224 



Conservation Department 



they ran from 4 to 10 inches. They are to be considered as small 

 adult trout. No distinction is made here as to the individual foods 

 selected by the different kinds of trout. In Table 4 consumed 

 foods are placed on a 100 per cent basis ; vegetation, trash, debris 

 and indigestible materials being omitted entirely though some 

 usually occurs in most stomachs. The columns headed "Terrestrial" 

 give the numbers of terrestrial or land insects of each class found 

 in the drift and in the stomachs and include all insects or other 

 animals which normally do not live in or on the water. ''Aquatic" 

 is used to designate those animals, mostly insects which live in or 

 on the water such as stonefly nymphs, caddis lain^ae, etc. At the 

 bottom of Table 4 the term ''Miscellaneous" includes a few 

 millipedes, centipedes and dragonfly nymphs which were taken in 

 both drift and stomachs but which were of little importance in 

 these studies. It is to be remembered that this data is given in 

 per cent by number and not per cent by volume as has been done 

 in most other works on stomach contents of fishes. In a eomparison 



Table 4. — Comparison of Foods Consumed and Available Foods 



Data derived from examination of 147 trout stomachs taken during 29 drift net 



catches in June, July and August, near Ithaca, N. Y., 1928 



ORDER 



Mayflies 



Caddisflies 



Two-winged flies 



Beetles 



Ants, bees, wasps. . . . 

 Plant lice, aphids, etc 



Stoneflies 



Grasshoppers, etc. . . . 



True bugs 



Moths 



Spiders 



Shrimps, crabs, etc. . . 



Worms 



Fish 



Miscellaneous 



Consumed foods from 

 stomach examinations 



Terr.' 



226 



22 



134 



137 



153 



107 



10 



31 



25 



21 



17 







8 







4 



Aquatic 



356 



528 

 187 



33 

 

 



41 

 

 2 

 

 3 



15 

 

 4 



18 



Per 



cent 



29.70 

 26.37 

 15.39 

 8.15 

 7.33 

 5.13 

 2.44 

 1.49 

 1.29 

 1.01 

 0.96 

 0.72 

 0.38 

 0.19 

 1.25 



Available foods from 

 drift net catches 



Terr. 



675 



43 



627 



111 



130 



451 



29 



6 



50 



4 



23 















36 



Aquatic 



102 



59 



38 



30 











9 







12 











5 















Per 

 cent 



31.46 

 4.13 



28.14 

 5.71 

 5.26 



18.26 

 1.54 

 0.24 

 2.51 

 0.18 

 0.93 

 0.2 

 0.0 

 0.0 

 1.45 



of foods consumed by trout and available foods this seemed the 

 most practical manner of presentation since thousands of organisms 

 were being handled in a limited period of time and it would have 

 been very diflficult to calculate volume of each class of drift and 

 bottom food as collected. 



It is shown in Table 4 that mayflies formed 29.70 per cent of all 

 foods consumed and 31.46 per cent of all available foods. In other 



♦ Terr.— Terreatrial. 



