since it seems to eat anything and everything that comes its way. 



Forbes himself offered the following comment upon his list (1888, p. 484) : 

 Larvae of aquatic beetles, notwithstanding the abundance of some of the forms, occurred in only 

 insignificant ratios, but were taken by 56 specimens, belonging to 19 of the species — more frequently 

 by the sunfishes than by any other group. The kinds most commonly captured were larvae of the 

 Gyrinidae and Ilydrophilidae, whereas the adult surface beetles themselves (Gyriuus, Dineutes, etc.) — 

 whose zigzag-darting swarms no one can have failed to notice — were not once encountered in my 

 studies. 



He was at fault, however, in this last statement, since he noted, on page 519 

 (1888), that a common bullhead {Ameiurus nebulosus) had eaten gyrinid adults. 



Food of the shore fishes of certain Wisconsin lakes, by A. S. Pearse. 

 [Figures in the food columns are percentages by volume, the entire food being 100.1 



Kind of fish. 



Number of fish ex- 

 amined. 



Average length of 

 fish, millimeters. 



Gyrinidae, adults. 



Gyrinidae, larvae. 11 



HaUphdai, adults. || 



HalipUdae, larvae. 1 



Dytiscidae, adults. 11 



Dytiscidae, larvae. 11 



Hydrophilidae, 

 adiilts. 



Hydrophilidae, 1 

 larvae. 



Undetermined 

 beetles. 



Abramis crysoleucas, golden shiner 



3 

 5 

 1 



33 

 3 

 4 

 18 

 18 

 4 

 49 

 10 

 2 

 10 

 10 

 3 

 3 



10 

 1 

 1 



18 

 9 

 9 

 10 

 14 



122.6 



77 

 274 



36 



51.8 



20 



31.8 



29.5 



48.5 



35.4 



38 



116 

 54.8 

 45.4 

 69.6 

 30.6 



156 



200 



126 



103 

 42.6 

 51.1 

 49.3 

 20.6 











1 



2 











Ambloplites rupestris, redeye 







2.6 







3.4 







Ameiurus melas, black bullhead 





6 





2 







Ameiurus nebulosus, common bullhead 



0.5 















Catostomus commersonii, common sucker 









2.3 











Cyprinus carpio, German carp 





2.5 







2.5 









Etheostoma lowse, Iowa darter 







0.1 



2.5 





0.3 









1.5 











11.2 











9 





Fundulus diaphanus menona, top minnow 















6.6 



6 



Lepomis incisor, bluegill 

























2.5 

 .3 

 .2 

 .6 











Micropterus salmoides, large-mouthed black bass 



























































5 



















.3 

























28 









3 



















.2 



1.1 



2.3 





















33.2 









.2 

 2.0 













































3.5 



















The relative amounts of beetle food given in this table seem at first sight so 

 small as to be hardly worth considering, but such is by no means the case. The 

 total number of fishes examined by Dr. Pearse (1918) was 1,576. In the general 

 summary of foods eaten by these fishes the largest single item was that of insects, 

 36.30 per cent, nearly twice the size of its nearest rival, the Entomostraca. The 

 insects contributing the most food were the Diptera, those second in order were the 



