44 BULLETIN OF THE lUIREAU OF FISHERIES. 



forenoon and toward evening. Thus the contents of these stomachs outfht to rt']irc 

 sent fairl}' well the natural food of the trout at this season of the j'ear. 



About 40 of the stomachs were examined at the time the trout were cauj>lit. 

 while the remainder were preserved and their contents have been examined since 

 the time of the expedition. Most of the specimens whose stomachs were exam- 

 ined at the time of their capture were measured and a record of the length was made 

 along- with the record of contents of the stomach. In some cases also the sex of the 

 individual was noted. It was not found practicable to keep a I'ecord of the lengtli 

 and sex of all the specimens from which stomachs were taken and preserved, l)ut the 

 stomachs of specimens obtained from different localities were kept separate* and a 

 record made of the longest and shortest specimens from which they were taken. 



The relative quantity of food in each stomach was estimated — that is, whether 

 the amount of food found was a quarter, or a half, etc., of the quantity the stomach 

 would hold with ordinary distension. The relative amount of the various food ele- 

 ments was then estimated and recorded in percentages. The percentage method was 

 used rather than the counting method because the contents of many stomachs con- 

 sisted largeh' of fragments so small that it was impossible to place them in the proper 

 group or groups of insects. However, the number of individuals making up the 

 various percentages was also recorded in cases where it could readily be determined. 

 Onlj' a very general classification of the stomach contents was attempted and the fol- 

 lowing record will show how the various items were noted: Specimen No. 7, length 

 7 inches; stomach about two-thirds full; contents — 1.5 per cent remains of 7 stone- 

 fly nymphs, 95 per cent Chironomidaa (761 chironomid larvi^ and 1 pupa), 2 per cent 

 1 large fly, 0.5 per cent elytron of a small beetle, 1 per cent ants. The insect frag- 

 ments that were too small to be identified accurately were recorded under the head 

 of "insect fragments" and the Chironomid^ were noted separately from the other 

 Diptera because, in general, they were found to be a more important food element 

 than the other Diptera. The other groups are self-explanatory. Tlie following is a 

 summarized record of the results: 



Salmo whitei Evermann. 



South Fork of the Kaweah Kivek. — The stomachs of 12 specimens obtained 

 from this stream at South Fork Meadows, on July 15, 1904, were studied. The 

 specimens varied in length from 5.5 to 8 inches. All the stomachs except 1 were 

 estimated to be half full or more. 



Ari>'-/uu'i?i(. — Two per cent of the contents of 1 stomach consisted of spiders. 



_Ejy/ieiiii'ri(7a. — Three stomachs contained Ma^^-fly nymphs, two 5 per cent, and 

 the other 3 pev cent. 



Plecoptera. — Forty per cent of the contents of 1 stomach consisted of adult 

 stone-flies, and 2 others contained 5 and 1.75 per cent stone-fly nymphs. 



Orthoptei'a. — The remains of a gi-asshopper (locust) constituted 25 per cent of 

 the stomach contents of 1 specimen. 



IL'iitlpiera. — One specimen had eaten 1 per cent Hemiptera. 



Ti'ielioptera. — Four stomachs contained 90, 25, 15, and 5 per cent caddis-fly 

 larva\ and 8 containe'd 90, 20, and 1 per cent cases of caddis-fly larva\ 



Diptera. — Three specimens had eaten 10, (i, and 2 per cent Diptera. 



